Lexus ES300 (2002 year). Manual — part 276

01044-03

01-20

-

INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

20

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS

GENERAL INFORMATION

A large number of ECU controlled systems are used in LEXUS ES300. In general, the ECU controlled system
is considered to be a very intricate system requiring high level of technical knowledge and expert skill to trou-
bleshoot. The fact is, however, that if you proceed to inspect the circuits one by one, troubleshooting of these
systems is not complex. If you have adequate understanding of the system and basic knowledge of electric-
ity, 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 an accurate and
effective troubleshooting, and is compiled for the following major ECU controlled systems.
The troubleshooting procedure and how to make use of it are described on the following pages.

System

Page

1. SFI System

05-1

2. Electronic Modulated Suspension System

05-190

3. ABS with EBD System

05-236

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

05-284

5. Electronic Controlled Automatic Transmission [ECT]

05-384

6. Air Conditioning System

05-455

7. Supplemental Restraint System

05-543

8. Lighting System

05-750

9. Wiper and Washer System

05-810

10.Audio System

05-820

11.LEXUS Navigation System

05-886

12.Power Window Control System

05-973

13.Power Mirror Control System

05-1024

14.Combination Meter

05-1040

15.Front Power Seat Control System (with memory)

05-1081

16.Power Door Lock Control System

05-1095

17.Wireless Door Lock Control System

05-1 129

18.Luggage Comportment Door Opener System

05-1 152

19.Key Unlock Warning System

05-1 167

20.Engine Immobiliser System

05-1 180

21.Theft Deterrent System

05-1 197

22.Multiplex Communication System

05-1213

23.Cruise Control System

05-1243

FOR USING OBDII SCAN TOOL OR HAND-HELD TESTER
HINT:

Before using the scan tools or tester, the scan tool’s instruction book or tester’s operator manual should
be read thoroughly.

If the scan tool or tester cannot communicate with the ECU controlled systems when you have con-
nected the cable of the scan tool or tester to the DLC3 with the ignition switch and tester turned ON,
there is a problem on the vehicle side or tester side.
(1)

If the communication is normal when the tester is connected to another vehicle, inspect the diag-
nosis data link line (Bus

line) or ECU power circuit of the vehicle.

(2)

If the communication is still impossible when the tester is connected to another vehicle, the prob-
lem is probably in the tester itself, so perform the Self Test procedures outlined in the Tester Oper-
ator’s Manual.

01045-03

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INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

01-21

21

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

HOW TO PROCEED WITH TROUBLESHOOTING

HINT:
Carry out a troubleshooting in accordance with the procedure on the following page. Here, only the basic
procedure is shown. Details are provided in the Diagnostics section, showing the most effective methods
for each circuit. Confirm the troubleshooting procedures first for the relevant circuit before beginning the trou-
bleshooting of that circuit.

1

Vehicle brought to workshop

2

Customer problem analysis

(a)

Ask the customer about the conditions and environment when the problem occurred.

3

Symptom confirmation and DTC (and freeze frame data) check

(a)

Check the battery positive voltage.
Voltage: 10 - 14 V (Engine stopped)

(b)

Visually check the wire harness, connectors and fuses for open and short, etc.

(c)

Warm up the engine to the normal operating temperature.

(d)

Confirm the problem symptoms and conditions, and check the DTCs according to the applicable chart.

OK

Go to step 5

NG

4

DTC chart

(a)

Check the results obtained in step 3, then confirm the inspection procedure for the system or the part
which should be checked using the DTC chart.

Go to step 6

5

Problem symptoms chart

(a)

Check the results obtained in step 3, then confirm the inspection procedure for the system or the part
which should be checked using the problem symptoms table.

6

Circuit inspection or parts inspection

(a)

Confirm the circuit for the system or the part which should be checked using the problem symptoms
table or the results obtained in step 4.

7

Repair

(a)

Repair the affected system or part in accordance with the instructions in step 6.

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INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

22

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

8

Confirmation test

(a)

After completing repairs, confirm that the problem has been solved.
(If the problem dose not reoccur, perform a confirmation test under the same conditions and in the
same environment as when it occurred for the first time.)

END

Important Points in the Customer Problem Analysis

What ----- Vehicle model, system name

When ----- Date, time, occurrence frequency

Where ----- Road conditions

Under what conditions? ----- Running conditions, driving conditions, weather conditions

How did it happen? ----- Problem symptoms

(Sample) Supplemental restraint system check sheet.

Supplemental Restraint System Check Sheet

Customer’s Name

Date Vehicle Brought In

Registration No.

Frame No.

Odometer Reading

km
miles

Date Problem First Occurred

Weather

Temperature

Vehicle Operation

Fine

Cloudy

Starting

Idling

Driving

Constant speed

Acceleration

Other

Inspector’s
Name

CUSTOMER PROBLEM ANALYSIS CHECK

Registration Year

Rainy

Snowy

Other

/ /

/ /

/ /

Approx.

Deceleration

[

]

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INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

01-23

23

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

CUSTOMER PROBLEM ANALYSIS

HINT:

In troubleshooting, the problem symptoms must be confirmed accurately and all preconceptions must
be cleared in order to give an accurate judgment. To ascertain what the problem symptoms are, it is
extremely important to ask the customer about the problem and conditions when it occurred.

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 ascer-
tained for a reference in troubleshooting. A customer problem analysis table is provided in Diagnostics
section for each system for your use.

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Политика конфиденциальности