Lexus ES300 (1997 year). Manual — part 397

N14677

Fuse

W02760

AB0119

H00048

Airbag Sensor Assembly

ON

LA

(–)

(+)

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–365

517

1997 LEXUS ES300 (RM511U)

INSPECTION PROCEDURE

1

Check ECU–B Fuse.

PREPARATION:
Remove ECU–B fuse.
CHECK:
Check continuity of ECU–B fuse.
OK:

Continuity

HINT:

Fuse may be burnt out even if it appears to be OK during
visual inspection.

If fuse is OK, install it.

NG

Go to step ” 5 ”.

OK

2

Preparation. (See step ” 1 ” on page

DI–359

)

3

Check SRS warning light circuit.

PREPARATION:
(a)

Connect negative (–) terminal cable to battery.

(b)

Turn ignition switch to ACC or ON.

CHECK:
Measure voltage LA terminal of harness side connector of air-
bag sensor assembly.
OK:

Voltage: 10 – 14 V

NG

Check SRS warning light bulb / repair SRS
warning light circuit.

OK

H00078

Airbag Sensor
Assembly

P Squib

D Squib

Spiral
Cable

ON

DI–366

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

518

1997 LEXUS ES300 (RM511U)

4

Does SRS warning light come on?

PREPARATION:
(a)

Disconnect negative (–) terminal cable from the battery.

(b)

Connect airbag sensor assembly connector.

(c)

Connect negative (–) terminal cable to battery, and wait
at least 2 seconds.

(d)

Turn ignition switch to ACC or ON.

CHECK:
Check operation of SRS warning light.

NO

Check terminal LA of airbag sensor assembly.
If normal, replace airbag sensor assembly.

YES

From the results of the above inspection, the malfunctioning part can now be considered normal.
To make sure of this, use simulation method to check.

5

Is new ECU–B fuse burnt out again?

NO

Using simulation method, reproduce malfunc-
tion symptoms (See page

IN–17

).

YES

Check harness between ECU–B fuse and
SRS warning light.

W04367

Airbag Sensor
Assembly

Tc

4

B

B

LG–R

J1 Junction
Connector

LG–R

Tc

DLC1

W–B

E1

A

A

A

P–B

ED

1J

10

8

11

LG–R

BR

1K3

II

B

1N

W–B

B

11

Tc E1

3

A

BR

ED

J24
Junction
Connector

E1

3

BR

J8

J9

BR

IK3

BR

A

A

6

C

DLC2

J24
Junction
Connector

JB
Junction
Connector

BR

J15
Junction
Connector

Instrument
Panel J/B

1

1

AB0117 AB0118 AB0119

H00079

LOCK

ACC

ON

or

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–367

519

1997 LEXUS ES300 (RM511U)

Tc Terminal Circuit

CIRCUIT DESCRIPTION

By connecting terminals Tc and E1 of the DLC1 the airbag sensor assembly is set in the DTC output mode.
The DTCs are displayed by the blinking of the SRS warning light.

WIRING DIAGRAM

INSPECTION PROCEDURE

If the DTC is not displayed, do the following troubleshooting.

1

Does SRS warning light up for approx. 6 seconds?

PREPARATION:
Check operation of SRS warning light after ignition switch is
turned from LOCK position to ACC or ON position.

DI0BA–01

AB0118

R14305

AB0119

H00030

ACC

ON

or

E1

Tc

(+)

(–)

AB0118

R14304

AB0119

H00031

ACC

ON

or

Tc

(+)

(–)

DI–368

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

520

1997 LEXUS ES300 (RM511U)

NO

Check SRS warning light system
(See page

DI–324

).

YES

2

Check voltage between terminals Tc and E1 of DLC1.

PREPARATION:
Turn ignition switch to ACC or ON.
CHECK:
Measure voltage between terminals Tc and E1 of DLC1.
OK:

Voltage; 10 – 14 V

OK

Go to step ” 4 ”.

NG

3

Check voltage between terminals Tc of DLC1 and body ground

CHECK:
Measure voltage between terminal Tc of DLC1 and body
ground.
OK:

Voltage: 10 – 14 V

OK

Check harness between terminal E1 of DLC1
and body ground.

NG