Get INTRODUCTION -> How to Troubleshoot ECU Controlled Systems Guide for Toyota Avensis 4 Door First Generation (1997-2003)

IN–19

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS

IN00Z–45

GENERAL INFORMATION

A large number of ECU controlled systems are used in the AVENSIS/CORONA. In general, the ECU con-

trolled system is considered to be a very intricate system requiring a high level of technical knowledge and

expert skill to troubleshoot. However, the fact is that if you proceed to inspect the circuits one by one, trouble-

shooting of these systems is not complex. If you have adequate understanding of the system and a basic

knowledge of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the

problem. This manual is designed through emphasis of the above standpoint to help service technicians

perform accurate and effective troubleshooting, and is compiled for the following major ECU controlled sys-

tems:

The troubleshooting procedure and how to make use of it are described on the following pages.

System

Page

DI–1

1. AutomaticTransaxle(A246E)

2. AutomaticTransaxle(U240E)

DI–60

DI–127

DI–169

DI–255

3. Anti–Lock Brake System with Electronic Brake Force Distribution (EBD)

4. ABS with EBD & BA & TRC & VSC System

5. EngineImmobiliserSystem

FOR USING HAND–HELD TESTER

S

Before using the hand–held tester, the hand–held tester’s operator manual should be read thoroughly.

If the hand–held tester cannot communicate with ECU controlled systems when you have connected

the cable of the hand–held tester to DLC3, turned the ignition switch ON and operated the scan tool,

there is a problem on the vehicle side or tool side.

S

(1) If communication is normal when the tool is connected to another vehicle, inspect the diagnosis

data link line (Busęline) or ECU power circuit of the vehicle.

(2) If communication is still not possible when the tool is connected to another vehicle, the problem

is probably in the tool itself, so perform the Self Test procedures outline in the Tester Operator’s

Manual.

AVENSIS/CORONA SUP (RM781E)

IN–20

INTRODUCTION

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HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

IN06D–10

HOW TO PROCEED WITH TROUBLESHOOTING

Carry out troubleshooting in accordance with the procedure on the following page. Here, only the basic pro-

cedure is shown. Details are provided in DI section, showing the most effective methods for each circuit.

Confirm the troubleshooting procedures first for the relevant circuit before beginning troubleshooting of that

circuit.

Vehicle Brought to Workshop

1

Ask the customer about the conditions and the

environment when the problem occurred.

1

Customer Problem

Analysis

3

2

Symptom Confirmation

and Diagnostic Trouble

Code Check

Symptom Simulation

2, 3

Confirm the symptoms and the problem conditions,

and check the diagnostic trouble codes.

(When the problem symptoms do not appear

during confirmation, use the symptom simulation

method described later on.)

4

Diagnostic Trouble

Code Chart

5

Problem Symptoms Table

4, 5, 6

Check the results obtained in Step 2, then confirm

the inspection procedure for the system or the part

which should be checked using the diagnostic

trouble code chart or the problem symptoms table.

6

Circuit Inspection or Parts

Inspection

7

8

Check and repair the affected system or part in

accordance with the instructions in Step 6.

Repair

8

Confirmation Test

End

After completing repairs, confirm that the problem

has been eliminated.

(If the problem is not reproduced, perform the

confirmation test under the same conditions and

in the same environment as when it occurred for

the first time.)

AVENSIS/CORONA SUP (RM781E)

IN–21

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

1.

CUSTOMER PROBLEM ANALYSIS

In troubleshooting, the problem symptoms must be confirmed accurately and all preconceptions must be

cleared away in order to give an accurate judgement. To ascertain just what the problem symptoms are, it

is extremely important to ask the customer about the problem and the conditions at the time it occurred.

Important Point in the Problem Analysis:

The following 5 items are important points in the problem analysis. Past problems which are thought to be

unrelated and the repair history, etc. may also help in some cases, so as much information as possible should

be gathered and its relationship with the problem symptoms should be correctly ascertained for reference

in troubleshooting. A customer problem analysis table is provided in DI section for each system for your use.

Important Points in the Customer Problem Analysis

D What ––––– Vehicle model, system name

D When ––––– Date, time, occurrence frequency

D Where ––––– Road conditions

D Under what conditions? ––––– Running conditions, driving conditions, weather conditions

D How did it happen? ––––– Problem symptoms

(Sample) Supplemental restraint system check sheet.

CUSTOMER PROBLEM ANALYSIS CHECK

Inspector’s

Supplemental Restraint System Check Sheet

Name

RegistrationNo.

RegistrationYear

/

Customer’s Name

Frame No.

km

miles

OdometerReading

DateVehicleBroughtIn

/

Date Problem First Occurred

Weather

Other

Fine

Cloudy

Rainy

Snowy

Approx.

Temperature

Starting

Driving

Idling

Constantspeed

Other

VehicleOperation

[

Acceleration

Deceleration

]

AVENSIS/CORONA SUP (RM781E)

IN–22

2.

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK

The diagnostic system in the AVENSIS/CORONA fulfills various functions. The first function is the Diagnostic

Trouble Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the ECU

memory at the time of occurrence, to be output by the technician during troubleshooting. Another function

is the Input Signal Check which checks if the signals from various switches are sent to the ECU correctly.

By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can

be performed effectively. Diagnostic functions are incorporated in the following systems in the AVENSIS/CO-

RONA.

Diagnostic Trouble

Code Check

Input Signal Check

(Sensor Check)

Diagnostic Test

System

Mode (Active Test)

f

1. AutomaticTransaxle(A246E)

2. AutomaticTransaxle(U240E)

f

(with check mode)

f

(with check mode)

3. Anti–Lock Brake System with Electronic Brake Force Distribution (EBD)

4. ABS with EBD & BA & TRC & VSC System

5. EngineImmobiliserSystem

f

In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-

nostic trouble code is still occurring or occurred in the past but returned to normal at present. In addition,

it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic

trouble code is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes

should be checked before and after the symptom confirmation to determine the current conditions, as shown

in the table below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting

for normally operating systems, thus making it more difficult to locate the problem, or in repairs not pertinent

to the problem. Therefore, always follow the procedure in correct order and perform the diagnostic trouble

code check.

DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE

Diagnostic Trouble

Code Check (Make a

note of and then clear)

Confirmation

of Symptoms

Diagnostic Trouble

Code Check

Problem Condition

Problem symptoms Same diagnostic

Diagnostic Trouble

Code Display

Problem is still occurring in the diagnostic

circuit

exist

trouble code is

displayed

Normal code is

displayed

The problem is still occurring in a place

other than in the diagnostic circuit

(The diagnostic trouble code displayed

first is either for a past problem or it is a

secondary problem)

No problem

symptoms exist

The problem occurred in the diagnostic

circuit in the past

The problem is still occurring in a place

other than in the diagnostic circuit

Problem symptoms Normal code is

Normal Code Display

exist

displayed

No problem

symptoms exist

Normal code is

displayed

The problem occurred in a place other

than in the diagnostic circuit in the past

AVENSIS/CORONA SUP (RM781E)

IN–23

INTRODUCTION

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HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

Taking into account the above points, a flow chart showing how to proceed with troubleshooting using the

diagnostic trouble code check is shown below. This flow chart shows how to utilize the diagnostic trouble

code check effectively, then by carefully checking the results, indicates how to proceed either to diagnostic

trouble code troubleshooting or to troubleshooting of problem symptoms.

Diagnostic trouble code check

Making a note of and clearing of the diagnostic trouble codes displayed

Symptom confirmation

No problem symptoms

Problem symptoms

exist

Simulation test using the symptom

simulation methods

Diagnostic trouble code check

D Diagnostic trouble code displayed

D Problem symptoms exist

D Normal code displayed

D Problem symptoms exist

D No problem symptoms exist

Troubleshooting of each

problem symptom

Troubleshooting of problem indicated

by diagnostic trouble code

System Normal

If a diagnostic trouble code was

displayed in the initial diagnostic

trouble code check, it indicates

that the trouble may have occurred

in a wire harness or connector in

that circuit in the past. Therefore,

check the wire harness and con-

nectors (See page IN–30).

AVENSIS/CORONA SUP (RM781E)

IN–24

3.

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

SYMPTOM SIMULATION

The most difficult case in troubleshooting is when there are no problem symptoms occurring. In such cases,

a thorough customer problem analysis must be carried out, then simulate the same or similar conditions and

environment in which the problem occurred in the customer’s vehicle. No matter how much experience a

technician has, or how skilled he or she may be, if he or she proceeds to troubleshoot without confirming

the problem symptoms he or she will tend to overlook something important in the repair operation and make

a wrong guess somewhere, which will only lead to a standstill. For example, for a problem which only occurs

when the engine is cold, or for a problem which occurs due to vibration caused by the road during driving,

etc., the problem can never be determined so long as the symptoms are confirmed with the engine hot condi-

tion or the vehicle at a standstill. Since vibration, heat or water penetration (moisture) is likely cause for prob-

lem which is difficult to reproduce, the symptom simulation tests introduced here are effective measures in

that the external causes are applied to the vehicle in a stopped condition.

Important Points in the Symptom Simulation Test:

In the symptom simulation test, the problem symptoms should of course be confirmed, but the problem area

or parts must also be found out. To do this, narrow down the possible problem circuits according to the symp-

toms before starting this test and connect a tester beforehand. After that, carry out the symptom simulation

test, judging whether the circuit being tested is defective or normal and also confirming the problem symp-

toms at the same time. Refer to the problem symptoms table for each system to narrow down the possible

causes of the symptom.

1

VIBRATION METHOD: When vibration seems to be the major cause.

CONNECTORS

Slightly shake the connector vertically and horizontally.

Shake Slightly

WIRE HARNESS

Slightly shake the wire harness vertically and horizontally.

The connector joint, fulcrum of the vibration, and body

through portion are the major areas to be checked thorough-

ly.

Swing Slightly

PARTS AND SENSOR

Vibrate Slightly

Apply slight vibration with a finger to the part of the sensor

considered to be the problem cause and check that the mal-

function occurs.

HINT:

Applying strong vibration to relays may result in open relays.

V07268

AVENSIS/CORONA SUP (RM781E)

IN–25

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

2

HEAT METHOD: When the problem seems to occur when the suspect area is heated.

Heat the component that is the likely cause of the malfunction

with a hair dryer or similar object. Check to see if the malfunction

occurs.

Malf unc-

tion

NOTICE:

(1)

Do not heat to more than 60 °C (140 °F). (Temperature

is limited not to damage the components.)

(2)

Do not apply heat directly to parts in the ECU.

When the malfunction seems to occur on a rainy day or in a

high–humidity condition.

3

WATER SPRINKLING METHOD:

Sprinkle water onto the vehicle and check to see if the malfunc-

tion occurs.

NOTICE:

(1) Never sprinkle water directly into the engine compart-

ment, but indirectly change the temperature and hu-

midity by applying water spray onto the radiator front

surface.

(2) Never apply water directly onto the electronic compo-

nents.

HINT:

If a vehicle is subject to water leakage, the leaked water may

contaminate the ECU. When testing a vehicle with a water leak-

age problem, special caution must be taken.

4

OTHER: When a malfunction seems to occur when electrical load is excessive.

Turn on all electrical loads including the heater blower, head

lights, rear window defogger, etc. and check to see if the mal-

function occurs.

ON

B02389

B02390

AVENSIS/CORONA SUP (RM781E)

IN–26

4.

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

DIAGNOSTIC TROUBLE CODE CHART

The inspection procedure is shown in the table below. This table permits efficient and accurate troubleshoot-

ing using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with trouble-

shooting in accordance with the inspection procedure given in the diagnostic chart corresponding to the

diagnostic trouble codes displayed. The Supplemental Restraint System diagnostic trouble code chart is

shown below as an example.

D DTC No.

Indicates the diagnostic trouble code.

Page or Instructions

D

Trouble Area

Indicates the suspect area of the

problem.

Indicates the page where the inspection procedure

for each circuit is to be found, or gives instructions

for checking and repairs.

D

Detection Item

Indicates the system of the problem or

contents of the problem.

DIAGNOSTIC TROUBLE CODE CHART

If a malfunction code is displayed during the DTC check, check the circuit listed for that code in the table

below. (Proceed to the page given for that circuit).

DTC No.

SRS

WarmingLight

DetectionItem

TroubleArea

(Seepage)

Short in D squib circuit (to ground)

D Steering wheel pad (squib)

11

D Spiral cable

ON

(DI–165)

D Airbag sensor assembly

D Wire harness

Short in D squib circuit (to B))

Short in D squib circuit

D Steering wheel pad (squib)

D Spiral cable

12

ON

(DI–170)

D Airbag sensor assembly

D Wire harness

D Steering wheel pad (squib)

D Spiral cable

13

(DI–174)

D Airbag sensor assembly

D Wire harness

Open in D squib circuit

D Steering wheel pad (squib)

D Spiral cable

14

ON

D Airbag sensor assembly

(DI–178)

D Wire harness

15

Front airbag sensor assembly (RH)

malfunction

D Front airbag sensor assembly (RH)

D Wire harness

(DI–178)

16

Front airbag sensor assembly (LH)

malfunction

D Front airbag sensor assembly (LH)

ON

D Wire harness

airbag sensor assembly malfunction

Airbag sensor assembly

ON

Short in P squib circuit (to ground)

D Front passenger airbag sensor assembly (squib)

D Airbag sensor assembly

AVENSIS/CORONA SUP (RM781E)

IN–27

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

5.

PROBLEM SYMPTOMS TABLE

The suspected circuits or parts for each problem symptom are shown in the table below. Use this table to

troubleshoot the problem when a ”Normal” code is displayed in the diagnostic trouble code check but the

problem is still occurring. Numbers in the table indicate the inspection order in which the circuits or parts

should be checked.

HINT:

When the problem is not detected by the diagnostic system even though the problem symptom is present,

it is considered that the problem is occurring outside the detection range of the diagnostic system, or that

the problem is occurring in a system other than the diagnostic system.

Page

D

Indicates the page where the flow chart for each circuit

is located.

D

Circuit Inspection, Inspection Order

Indicates the circuit which needs to be checked for each problem

symptom. Check in the order indicated by the numbers.

D

Circuit or Part Name

Indicates the circuit or part which needs to be checked.

D Problem Symptom

PROBLEM SYMPTOMS TABLE

Proceed with troubleshooting of each circuit in the table below.

See page

DI–288

Symptom

Suspect Area

D WiththeignitionswitchintheACCorONposition,theSRSwarning

lightsometimes lights up after approx. 6 seconds have elapsed.

D SRS warning light is always lit up even when ignition switch is in

the LOCK position

D SRS warning light circuit

(Always lights up when ignition switch is in

LOCKposition.)

D SRS warning light circuit

D WiththeignitionswitchintheACCorONposition,theSRSwarning

DI–290

DI–294

(Dose not light up when ignition switch is turned to

ACC or ON.)

lightdoes not light up.

D DTC is not displayed.

D

SRS warning light is always lit up at the time of DTC check

D Tc terminal circuit

procedure.

D DTC is displayed without Tc and E1 terminal connection.

AVENSIS/CORONA SUP (RM781E)

IN–28

6.

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

CIRCUIT INSPECTION

How to read and use each page is shown below.

D Diagnostic Trouble Code No. and Detection Item

D

Circuit Description

The major role and operation, etc. of the circuit

and its component parts are explained.

DTC

13

Short in D Squib Circuit

CIRCUIT DESCRIPTION

The D squib circuit consists of the airbag sensor assembly, spiral cable and steering wheel pad.

It causes the airbag to deploy when the airbag deployment conditions are satisfied.

For details of the function of each components,see OPERATION on page RS–2.

DTC 13 is recorded when a short is detected in the D squib circuit.

DTC Detecting Condition

Trouble Area

DTC No.

SShort circuit between D) wire harness and D* wire harness of squib SSteering wheel pad (D squib)

SD squib malfunction

SSpiral cable

SAirbag sensor assembly

SWire harness

13

SSpiral cable malfunction

SAirbag sensor assembly malfunction

D

Indicates the diagnostic trouble code, diagnostic

trouble code set parameter and suspect area of

the problem.

WIRING DIAGRAM

D

Wiring Diagram

This shows a wiring diagram of the circuit.

Use this diagram together with ELECTRICAL

WIRING DIAGRAM to thoroughly understand the

circuit.

Airbag Sensor

Assembly

Wire colors are indicated by an alphabetical code.

B = Black, L = Blue, R = Red, BR = Brown,

LG = Light Green, V = Violet, G = Green,

O = Orange, W = White, GR = Gray, P = Pink,

Y = Yellow

1

G–R

G–Y

7

6

+

A15

D

Spiral

Cable

D Squib

–

A15

D

2

The first letter indicates the basic wire color and

the second letter indicates the color of the stripe.

R16015

B02407

AVENSIS/CORONA SUP (RM781E)

IN–29

INTRODUCTION

–

HOW TO TROUBLESHOOTECU CONTROLLED

SYSTEMS

D Indicates the position of the ignition switch during the check. D Inspection Procedure

Use the inspection procedure to determine

if the circuit is normal or abnormal, and if it

is abnormal, use it to determine whether the

problemis located in the sensors, actuators,

wire harness or ECU.

ON

LOCK

Ignition Switch ON

IgnitionSwitch LOCK (OFF)

START

ACC

Ignition Switch ACC

Ignition Switch START

INSPECTION PROCEDURE

2

Check voltage at IG2 and ACC of airbag sensor assembly.

PREPARATION:

Turn ignition switch ON.

CHECK:

ON

AirbagSensor Assembly

Measure voltage between terminals IG2 and ACC of

airbag sensor assembly and body ground.

ACC

(+)

IG2

(–)

OK:

AB0119

W02766

Voltage: Below 16V

H00041

Check battery and charging system.

(See charging system section)

NG

OK

D Indicates the place to check the voltage or resistance.

D Indicates the connector position to be checked, from the front or back side.

Wire Harness

Check from the connector front side. (without harness)

In this case, care must be taken not to bend the terminals.

Check from the connector back side.

(with harness)

D Indicates the condition of the connector of ECU during the check.

KNK

E6 Connector

Connector being checked is disconnected.

Connector being checked is connected.

B00691

B00972

AVENSIS/CORONA SUP (RM781E)

INTRODUCTION -> How to Troubleshoot ECU Controlled Systems for Your Toyota Avensis 4 Door First Generation (1997-2003)

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