1. Tc307 3 018 H 4f27e Automatic Transaxle Diagnostic Cg7860sen 65

Technical Service Training

4F27E Automatic Transaxle Curriculum Training TC3073018H Diagnostics

Student Information

CG 7860/S en 10/2000

Introduction

Preface

After a one year “black box phase”, the 4F27E automatic transaxle offered in the Focus has been released for repair in service. The course on the “4F27E Automatic Transaxle, TC3073016H” was developed to give technicians the skills and the required knowledge for correct diagnostics and successful repairs. The course consists of the following Student Information publications:
Curriculum Training “4F27E Automatic Transaxle – Design and Operation”, CG 7859/S
Curriculum Training “4F27E Automatic Transaxle – Diagnostics”, CG 7860/S

This Student Information publication describes the transaxle control system including all its electronic components, and gives important notes on transaxle diagnostics. This Student Information publication is arranged in lessons and designed as a self-learning medium in line with the new Ford global training concept. Each lesson begins with a list of the objectives to be achieved in the course of the lesson and ends with test questions to check learning process. The answers to these are to be found at the end of the Student Information publication.

Please remember that our training literature has been prepared solely for FORD TRAINING PURPOSES. Repair and adjustment operations MUST always be carried out according to the instructions and specifications in the workshop literature. Please make extensive use of the training courses offered by Ford Technical Training Centers to gain extensive knowledge in both theory and practice.

Service Training

1

Contents

Introduction Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Lesson 1 – Preliminary checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 At a glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Customer concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Know and understand the customer concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Fluid level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Checking the transmission fluid level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Fluid condition check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Checking condition of the transmission fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Sources of faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Checking possible sources of faults affecting transaxle control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Checking adjustment of the selector lever cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Test questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Lesson 2 – Transaxle control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 At a glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Powertrain control module (PCM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 EEC V PCM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Limited operation strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2

Service Training

Introduction

Contents Page

Selector lever positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Selector lever position “P” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Selector lever position “R” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Selector lever position “N” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Selector lever position “D” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Selector lever position “2” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Selector lever position “1” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ESSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Control of shift operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Test questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Lesson 3 – Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 At a glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 TP sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 MAF and IAT sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 CKP sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 TSS sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 OSS sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 TR sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Recognition of selector lever position and actuation of reversing lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Transmission of the starter motor solenoid current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Stoplamp switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 TFT sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 O/D switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Test questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Service Training

3

Contents

Introduction Page

Lesson 4 – Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 At a glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Solenoid valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Solenoid valve actuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Main regulating valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Shift solenoid valves SSA and SSB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 PWM solenoid valves SSC, SSD and SSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Air conditioning relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Selector lever shift lock solenoid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Ignition key lock solenoid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 O/D indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Powertrain warning indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Test questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Lesson 5 – Diagnostic instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 At a glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Transaxle operation check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Shift point road test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Special testing procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Line pressure test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Stall speed test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Air pressure test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Test questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

List of abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Answers to the test questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

4

Service Training

Lesson 1 – Preliminary checks

At a glance

Objectives On completing this lesson, you will be able to:
question the customer about the concern and the operating conditions
check and if necessary correct the transmission fluid level
check and assess the condition of the transmission fluid
check the vehicle for possible external sources of faults affecting transaxle control

Service Training

5

Customer concerns

Lesson 1 – Preliminary checks

Know and understand the customer concern
Before a diagnosis can be made, it is essential to fully understand the customer concern.
Therefore, the customer must be questioned about the operating conditions in which the concern occurs.
If possible, the customer concern should be reproduced in a road test with the customer.

The following operating conditions should be known: Cold

Warm-up phase

Normal operating temperature

Under 0°C

0 – 20°C

Over 20°C

Good

Poor

Off-road

Urban traffic

Interurban travel

Highway

Unladen

Laden

When upshifting

When downshifting

Engine operating state

Exterior temperature

Surface state

Traffic conditions

Vehicle laden state

In overrun

Concern occurs

6

Service Training

Lesson 1 – Preliminary checks

Fluid level check

Checking the transmission fluid level NOTE: The fluid level must be correct for the transaxle to operate correctly.
The following conditions must be satisfied to carry out the fluid level check correctly: – the vehicle must be on level ground, – the engine must be idling, – the selector lever must be moved through all the positions several times,

7748/47/VF

– the selector lever must be positioned in “P”, – the transmission fluid temperature should be 55 ± 5°C.
In these conditons the fluid level must lie in the middle between the “MIN” and “MAX” marks on the fluid level indicator.
The fluid level must be corrected as necessary and the fluid level check repeated.
The difference between the “MIN” and “MAX” marks is 0.4 liters. NOTE: Always fill with the specified transmission fluid. Refer to the current service literature for the specification. NOTE: If transmission fluid is being added, the vehicle should be driven forwards and backwards briefly to allow the transmission fluid to flow out of the filler pipe and avoid distortion of the measurement. NOTE: The transmission fluid is designed to last the life of the transaxle and has not to be changed.

Service Training

7

Fluid condition check

Lesson 1 – Preliminary checks

Checking condition of the transmission fluid
If the customer has indicated a concern, the check on the fluid level should be followed by a check on the condition of the fluid.
The color and smell of the fluid may provide an initial indication of possible transaxle damage. NOTE: The fluid should be a dark red color. A brown or black discoloration indicates transaxle damage.
To identify deposits, the transmission fluid should be dripped onto an absorbent towel and the mark inspected.

7860/01/VF


If solid particles are found, the fluid pan must be removed for further checking.
If the fluid pan is found to contain further deposits which indicate contamination of the fluid and transaxle damage, the transaxle must be disassembled, the components checked and changed as necessary and the transaxle cleaned completely.

8

Service Training

Lesson 1 – Preliminary checks

Sources of faults

Checking possible sources of faults affecting transaxle control
Before carrying out a comprehensive transaxle diagnostic check, various sources of faults should be excluded. These include: – loose or corroded cables and connectors, – retrofitted auxiliary equipment not approved by Ford such as air conditioning, cellular phone, speed control system for example, – non-approved tire sizes. NOTE: Customer concerns relating to the automatic transaxle may also be attributable to malfunctions in the engine management system.

Checking adjustment of the selector lever cable
The adjustment of the selector lever cable is checked with the selector lever in position “D”.
In this position the marks on the shift shaft lever must line up with the marks on the transmission range (TR) sensor. NOTE: An incorrectly adjusted selector lever cable can cause stiff operation of the selector lever and differences between the selected transmission range and the range actually obtained.

Service Training

ELE0008134

9

Test questions

Lesson 1 – Preliminary checks

Find the correct answer or fill in the gaps. 1.

Various conditions must be satisfied to carry out the transmission fluid level check correctly. Which of the following conditions is INCORRECT?

V V V V 2.

c) The selector lever should be moved through all the positions several times and left in position “P”. d) The transmission fluid temperature should be 55 ± 5°C.

a) Brown b) Black c) Dark red d) Yellow

Before a comprehensive transaxle diagnostic check is made, various sources of faults should be excluded. These do NOT include

V V V V

10

b) The engine speed must be kept at 2500 rpm.

Abnormal discoloration of the transmission fluid during the fluid level check may be an initial indication of transmission damage. What is the color of the transmission fluid when in good condition?

V V V V 3.

a) The vehicle must be standing on level ground.

a) loose or corroded connectors. b) retrofitted auxiliary equipment not approved by Ford. c) non-approved tire sizes. d) original accessories.

Service Training

Lesson 2 – Transaxle control

At a glance

Objectives On completing this lesson, you will be able to:
describe the components of the transaxle control system
name the locations of the powertrain control module (PCM) and data link connector (DLC)
describe the basic operation of the transaxle control system
describe the hydraulic limited operation strategy
name the shift operations which can be carried out by the PCM in the different selector lever positions
describe the operation and advantages of controlling shift operations with electronic synchronous shift control (ESSC)

Service Training

11

Overview

Lesson 2 – Transaxle control

2

3

4

14 5 1 6

15

7

8 16

9

17

10

11

13 12

7860/21/VF

12

Service Training

Lesson 2 – Transaxle control

Overview

Key to the illustration opposite 1 EEC V PCM 2 Data link connector (DLC) 3 Throttle position (TP) sensor 4 Mass air flow (MAF) and intake air temeprature (IAT) sensor 5 Crankshaft position (CKP) sensor 6 Turbine shaft speed (TSS) sensor 7 Output shaft speed (OSS) sensor 8 Transmission range (TR) sensor 9 Transmission fluid temperature (TFT) sensor 10 Overdrive (O/D) switch 11 Stoplamp switch 12 Selector lever shift lock solenoid 13 Ignition key lock solenoid 14 Solenoid valves in valve body 15 Air conditioning relay 16 Powertrain warning indicator in the instrument cluster 17 O/D indicator in the instrument cluster

Service Training

13

Powertrain control module (PCM)

Lesson 2 – Transaxle control

EEC V PCM Location
The EEC V PCM is located on the right-hand A-pillar behind the cowl side trim panel.

Operation
On vehicles with an automatic transaxle the 104-pin PCM carries out the transaxle control functions in addition to the engine management.

1


The PCM evaluates the incoming signals from the individual sensors and actuates the solenoid valves in the transaxle valve body directly according to the operating state.

2

Diagnostics
A diagnostic check can be carried out on the transaxle control system through the data link connector (DLC) located close to the central junction box (CJB).

14

7748/20/VF

1 EEC V PCM 2 Inertia fuel shutoff (IFS) switch

Service Training

Lesson 2 – Transaxle control

Powertrain control module (PCM)

Limited operation strategy
If correct gear shift operations can no longer be guaranteed due to failure of certain signals, the PCM switches to a hydraulic limited operation strategy.
In this the PCM no longer actuates the solenoid valves in the valve body.
Continued operation is assured subject to the following limited conditions: – maximum main line pressure (harsh engagement),

7748/43/VF

Powertrain warning indicator

– 3rd gear in selector lever positions “D”, “2” and “1” without the torque converter clutch (TCC), – reverse gear in selector lever position “R”.
The driver is notified of the limited operation strategy by the powertrain warning indicator in the instrument cluster (flashing signal). NOTE: The powertrain warning indicator is also illuminated in the event of the engine overheating or the transmission fluid temperature being too high.

Service Training

15

Selector lever positions

Lesson 2 – Transaxle control

Selector lever position “P”

Selector lever position “2”


No gear is shifted in selector lever position “P”.


Only 2nd gear is shifted in selector lever position “2”. It is not possible to shift into 1st gear.


The parking pawl is engaged manually through the selector lever cable and the shift shaft.

Selector lever position “R”


If the selector lever is moved to position “2” at a higher vehicle speed than that permitted for 2nd gear, the transaxle does not shift down until the appropriate vehicle speed has been reached.


Reverse gear is shifted in selector lever postion “R”.

Selector lever position “1”

Selector lever position “N”


Only 1st gear is shifted in selector lever position “1”.


No gear is shifted in selector lever position “N”.
The powertrain is not immobilized.

Selector lever position “D”
The transaxle control system allows all the gears to be shifted in selector lever position “D” and when the O/D switch is not operated.


In addition to the 1st gear one-way clutch, the reverse gear brake is operated to provide engine braking effect in overrun.
If the selector lever is moved to position “1” at a higher vehicle speed than that permitted for 1st gear, the transaxle does not shift down until the appropriate vehicle speed has been reached.


Operating the O/D switch prevents the transaxle shifting into 4th gear or causes it to shift down into 3rd gear.

16

Service Training

Lesson 2 – Transaxle control

Service Training

Notes

17

ESSC

Lesson 2 – Transaxle control

Control of shift operations
During a shift operation, some shift elements are released while others are supplied with pressure. Ideally, these processes should take place simultaneously (synchronously) to avoid jerky shifting (refer to diagram A opposite).
Whenever possible the time taken by the shift operation should remain within the time frame intended for it.
When the shift operation is controlled conventionally, the pressure build up or reduction at the shift elements is set and fixed for the ideal condition (synchronous gear shifting).
Since conventional control offers no way of influencing the control process when shift element wear is varied when the transaxle has been in service for a long time, the pressure build up or reduction may no longer take place synchronously.

Control of shift operations with ESSC
In the 4F27E automatic transaxle an electronic synchronous shift control (ESSC) system is used.
The ESSC system monitors the shift operations and is able to adapt these to the wear in the shift elements over the service life of the transaxle.
This is possible since the individual shift elements are actuated by the modulating valves directly or through accumulators.
The system monitors firstly the shift time and secondly whether the shift operation is synchronous.
If the PCM detects a deviation from the stored set values for the shift time and synchronization of the shift operation, the pressure build up or reduction is adjusted accordingly.


The result of premature pressure reduction (B) at the element to be switched off is an undesired increase in the turbine shaft speed and the engine speed since the element to be switched on is still unable to transmit the input torque.
The result of delayed pressure reduction (C) at the element to be switched off is an undesired drop in the turbine shaft speed and the engine speed as both shift elements are transmitting the input torque. When this happens, the torque is transmitted to the transaxle housing through internal locking.
In both cases the gear shift operation is jerky.
In addition, wear in the shift elements lengthens the shift operation. Consequently, shifting gears in transaxles which have been in service for a fairly long time takes longer.

18

Service Training

Lesson 2 – Transaxle control

4

ESSC

4

A

1

1

2

2

3

3

B 1

1

2

2

3

3

A

C

7748/36/VF

Shift operation 1 2 3 4

Pressure of component to be switched off Pressure of component to be switched on Turbine shaft speed Synchronization range of shift operation

Service Training

A Synchronous gear shift B Non-synchronous gear shift (premature pressure reduction at elements to be switched off) C Non-synchronous gear shift (delayed pressure reduction at element to be switched off)

19

Test questions

Lesson 2 – Transaxle control

Find the correct answer or fill in the gaps. 1.

The EEC V PCM is located

V V V V 2.

V V

a) in 1st gear and in selector lever position “R” in reverse gear. b) in 2nd gear and in selector lever position “R” in reverse gear. c) in 3rd gear and in selector lever position “R” in reverse gear. d) in 4th gear and in selector lever position “R” in reverse gear.

a) Serious transaxle damage ensues. b) The selector lever can only be moved to position “1” at the highest permissible vehicle speed for 1st gear. c) The PCM does not shift the gears until the highest permissible vehicle speed for the gear in question is reached. d) The engine overrevs.

a) electronic standardized shift control. b) electronic synchronous shift control. c) ice and snow driving program. d) electronically assisted hydraulic shift control.

The advantage of ESSC lies in

V V V V

20

d) behind the cowl side trim panel on the right-hand A-pillar.

ESSC means

V V V V 5.

c) behind the cowl side trim panel on the left-hand A-pillar.

What is the result when the driver moves the selector lever to position “1” at a vehicle speed of 120 km/h (75 mph)?

V V

4.

b) in the engine compartment.

With the hydraulic limited operation strategy continued operation is assured in selector lever positions “D”, “2” and “1”

V V V V 3.

a) underneath the glove department.

a) the monitoring and adjustment of the shift operations. b) the monitoring and adjustment of the engine management. c) the monitoring of the torque converter clutch. d) the adjustment to the driving style of the driver.

Service Training

Lesson 3 – Sensors

At a glance

Objectives On completing this lesson, you will be:
familiar with the use of the signals of the TP sensor and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the MAF and the IAT sensors and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the CKP sensor and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the TSS sensor and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the OSS sensor and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the TR sensor and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the stoplamp switch and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the TFT sensor and able to work out possible causes of the fault from the substitute function
familiar with the use of the signals of the O/D switch and able to work out possible causes of the fault from the substitute function

Service Training

21

TP sensor

Lesson 3 – Sensors

Location
The throttle position (TP) sensor is located on the throttle body.

7748/22/VF

Signal use
The TP sensor supplies the PCM with information about the position of the throttle plate.
It also detects the speed of actuation of the throttle plate.
The PCM uses the signals for the following functions among other things:

7748/40/VF

– to determine the shift timing, – to control the main line pressure, – to control the TCC, – for kickdown.

22

Service Training

Lesson 3 – Sensors

TP sensor

Diagnostics/substitute function
In the event of failure of the TP sensor, the engine management system uses the signals of the MAF and IAT sensors as a substitute signal.

A 89

90

91


At the same time the main line pressure is increased so shift operations may be harsh. B

7860/02/VF

A PCM B TP sensor 89 Signal line 90 Reference voltage 91 Reference ground

Service Training

23

MAF and IAT sensors

Lesson 3 – Sensors

Location
The mass air flow (MAF) sensor is located between the air cleaner housing and the air intake pipe leading to the throttle body.
The intake air temperature (IAT) sensor is incorporated in the housing of the MAF sensor.

Signal use
The PCM uses the signals from the MAF sensor in conjunction with the IAT sensor as the primary load signal.

7748/21/VF


The PCM uses the signals among other things for the following functions: 1

2

– to control the shift operations, – to control the main line pressure.

7748/39/VF

1 IAT sensor 2 MAF sensor

24

Service Training

Lesson 3 – Sensors

MAF and IAT sensors

Diagnostics/substitute function

30


In the event of failure of the MAF sensor, the signal of the TP sensor is used as a substitute.

0

1

2

3

B

30


In addition, the main line pressure is increased and shifting to 4th gear is prevented.

A

C

D

E

39

91

36

88

F 7860/03/VF

A B C D E F

Fuse Ignition switch Diode Current holding relay MAF and IAT sensors PCM

36 MAF sensor 39 Signal line – IAT sensor 88 MAF sensor 91 Reference ground

Service Training

25

CKP sensor

Lesson 3 – Sensors

Location
The crankshaft position (CKP) sensor is located on the engine/transaxle flange.

Signal use
The CKP sensor is an inductive sensor which provides the PCM with information about the engine speed and the position of the crankshaft.
The signal is used among other things for the following functions: 7748/23/VF

– to control the TCC, – to check the torque converter slip, – to control the main line pressure. Diagnostics/substitute function
No substitute signal is available for the CKP sensor. If the sensor fails, the engine stops.

A 21

22

B

7860/04/VF

A PCM B CKP sensor 21 CKP sensor (+) 22 CKP sensor (–)

26

Service Training

Lesson 3 – Sensors

TSS sensor

Location
The turbine shaft speed (TSS) sensor is located in the transaxle housing above the transaxle input shaft.

Signal use
The TSS sensor is an inductive sensor which measures the speed of the transaxle input shaft.
The signal is used for the following functions: – to control the shift operations, – to control the TCC, – to check the torque converter slip, – diagnostics (plausibility check). 7748/24/VF

Diagnostics/substitute function
In the event of failure of the TSS sensor, the signal of the output shaft speed (OSS) sensor is used as a substitute signal.
4th gear is deselected.

A


The 3rd–2nd gear shift is no longer carried out.
The TCC is released or no longer actuated. 34

76

B

7860/05/VF

A TSS sensor B PCM 34 Signal line – TSS sensor 76 Reference ground

Service Training

27

OSS sensor

Lesson 3 – Sensors

Location
The output shaft speed (OSS) sensor is located in the transaxle housing above the rotor in the differential.

Signal use
The OSS sensor is an inductive sensor which measures the vehicle speed by means of a rotor located on the differential.
The signal is used among other things for the following functions: – to determine the gear shift timings, – as an input signal for the vehicle speed for the PCM, – diagnostics (plausibility check).

7748/25/VF

Diagnostics/substitute function
In the event of failure of the OSS sensor, the signal of the TSS sensor is used as a substitute signal.
This can result in harsh gear shift operations.

A

58

33

B

7860/06/VF

A OSS sensor B PCM 33 OSS sensor (–) 58 OSS sensor (+)

28

Service Training

Lesson 3 – Sensors

TR sensor

Location
The transmission range (TR) sensor is located on the shift shaft on the transaxle housing.

Signal use
When the shift shaft is moved by means of the selector lever cable, sliding contacts for the different positions inside the TR sensor are tapped.
Separate contacts are present for transmission of the starter motor current when starting in selector lever positions “P” and “N”. NOTE: The selector lever cable must be adjusted correctly to guarantee correct operation of the TR sensor.
The signals of the TR sensor are used for the following functions:

7748/26/VF

– to recognize the selector lever position, – to actuate the reversing lamps in selector lever position “R”, – to transmit the starter motor current in selector lever positions “P” and “N”.

Service Training

29

TR sensor

Lesson 3 – Sensors

Recognition of the selector lever position and actuation of the reversing lamps Diagnostics/substitute function

30

D

C

1

2

R

D

N

P

P

R

N

B

E 7

8

11

4

64

A 7860/07/VF

A B C D E

PCM TR sensor Current holding relay Fuse To reversing lamps


If a fault occurs while the vehicle is moving, the PCM initially calculates whether the vehicle is currently moving forwards or in reverse. The main line pressure is increased with the result that gear changes may be harsh.

30

4 “R” signal 7 “1” signal 8 “2” signal 11 “D” signal 64 “P” and “N” signal
When moving forwards, selector lever position “D” is assumed and 1st gear is no longer shifted.
In the event of a complete failure while the vehicle is moving, the hydraulic limited operation strategy is selected.

Service Training

Lesson 3 – Sensors

TR sensor

Transmission of the starter motor solenoid current Diagnostics/substitute function

30

G

3

3 2 1 0

2 1 0

F

E

D

1

2

D

R

N

P

P

R

N

B 27

C

A M

7860/08/VF

A B C D E F G

Starter motor TR sensor PCM Starter motor relay Bridge Ignition switch Fuse


No substitute signal is available for the TR sensor.
If the connection is broken, the engine cannot be started.

Service Training

27 Passive ant-theft system (PATS)


If there is a short circuit, the engine can also be started in “R”, “D”, “2” or “1”.

31

Stoplamp switch

Lesson 3 – Sensors

Location
The stoplamp switch is mounted on the brake pedal bracket.

Signal use
When the brake pedal is depressed, the stoplamp switch actuates the following components: – stoplamps, – PCM, – selector lever shift lock solenoid.
The signal from the stoplamp switch is used by the PCM to release the TCC when the brake pedal is depressed.

7748/27/VF

32

Service Training

Lesson 3 – Sensors

Stoplamp switch

Diagnostics/substitute function 30


There is no substitute function available for the stoplamp switch.

A


If the connection to the stoplamp switch is broken, the selector lever cannot be moved out of position “P”.

B

NOTE: The lever can be released manually (refer to “Lesson 3 – Actuators: Selector lever shift lock solenoid” in this Student Information publication).

C

D

92

E

7860/20/VF

A B C D E

Fuse Stoplamp switch To stoplamps To selector lever shift lock solenoid PCM

92 Braking signal

Service Training

33

TFT sensor

Lesson 3 – Sensors

Location
The transmission fluid temperature (TFT) sensor is located in the internal wiring harness to the solenoid valves in the fluid pan.

Signal use
The TFT sensor is an negative temperature coefficent (NTC) resistor which measures the transmission fluid temperature.

7748/30/VF


The PCM uses the transmission fluid temperature for the following functions: – the TCC cannot be closed until the transmision fluid reaches the specified temperature, – in extreme sub-zero temperatures it is not possible to shift to 4th gear until the normal operating temperature has been reached, – if the transmission fluid temperature is too high, a preset fixed shift curve is selected and the TCC is closed in 2nd, 3rd and 4th gears; if the transmission fluid temperature continues rising, the powertrain warning indicator is illuminated.

34

Service Training

Lesson 3 – Sensors

TFT sensor

Diagnostics/substitute function
In the event of a short circuit to ground or to battery positive, the following substitute strategy is adopted:

A 91

37

– First, the value measured previously is assumed to be valid. – After a defined length of time the cylinder head temperature (CHT) sensor is used to provide a substitute signal. – If the CHT signal lies above a defined level, the value of the transmission fluid temperature is assumed to be “high” to protect the transaxle.
The PCM cannot detect a malfunction within the tolerance range of the TFT sensor.

B

7860/09/VF

A PCM B TFT sensor 37 Signal line 91 Reference ground


This can lead to undesired changes in shift timing, inconsistent closing and opening of the TCC and to harsh gear changes.

Service Training

35

O/D switch

Lesson 3 – Sensors

Location
The overdrive (O/D) switch is located on the side of the selector lever.

Signal use
The O/D switch sends the PCM a signal to select or deselect 4th gear in selector lever position “D”.
The signal of the O/D switch is used for the following functions: – as an input signal to the PCM to indicate the driver’s wishes, – to display the driver’s wishes with the O/D indicator in the instrument cluster. 7748/29/VF

Diagnostics/substitute function

30


No substitute signal is available for the O/D switch. In the event of failure, it is still possible to shift to 4th gear in selector lever position “D”.

A

B

C 29

D 7860/10/VF

A B C D

Fuse Current holding relay O/D switch PCM

29 Signal line

36

Service Training

Lesson 3 – Sensors

Test questions

Find the correct answer or fill in the gaps. 1.

For what is the TP signal NOT used by the PCM?

V V V V 2.

d) To check torque converter slip.

a) TSS sensor b) OSS sensor c) TFT sensor d) CKP sensor

a) the TSS signal is used as a substitute signal. b) there is no substitute signal available; the engine stops. c) the VSS signal is used as a substitute signal. d) the CKP signal is used as a substitute signal.

The signal of the TR sensor is used for various functions. Which of the following is NOT one of these?

V V V V 5.

c) To control the TCC.

In the event of failure of the OSS sensor

V V V V 4.

b) To control the main line pressure.

Which of the following sensors has NO influence on the TCC control?

V V V V 3.

a) To determine the shift timings.

a) To recognize the manual selector lever position. b) To actuate the reversing lamps. c) To operate the selector lever shift lock solenoid. d) To transmit the starter motor current.

Which of the following possible faults in the TFT sensor cannot be detected by the PCM?

V V V V

a) A malfunction within the measuring tolerance. b) A malfunction outside the measuring tolerance. c) A short circuit to ground. d) A short circuit to battery positive.

Service Training

37

Notes

38

Lesson 3 – Sensors

Service Training

Lesson 4 – Actuators

At a glance

Objectives On completing this lesson you will be able to:
describe the operation of the solenoid valves and work out possible causes of the fault from the substitute functions
describe the operation of the air conditioning relay
describe the operation of the selector lever shift lock solenoid and unlock the selector lever manually in the event of a malfunction
describe the operation of the ignition key lock solenoid
describe the operation of the O/D indicator
describe the operation of the powertrain warning indicator

Service Training

39

Solenoid valves

Lesson 4 – Actuators

1 2 3

6

5

4 7860/19/VF

1 SSB 2 SSA 3 Main regulating valve

4 SSC 5 SSE 6 SSD

Location
Six electronically operated solenoid valves are located on the valve body in the fluid pan: – a main regulating valve, – three PWM solenoid valves (SSC, SSD and SSE), – two shift solenoid valaves (SSA and SSB).

40

Service Training

Lesson 4 – Actuators

Solenoid valves

Solenoid valve actuation Selector lever position

Gear

SSA

SSB

SSC

SSD

SSE

P

N

On

Off

0%

0%

0%

R

R

Off

Off

0%

0%

0%

N

N

On

Off

0%

0%

0%

D

D1

Off

Off

0%

100%

100%

D2

Off

Off

0%

0%

100%

D3

Off

Off

0%

0%

0%

D3 TCC

Off

On

100%

0%

0%

D4

On

Off

100%

0%

0%

D4 TCC

On

On

100%

0%

0%

M2

Off

Off

0%

0%

100%

D3*

Off

Off

0%

0%

0%

D4*

On

Off

100%

0%

0%

M1

On

On

0%

0%

100%

D2*

Off

Off

0%

0%

100%

D3*

Off

Off

0%

0%

0%

D4*

On

Off

100%

0%

0%

2

1

N R D1 D2 D3 D3 TTC

Neutral Reverse gear 1st gear (automatic) 2st gear (automatic) 3rd gear (automatic) 3rd gear (automatic) with torque converter clutch D4 4th gear (automatic) D4 TTC 4th gear (automatic) with torque converter clutch M2 2nd gear (manual) M1 1st gear (manual)

Service Training

NOTE:

For selector lever positions “2” and “1” the table also shows the actuation of the solenoid valves in the event of downshifting from selector lever position “D” at high vehicle speed. (*)

41

Solenoid valves

Lesson 4 – Actuators

Diagnostics/substitute function

A 81

44

1

73

102

99

82

B

7860/18/VF

A PCM B Solenoid valves in valve body


The PCM continuously checks the electrical connections to the solenoid valves. Depending on which fault is detected, dfferent limited operation strategies are employed and a fault code is set.

1 44 73 81 82 99 102

SSB Main regulating valve SSA Main regulating valve SSC SSD SSE

CAUTION: Faults in the electrical connections to the solenoid valves can lead to serious transaxle damage.


Faults in the electrical connections to the solenoid valves can affect gear shifting adversely.

42

Service Training

Lesson 4 – Actuators

Solenoid valves

Main regulating valve Operation
The main regulating valve controls the main line pressure for the different operating conditions in the individual transmission ranges.
The main line pressure is controlled according to the current engine load.
The PCM supplies the main regulating valve with a current of between approximately 0 and 1 amp according to the required main line pressure. Here, 0 amps means maximum main line pressure.

Diagnostics/substitute function
When the PCM detects that the main regulating valve remains switched on all the time, fault code P0747 is set.
A main regulating valve which is switched on all the time leads to slipping clutches at the time at which the fault appears.
When this is detected, the main regulating valve is switched off.
When the PCM detects that the main regulating valve remains switched off all the time or is temporarily disconnected, fault code P0746 or P1760 is set.
A main regulating valve which is switched off all the time leads to harsh gear changes.

Service Training

43

Solenoid valves

Lesson 4 – Actuators

Shift solenoid valves SSA and SSB Operation
The shift solenoid valves SSA and SSB are on/off solenoid valves.
When the shift solenoid valves are energized by the PCM, hydraulic pressure is passed to the corresponding hydraulic valves.
When de-energized, the return from the hydraulic valves is opened.
SSA switches the hydraulic valve – clutch control and the hydraulic valve – 3–4 shift.
SSB switches the hydraulic valve – M1 and R and the hydraulic valve – TCC control.

Diagnostics/substitute function NOTE: In the following tables the upper line indicates the gear shifted in normal conditions. The lower line indicates the gear actually shifted in the corresponding fault condition.
When the PCM detects that SSA remains switched on all the time, fault code P0751 is set.


When the PCM detects that SSA remains switched off all the time, fault code P0750 or fault code P0751 is set.
The following gears are shifted: R N

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 1

2

3

3 TCC

3

3

2

2


When the PCM detects that SSB remains switched on all the time, fault code P0756 is set.
The following gears are shifted: R R

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 1

1

3

3 TCC

3

3 TCC

1

1


When the PCM detects that SSB remains switched off all the time, fault code P0755 or fault code P0756 is set.
The following gears are shifted: R R

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 1

2

3

3

4

4

2

1


The following gears are shifted: R N

44

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 1

3

3

3

3

3

3

1

Service Training

Lesson 4 – Actuators

Solenoid valves

PWM solenoid valves SSC, SSD and SSE
When the PCM detects that SSD remains switched on all the time, fault code P0766 is set.

Operation
The PWM solenoid valves SSC, SSD and SSE control the pressure to the brakes and clutches.


The following gears are shifted:


The PWM solenoid valves are actuated by the PCM with a fixed frequency of 50 Hz.

R R


The pressure is varied by modulating the time for which the valve is switched on within a period (pulse duty cycle) between 0% and 100%.
A pulse duty cycle of 0% means that the pressure channel to the clutches and brakes is opened; a pulse duty cycle of 100% means that the pressure channel is closed and the return is opened.


The following gears are shifted:

3

3

3 TCC

3

3

3

1*


When the PCM detects that SSD remains switched off all the time, fault code P0765 or fault code P0766 is set.
The following gears are shifted:

R


When the PCM detects that SSC remains switched on all the time, fault code P0761 is set.

2

* without engine braking effect

R Diagnostics/substitute function

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 2

2

3

3 TCC

3

3

2

1


When the PCM detects that SSE remains switched on all the time, fault code P0771 is set.
The following gears are shifted:

R R

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 4

4

4

4

4

4 TCC

4

N

R R


When the PCM detects that SSC remains switched off all the time, fault code P0760 or fault code P0761 is set.
The following gears are shifted:

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 1

2

2

2

2

2

2

1


When the PCM detects that SSE remains switched off all the time, fault code P0770 or fault code P0771 is set.
The following gears are shifted:

R R

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 1

2

3

3

3

3

2

1

R R

Service Training

D1 D2 D3 D3 TCC D4 D4 TCC M2 M1 3

3

3

3 TCC

4

4 TCC

3

4

45

Air conditioning relay

Lesson 4 – Actuators

Location
The air conditioning relay is located in the battery junction box (BJB) in the engine compartment.

Operation
The PCM applies ground to the control side of the air conditioning relay depending on the air conditioning control setting.
This actuates the relay (R11) and the air conditioning compressor clutch is engaged.

1

2

7748/46/VF

1 Battery junction box (BJB) 2 Central junction box (CJB)


When the PCM registers a kickdown signal (WOT, 95% open throttle), the ground in the control circuit of the air conditioning relay is switched off for a maximum of 15 seconds.

7748/35/VF

Battery junction box (BJB)

46

Service Training

Lesson 4 – Actuators

Air conditioning relay

Diagnostics/substitute function

15

A 30

B

C

F

E

69

D

7860/17/VF

A B C D E F

Fuse Current holding relay Air conditioning relay PCM Air conditioning compressor clutch diode Air conditioning compressor clutch

69 Air conditioning relay (switch off signal)


No substitute function is available for the air conditioning relay.
If a fault occurs, the air conditioning system will not operate.

Service Training

47

Selector lever shift lock solenoid

Lesson 4 – Actuators

Location
The selector lever shift lock solenoid is located in the selector lever bracket. 1

Operation
When the ignition is switched on, the selector lever shift lock solenoid is operated by depressing the brake pedal (signal from the stoplamp switch). This retracts the locking pin and allows the selector lever to be moved out of position “P”.

2 3

7860/22/VF

1 Solenoid 2 Locking pin 3 Manual release Diagnostics/substitute function 30


If the signal from the stoplamp switch is missing or the ground connection is interrupted, the selector lever can no longer be moved out of position “P”.

A

B C

P R N D 2 1

D

7860/23/VF

A B C D

48

Fuse Stoplamp switch To ignition switch lock solenoid Selector lever shift lock solenoid

Service Training

Lesson 4 – Actuators

Selector lever shift lock solenoid


The selector lever can be moved out of position “P” by operating the manual release.
For this, remove the cover of the release and press a suitable object (for example an ignition key) into the opening until the selector lever can be moved out of position “P”. NOTE: The selector lever will be locked again if moved to position “P” again.

7748/48/VF

Service Training

49

Ignition key lock solenoid

Lesson 4 – Actuators

Location 2


The ignition key lock solenoid is incorporated in the ignition lock. 1

Operation
In selector lever position “P” the ground connection to the solenoid is open. The locking pin does not engage in the ignition lock. The ignition key can be removed.
In all the other selector lever positions the ground connection to the solenoid is closed. The locking pin engages in the ignition lock. The ignition key cannot be removed.

3

7748/28/VF

Illustration of principle 1 Ignition lock 2 Solenoid 3 Locking pin

Diagnostics/substitute function 30


A short circuit to ground means that the ignition key can no longer be removed from the ignition lock.

A


If an electrical connection to the solenoid is cut, the ignition key can be removed in all the selector lever positions.

B

D

P R N D 2 1

C

7860/24/VF

A B C D

50

Fuse Ignition key lock solenoid Selector lever shift lock solenoid To stoplamp switch

Service Training

Lesson 4 – Actuators

O/D indicator

Location
The O/D indicator is located in the instrument cluster and colored green.

Operation
The O/D indicator is illuminated by the PCM through the standard corporate protocoll (SCP) databus after receiving the signal from the O/D switch on the selector lever.

7748/42/VF


It tells the driver that 4th gear is deselected by the transaxle control system. Diagnostics/substitute function
No substitute function is available for the O/D indicator.

A 15

16


If the O/D indicator should fail, the driver will no longer be informed that 4th gear has been deselected.

B C D

7860/25/VF

A B C D

PCM Instrument cluster Instrument cluster microprocessor O/D indicator

15 SCP data line 16 SCP data line

Service Training

51

Powertrain warning indicator

Lesson 4 – Actuators

Location
The powertrain warning indicator is located in the instrument cluster and is colored orange.

Operation
It flashes to tell the driver that the transaxle control system is in the limited operation strategy or that the transmission fluid temperature is too high.

7748/43/VF

NOTE: The powertrain warning indicator is also illuminated in the event of the engine overheating. Diagnostics/substitute function
No substitute function is available for the powertrain warning indicator.

A 15

16


If it should fail, any faults in the transaxle control system or engine overheating are no longer indicated to the driver.

B C D

7860/26/VF

A B C D

PCM Instrument cluster Instrument cluster microprocessor Powertrain warning indicator

15 SCP data line 16 SCP data line

52

Service Training

Lesson 4 – Actuators

Test questions

Find the correct answer or fill in the gaps. 1.

In selector lever position “D” the solenoid valves are actuated in D3 without the TCC as follows:

V V V V 2.

d) SSA off; SSB off; SSC 100%; SSD 100%; SSE 100%.

a) serious transaxle damage. b) slipping clutches. c) harsh gear changes. d) no perceptible differences.

a) the selector lever can no longer be moved out of position “P”. b) the selector lever can always be moved out of position “P”. c) the transaxle control system switches to the hydraulic limited operation strategy.

What could make it impossible to remove the ignition key from the ignition lock?

V V V 5.

c) SSA on; SSB on; SSC 0%; SSD 0%; SSE 0%.

A break in the circuit of the selector lever shift lock solenoid means that

V V V 4.

b) SSA off; SSB off; SSC 0%; SSD 0%; SSE 0%.

A main regulating valve which is switched off all the time leads to

V V V V 3.

a) SSA on; SSB on; SSC 100%; SSD 100%; SSE 100%.

a) A break in the circuit of the ignition key lock solenoid. b) A short circuit to ground in the circuit of the ignition key lock solenoid. c) A short circuit to battery positive in the circuit of the ignition key lock solenoid.

What function does the powertrain warning indicator perform which is NOT directly related to control of the automatic transaxle?

V V V V

a) Indication of excessive engine speed. b) Indication of engine overheating. c) Indication of an anti-lock brake (ABS) module malfunction. d) Indication of an instrument cluster malfunction.

Service Training

53

At a glance

Lesson 5 – Diagnostic instructions

Objectives On completing this lesson, you will be able to:
carry out a road test to check the shift timings as described in the service literature and work out possible causes of the fault from the test results
carry out the line pressure test as described in the service literature and work out possible causes of the fault from the test results
carry out the stall speed test as described in the service literature and work out possible causes of the fault from the test results
carry out the air pressure test as described in the service literature and work out possible causes of the fault from the test results

54

Service Training

Lesson 5 – Diagnostic instructions

Transaxle operation check

Shift point road test NOTE: Refer to the current service literature for the precise procedure and specifications.
To check that the transaxle control system is operating correctly, a road test must be carried out to check the shift timings.

NOTE: Fault or diagnostic trouble codes indicating faults in the vehicle wiring harness, the PCM or sensors not related to the transaxle must be rectified first.


In addition to the shift timings, the operation of the O/D switch and the TCC should also be checked during the road test. NOTE: Engine and transmission must be at normal operating temperature for the test. NOTE: It is recommended that the worldwide diagnostic system (WDS) be connected and that the appropriate signals be selected in the datalogger to establish the shift timings and ensure correct operation of the throttle.

WARNING: The road test with WDS must be carried out with two persons on safety grounds. The passenger can monitor the signals and note the appropriate actual values. Failure to follow this instruction may result in personal injury.
Incorrect shift timings indicate faults in the transaxle control system.
After the road test – and before disconnecting connectors – the fault or diagnostic trouble codes must be read out (KOEO, KOER).
When fault or diagnostic trouble codes are present, carry out the appropriate measures to rectify the fault with reference to the service literature.

Service Training

55

Special testing procedures

Lesson 5 – Diagnostic instructions

Line pressure test NOTE: Refer to the current service literature for the precise procedure and specifications.
The object of the line pressure test is to make sure that the line pressure lies within the tolerance.
If it lies outside the tolerance, this may indicate hydraulic and mechanical malfunctions of the corresponding components.
Connect a pressure test gauge or the WDS to the line pressure test connector.

1

TIA0005613

1 Line pressure test connector


At idle speed note the line pressure in the individual selector lever positions and compare it with the specification.
If the line pressure lies outside the tolerance, this can be due to the following causes:

Test result

Possible cause

Line pressure too low in all selector lever positions

Fluid pump worn Fluid leak at fluid pump or valve body Malfunction of main regulating valve Main line pressure regulating valve sticking

Line pressure too low only in “D”, “2” and “1”

Fluid leak in circuit of 1st–3rd gear clutch

Line pressure too low only in “2”

Fluid leak in circuit of 2nd/4th gear brake band servo

Line pressure too low only in “1” and “R”

Fluid leak in circuit of reverse gear brake

Line pressure too low only in “R”

Fluid leak in circuit of reverse gear clutch

Line pressure too high in all selector lever positions

Malfunction of main regulating valve Main line pressure regulating valve sticking Transaxle control system in hydraulic limited operation strategy

56

Service Training

Lesson 5 – Diagnostic instructions

Special testing procedures

Stall speed test NOTE: Refer to the current service literature for the precise procedure and specifications.

WARNING: Before the stall speed test, check the parking brake is working correctly and apply it securely. Failure to follow this instruction may result in personal injury. CAUTION: The stall speed test must only be carried out after completing the line pressure test with line pressure values within the specification as otherwise further transaxle damage may ensue. CAUTION: Only maintain full throttle in each selector lever position for a maximum of 3 seconds.


If the stall speed is too low, first check the engine idle speed. If this is not correct, rectify the cause of this first.
If the engine idle speed is correct, remove the torque converter and check the one-way clutch of the stator for slipping.
An excessive stall speed may be due to the following causes: Test result

Possible cause

Speed too high in “D”, “2” and “1”

1st–3rd gear clutch slipping

Speed too high only in “2”

2nd/4th gear brake band slipping

Speed too high in “1” and “R”

Reverse gear brake slipping

Speed too high only in “R”

Reverse gear clutch slipping

CAUTION: Release the accelerator pedal at once and shift in Neutral if the maximum permissible engine speed is exceeded. CAUTION: Between the tests in the individual selector lever positions, let the engine run at idle speed for at least 15 seconds to allow the torque converter to cool. NOTE: On completion of the stall speed test the fault or diagnostic trouble codes P0712 and P1783 (excessive transmission fluid temperature) may be set. These must be deleted with the WDS.

Service Training

57

Special testing procedures

Lesson 5 – Diagnostic instructions

Air pressure test

2 1

3

4

10 5 7 8 6 9 7860/27/VF

Plate for transaxle air pressure test 1 Release 2nd/4th gear brake band servo 2 Apply 2nd/4th gear brake band servo 3 Apply 3rd/4th gear clutch 4 Apply reverse gear clutch 5 Torque converter bypass

6 Apply reverse gear brake 7 Torque converter filling 8 Apply 1st–3rd gear clutch 9 Actuate 1–2 accumulator 10 Actuate N–D accumulator

NOTE: Refer to the current service literature for the precise procedure and specifications.


Supply compressed air to the test connection of the clutch to be checked.


Even when the line pressure is correct, intermittent shift faults can occur.
These may be due to a malfunction in the clutches, brakes or brake band.
To locate the component concerned, the air pressure test can be carried out with the appropriate special tool.

NOTE: Only use a compressed air source supplying controlled dry compressed air at 2.75 bar (40 psi).
A dull noise or a movement is perceptible when a component is applied or released correctly.
Whistling noises indicate a leaking seal or valve ball.


To apply the special tool, first detach the fluid pan and drain off the fluid.
Then detach the solenoid valve housing and install the plate for the transaxle air pressure test with the gasket as described in the current service literature.

58

Service Training

Lesson 5 – Diagnostic instructions

Test questions

Find the correct answer or fill in the gaps. 1.

It is a prerequisite for a shift point road test that

V V V V 2.

c) all the fault or diagnostic trouble codes have been deleted. d) the transmission fluid has been changed.

a) a fluid leak at the reverse gear brake. b) a fluid leak at the reverse gear clutch. c) a worn fluid pump. d) a malfunction of the main regulating valve.

Which test must be completed successfully before the stall speed test can be carried out?

V V V V 4.

b) a comprehensive engine diagnostic check has been carried out.

Insufficient line pressure only in selector lever position “R” indicates

V V V V 3.

a) the engine and transaxle have reached normal operating temperature.

a) Shift point road test. b) Line pressure test. c) Air pressure test. d) Read out the diagnostic trouble codes.

What are possible causes of whistling noises during the air pressure test?

V V V V

a) Sticking clutch or brake. b) Blocked fluid channel. c) Leaking gasket or valve ball. d) Sticking accumulator.

Service Training

59

List of abbreviations The abbreviations conform to standard SAE J1930 with the exception of those marked with an asterisk (*).

ABS

Anti-lock Brake System

MAF

Mass Air Flow

BJB*

Battery Junction Box

NTC*

Negative Temperature Coefficient

CHT*

Cylinder Head Temperature

O/D*

Overdrive

CJB*

Central Junction Box

OSS

Output Shaft Speed

CKP

Crankshaft Position

PATS*

Passive Anti-Theft System

DLC

Data Link Connector

PCM

Powertrain Control Module

EEC V*

Electronic Engine Control, 5th Generation

PWM*

Pulse Width Modulation

ESSC*

Electronic Synchronous Shift Control

SCP*

Standard Corporate Protocol

IAT

Intake Air Temperature

SS

Shift Solenoid

IFS

Inertia Fuel Shutoff

TCC

Torque Converter Clutch

KOEO*

Key On, Engine Off

TFT

Transmission Fluid Temperature

KOER*

Key On, Engine Running

60

Service Training

List of abbreviations TP

Throttle Position

TR

Transmission Range

TSS

Turbine Shaft Speed

VSS

Vehicle Speed Sensor

WDS*

Worldwide Diagnostic System

WOT

Wide Open Throttle

Service Training

61

Answers to the test questions Lesson 1 – Preliminary checks

Lesson 4 – Actuators

1.

b

1.

b

2.

c

2.

c

3.

d

3.

a

4.

b

5.

b

Lesson 2 – Transaxle control 1.

d

2.

b

Lesson 5 – Diagnostic instructions

3.

c

1.

a

4.

b

2.

b

5.

a

3.

b

4.

c

Lesson 3 – Sensors 1.

d

2.

b

3.

a

4.

c

5.

a

62

Service Training

Notes

Service Training

63

Notes

64

Service Training