Lexus ES300 (1997 year). Service manual - part 395

R05898

R14287

H00045

P–

P+

(–)

(+)

D Squib

P Squib

Airbag Sensor
Assembly

Spiral
Cable

AB0069

AB0118

R13006

W01934

AB0119

W02045

H00024

P+

P–

Airbag Sensor
Assembly

P Squib

D Squib

Spiral
Cable

ACC

ON

or

DLC1

E1

Tc

Code 54

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–357

509

1997 LEXUS ES300   (RM511U)

2

Check P squib circuit.

CHECK:
For the connector (on the airbag sensor assembly side) be-
tween the airbag sensor assembly and front passenger airbag
assembly measure the resistance between P+ and P–.
OK:

Resistance: Below 1 

Ω

NG

Repair or replace harness or connector be-
tween airbag sensor assembly and front pas-
senger airbag assembly.

OK

3

Check airbag sensor assembly.

PREPARATION:
(a)

Connect connector to airbag sensor assembly.

(b)

Using a service wire, connect P+ and P– on airbag sensor
assembly side of connector between airbag sensor as-
sembly and front passenger airbag assembly.

(c)

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

CHECK:
(a)

Turn ignition switch to ACC or ON and wait at least 20 se-
conds.

(b)

Clear malfunction code stored in memory
(See page 

DI–324

).

(c)

Turn ignition switch to LOCK, and wait at least 20 se-
conds.

(d)

Turn ignition switch to ACC or ON, and wait at least 20 se-
conds.

(e)

Using SST, connect terminal Tc and E1 of DLC1.
SST 09843–18020

(f)

Check DTC.

OK:

DTC 54 is not output.

HINT:
Codes other than code 54 may be output at this time, but they
are not relevant to this check.

R05909

AB0118

R13006

AB0119

W02045

H00025

Airbag Sensor
Assembly

P Squib

D Squib

Spiral
Cable

ACC

ON

or

DLC1

E1

Tc

Code 54

DI–358

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

510

1997 LEXUS ES300   (RM511U)

NG

Replace airbag sensor assembly.

OK

4

Check P squib.

PREPARATION:
(a)

Turn ignition switch to LOCK.

(b)

Disconnect negative (–) terminal cable from the battery,
and wait at least 90 seconds.

(c)

Connect front passenger airbag assembly connector.

(d)

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

CHECK:
(a)

Turn ignition switch to ACC or ON and wait at least 20 se-
conds.

(b)

Clear malfunction code stored in memory
(See page 

DI–324

).

(c)

Turn ignition switch to LOCK, and wait at least 20 se-
conds.

(d)

Turn ignition switch to ACC or ON, and wait at least 20 se-
conds.

(e)

Using SST, connect terminal Tc and E1 of DLC1.
SST 09843–18020

(f)

Check DTC.

OK:

DTC 54 is not output.

HINT:
Codes other than code 54 may be output at this time, but they
are not relevant to this check.

NG

Replace front passenger airbag assembly.

OK

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

W04365

Airbag
Sensor
Assembly

Ignition Switch

Battery

2

1

5A

3

7

6

3

6

1

W–R

L–R

B–R

ACC

IG2

ALT

AM1

AM2

CIG

IGN

1N

1K

1N

1K

ACC

IG1

IG2

ST2

AM1

AM2

4

J15
Junction
connector

Instrument
Panel J/B

W

5

B–R

1B

1K

1K

1B

1

5

2A

100A

4

W–R

B

2

1

2

W–B

B–R

B–G

Engine 
Room J/B

FL MAIN
3.0 W

Fusible Link
Block

15

16

II

E1

F11

F6

F8

2L

Instrument
Panel J/B

GR

Instrument
Panel J/B

1N

1J

W–B

15A

30A

40A

10

1

1

2

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–359

511

1997 LEXUS ES300   (RM511U)

DTC

Normal

Source Voltage Drop

CIRCUIT DESCRIPTION

The SRS is equipped with a voltage–increase circuit (DC–DC converter) in the airbag sensor assembly in
case the source voltage drops.
When the battery voltage drops, the voltage–increase circuit (DC–DC converter) functions to increase the
voltage of the SRS to normal voltage.
The diagnosis system malfunction display for this circuit is different to other circuits–when the SRS warning
light remains lit up and the DTC is a normal code, source voltage drop is indicated.
Malfunction in this circuit is not recorded in the airbag sensor assembly, and the source voltage returns to
normal, the SRS warning light automatically goes off.

DTC No.

Diagnosis

(Normal)

Source voltage drop.

WIRING DIAGRAM

DI0B7–01

R05894

AB0117

H00001

Airbag Sensor 
Assembly

LOCK

Spiral
Cable

D Squib

P Squib

AB0119

W02766

H00041

ON

Airbag Sensor Assembly

ACC

IG2

(+)

(–)

DI–360

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

512

1997 LEXUS ES300   (RM511U)

INSPECTION PROCEDURE

1

Preparation.

PREPARATION:
(a)

Disconnect negative (–) terminal cable from the battery,
and wait at least 90 seconds.

(b)

Remove steering wheel pad (See page 

SR–11

).

(c)

Disconnect connector of front passenger airbag assem-
bly (See page 

RS–21

).

(d)

Disconnect connector of airbag sensor assembly 
(See page 

RS–35

).

CAUTION:
Store the steering wheel pad with the front surface facing
upward.

2

Check source voltage.

PREPARATION:
(a)

Connect negative (–) terminal cable to battery.

(b)

Turn ignition switch ON.

CHECK:
Measure voltage at IG2 or ACC on sensor and operate electric
system. (defogger, wiper, headlight, heater blower, etc.)
OK:

Voltage: 10 – 14 V

NG 

Check the harness between battery and airbag
sensor assembly, and check the battery and
charging system.

OK