Lexus RX300 (MCU15). Service manual - part 274

H01002

AB0118

W02042

H02144
H10600

H10605

D Squib

Spiral
Cable

Airbag

Sensor

Assembly

D+

D–

ON

DTC B0102/11

DLC3

→ ←

Tc

CG

DI–328

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

3

Check airbag sensor assembly.

PREPARATION:
(a)

Connect the connector to the airbag sensor assembly.

(b)

Using a service wire, connect D+ and D– of the connector
(on the spiral cable side) between the spiral cable and the
steering wheel pad.

(c)

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

CHECK:
(a)

Turn the ignition switch to ON, and wait at least for 20 se-
conds.

(b)

Clear the DTC stored in memory (See step 5 on page 
DI–305).

(c)

Turn the ignition switch to LOCK, and wait at least for 20
seconds.

(d)

Turn the ignition switch to ON, and wait at least for 20 se-
conds.

(e)

Check the DTC (See page DI–305).

OK:

DTC B0102/11 is not output.

HINT:
Codes other than code B0102/11 may be output at this time, but
they are not relevant to this check.

NG

Replace airbag sensor assembly.

OK

H01003

H10600

AB0119

W02042

H10606

D Squib

Spiral
Cable

Airbag

Sensor

Assembly

ON

DTC B0102/11

DLC3

→

 ←

Tc

CG

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–329

LEXUS RX300   (RM785E)

4

Check D squib.

PREPARATION:
(a)

Turn the ignition switch to LOCK.

(b)

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

(c)

Connect the steering wheel pad connector.

(d)

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

CHECK:
(a)

Turn the ignition switch to ON, and wait at least for 20 se-
conds.

(b)

Clear the DTC stored in memory (See step 5 on page 
DI–305).

(c)

Turn the ignition switch to LOCK, and wait at least for 20
seconds.

(d)

Turn the ignition switch to ON, and wait at least for 20 se-
conds.

(e)

Check the DTC (See page DI–305).

OK:

DTC B0102/11 is not output.

HINT:
Codes other than code B0102/11 may be output at this time, but
they are not relevant to this check.

NG 

Replace steering wheel pad.

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. If the malfunctioning part can not be
detected by the simulation method, replace all SRS components including the wire harness.

H01000
H02145

H02200

D Squib

Spiral 
Cable

Airbag 

Sensor 

Assembly

D+

← →

(–)

(+)

H01004
H02145

H10607

D Squib

Spiral
Cable

(–)

(+)

Airbag
Sensor
Assembly

D+

DI–330

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

5

Check spiral cable.

PREPARATION:
Disconnect the connector between the airbag sensor assembly
and the spiral cable.
CHECK:
For the connector (on the spiral cable side) between the steer-
ing wheel pad and the spiral cable, measure the resistance be-
tween D+ and body ground.
OK:

Resistance: 1 MΩ or Higher

NG

Repair or replace spiral cable.

OK

6

Check harness between airbag sensor assembly and spiral cable.

CHECK:
For the connector (on the spiral cable side) between the spiral
cable and the airbag sensor assembly, measure the resistance
between D+ and body ground.
OK:

Resistance: 1 MΩ or Higher

NG

Repair or replace harness between airbag sen-
sor assembly and spiral cable.

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. If the malfunctioning part can not be
detected by the simulation method, replace all SRS components including the wire harness.

H01001
H02146

AB0119

H11570

D Squib

Spiral 
Cable

Airbag 

Sensor 

Assembly

D+

(–)

(+)

ON

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–331

LEXUS RX300   (RM785E)

DTC

B0103/12

Short in D Squib Circuit (to B+)

CIRCUIT DESCRIPTION

The D squib circuit consists of the airbag sensor assembly, spiral cable and steering wheel pad. 
It causes the SRS to deploy when the SRS deployment conditions are satisfied. 
For details of the function of each component, see OPERATION on page RS–2. 
DTC B0103/12 is recorded when a B+ short is detected in the D squib circuit.

DTC No.

DTC Detecting Condition

Trouble Area

B0103/12

S Short circuit in D squib wire harness (to B+)

S D squib malfunction

S Spiral cable malfunction

S Airbag sensor assembly malfunction

S Steering wheel pad (D squib)

S Spiral cable

S Airbag sensor assembly

S Wire harness

WIRING DIAGRAM

See page DI–318.

INSPECTION PROCEDURE

1

Prepare for inspection (See step 1 on page DI–431).

2

Check D squib circuit.

CHECK:
(a)

Turn ignition switch to ON.

(b)

For the connector (on the spiral cable side) between the
spiral cable and the steering wheel pad, measure the volt-
age between D+ and body ground.

OK:

Voltage: 0 V

NG

Go to step 5.

OK

DI6P6–06