Lexus RX300 (MCU15). Service manual - part 278

AB0119

H01024

H01075

H10600

H10616

→ ←

ON

DTC B0107/51

DLC3

Airbag
Sensor
Assembly

P Squib

Tc

CG

DI–344

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

4

Check P 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 front passenger airbag assembly 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 B0107/51 is not output.

HINT:
Codes other than code B0107/51 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. If the malfunctioning part can not be
detected by the simulation method, replace all SRS components including the wire harness.

H01022

H02146

AB0119

H04524

P Squib

Airbag 
Sensor 
Assembly

(–)

(+)

P+

ON

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–345

LEXUS RX300   (RM785E)

DTC

B0108/52

Short in P Squib Circuit (to B+)

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 B0108/52 is recorded when a B+ short is detected in the P squib circuit.

DTC No.

DTC Detecting Condition

Trouble Area

B0108/52

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

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

See page DI–335.

INSPECTION PROCEDURE

1

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

2

Check P squib circuit.

CHECK:
(a)

Turn the ignition switch to ON.

(b)

For the connector (on the front passenger airbag assem-
bly side) between the front passenger airbag assembly
and the airbag sensor assembly, measure the voltage be-
tween the P+ and body ground.

OK:

Voltage: 0 V

NG

Repair or replace harness or connector be-
tween front passenger airbag assembly and air-
bag sensor assembly.

OK

DI6PA–01

AB0118

H01023

H01076

H02144
H10600

H10617

P Squib

Airbag
Sensor
Assembly

P+

P–

DTC B0108/52

DLC3

ON

→

 ←

Tc

CG

DI–346

–

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 P+ and P– of the connector
(on the front passenger airbag assembly side) between
the front passenger airbag assembly and the airbag sen-
sor assembly.

(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 B0108/52 is not output.

HINT:
Codes other than code B0108/52 may be output at this time, but
they are not relevant to this check.

NG

Replace airbag sensor assembly.

OK

AB0119

H01024

H01076

H10600

H10618

→ ←

ON

DTC B0108/52

DLC3

Airbag
Sensor
Assembly

P Squib

Tc

CG

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–347

LEXUS RX300   (RM785E)

4

Check P 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 front passenger airbag assembly 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 B0108/52 is not output.

HINT:
Codes other than code B0108/52 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. If the malfunctioning part can not be
detected by the simulation method, replace all SRS components including the wire harness.