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Lexus ES300 (2002 year). Manual - part 278

Detection Item
Indicates the system of the problem or
contents of the problem.

Trouble Area
Indicates the suspect area of
the problem.

Detection Item

DTC No.

(See page)

Trouble Area

SRS

Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness

B0103/12

(05-132)

B0102/11

(05-128)

DIAGNOSTIC TROUBLE CODE CHART

If a malfunction code is displayed during the DTC check, check the circuit for that code listed in the table
below (Proceed to the page given for that circuit).

Short in D squib circuit

Open in D squib circuit

B0101/14

(05-124)

Short in D squib circuit (to ground)

Short in D squib circuit (to B+)

Warming Light

Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness

Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness

Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness

B0105/53

(05-136)

Airbag sensor assembly

Wire harness

B0106/54

Open in P squib circuit

Airbag sensor assembly

Wire harness

Short in P squib circuit (to Ground)

B0100/13

(05-1 19)

Short in P squib circuit

Front passenger airbag assembly (squib)

Airbag sensor assembly

Wire harness

Front passenger airbag assembly (squib)

DTC No.
Indicates the diagnostic trouble code.

01-28

INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

DIAGNOSTIC TROUBLE CODE CHART

The inspection procedure is shown in the table below. This table permits an efficient and accurate trouble-
shooting using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with
troubleshooting 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.

INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

01-29

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

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.

Symptom

Suspected Area

See page

1. With the ignition switch in ACC or ON position, the SRS warning

light sometimes lights up after approx. 6 seconds have elapsed.

2. SRS warning light is always lit up even when ignition switch is

in the LOCK position

1. With the ignition switch in the ACC or ON position, the SRS

warning light does not light up.

PROBLEM SYMPTOMS TABLE

1. DTC is not displayed.

05-187

05-183

Problem Symptom

Circuit Inspection, Inspection Order
Indicates the circuit which needs to be checked for each problem
symptom. Check in the order indicated by the numbers.

Circuit or Part Name
Indicates the circuit or part which needs to be checked.

Proceed with troubleshooting of each circuit in the table below.

1. SRS warning light circuit

(Always lights up when ignition switch is in

LOCK position.)

1. SRS warning light circuit

(Does not light up when ignition switch is turned

to ACC or ON.)

1. Tc terminal circuit

05-180

3. DTC is displayed without Tc and CG terminal connection.

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

procedure.

SFI

D25842

Circuit Description

The major role and operation, etc. of the circuit
and its component parts are explained.

Diagnostic Trouble Code No. and Detection Item

Indicates the diagnostic trouble code, diagnostic

trouble code set parameter and suspect area of
the problem.

Wiring Diagram
This shows a wiring diagram of the circuit.
Use this diagram together with ELECTRICAL
WIRING DIAGRAM to thoroughly understand the
circuit.
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, SB = Sky Blue
The first letter indicates the basic wire color and
the second letter indicates the color of the stripe.

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
problem is located in the sensors, actuators,
wire harness or ECU.

Indicates the condition of the connector of ECU during

the check.

Connections of tester are
indicated by (+), (-) after
terminals name.

Connector being checked
is connected.

On inspection with body
ground side is not speci-
fied.

Connector being checked
is disconnected.

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INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

CIRCUIT INSPECTION

How to read and use each page is shown below.

01046-03

D25086

WRONG

CORRECT

D25087

Looseness of Crimping

Core Wire

Terminal
Deformation

Pull Lightly

INTRODUCTION

HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS

01-31

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

ELECTRONIC CIRCUIT INSPECTION PROCEDURE

BASIC INSPECTION

(a)

RESISTANCE MEASURING CONDITION OF ELECTRONIC PARTS
(1)

Unless stated, all resistance is measured at an ambient temperature of 20

C (68

F). Because

the resistance may be outside the specifications if measured at high temperatures immediately
after the vehicle has been running, measurements should be made when the engine has cooled
down.

(b)

HANDLING OF CONNECTOR
(1)

When removing the connector with a lock, press the
connector toward the engagement and remove the
lock by making the lock claw movable easily.

(2)

When removing the connector, do not hold the har-
ness, but hold the connector.

(3)

Before connecting the connector, check that there
are no deformation, damage and missing of the ter-
minals.

(4)

Connection of the connector with a lock should be
securely done until it makes a click sound.

(5)

In case of checking the connector with a Toyota
electrical tester, perform it at the back side (harness
side) of the connector using a mini test lead.

NOTICE:

As a water proof connector cannot be checked from
its back side, check by connecting the sub-harness.

Do not damage the terminals by moving the inserted
tester needle.

(c)

CONNECTOR CHECKING POINTS
(1)

Checking when the connector is connected:
By holding the connector, check the inserted condi-
tion and locking efficiency (engaged condition).

(2)

Checking when the connector is removed:
Check the wire harness by pulling lightly (missing
terminal, terminal crimping condition, core wire
break).
Check visually if there is any rust, metal tip, water
and bend of terminal (rust, mixing of foreign object,
terminal deformation).

NOTICE:
When testing a gold-plated female terminal, always use a
gold-plated male terminal.

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