Lexus RX300 (MCU15). Service manual - part 275

H01002

AB0119
W02043

H02144
H10600

H10608

D Squib

Spiral
Cable

Airbag

Sensor

Assembly

D+

D–

ON

DTC B0103/12

DLC3

→

 ←

Tc

CG

DI–332

–

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 B0103/12 is not output.

HINT:
Codes other than code B0103/12 may be output at this time, but
they are not relevant to this check.

NG

Replace airbag sensor assembly.

OK

AB0019

W02043

H01003

H10600

H10609

→ ←

Spiral
Cable

ON

DTC B0103/12

DLC3

Airbag

Sensor

Assembly

D Squib

Tc

CG

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–333

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 B0103/12 is not output.

HINT:
Codes other than code B0103/12 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
AB0119
H02146

H02202

D Squib

Spiral 
Cable

Airbag 

Sensor 

Assembly

D+

← →

(–)

(+)

ON

H01004
R14288

AB0119

H08261

D Squib

Spiral
Cable

(–)

(+)

D+

Airbag
Sensor
Assembly

ON

DI–334

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

5

Check spiral cable.

PREPARATION:
(a)

Turn the ignition switch to LOCK.

(b)

Disconnect the connector between the airbag sensor as-
sembly and the spiral cable.

CHECK:
(a)

Turn the 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

Repair or replace spiral cable.

OK

6

Check harness between airbag sensor assembly and spiral cable.

CHECK:
(a)

Turn the ignition switch to ON.

(b)

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

OK:

Voltage: 0 V

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.

H01454

P Squib

10

Airbag Sensor Assembly

2

Y–R

A28

Y–G

1

11

A28

P+

P–

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–335

LEXUS RX300   (RM785E)

DTC

B0105/53

Short in P Squib Circuit

CIRCUIT DESCRIPTION

The P squib circuit consists of the airbag sensor assembly and front passenger airbag assembly. 
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 B0105/53 is recorded when a short is detected in the P squib circuit.

DTC No.

DTC Detecting Condition

Trouble Area

B0105/53

S Short circuit in P squib wire harness

S P squib malfunction

S Airbag sensor assembly malfunction

S Front passenger airbag assembly (P squib)

S Airbag sensor assembly

S Wire harness

WIRING DIAGRAM

DI6P7–07