Lexus RX300 (MCU15). Service manual - part 289

H16270

H01016

H16635

P/T Squib (LH)

Airbag 
Sensor 
Assembly

PL–

PL+

(+)

(–)

DI–388

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

INSPECTION PROCEDURE

1

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

2

Check P/T squib (LH) circuit.

PREPARATION:
Release the airbag activation prevention mechanism of the
connector (on the airbag sensor assembly side) between the
airbag sensor assembly and the seat belt pretensioner (LH) 
(See page DI–305).
CHECK:
For the connector (on the seat belt pretensioner side) between
the seat belt pretensioner (LH) and the airbag sensor assembly,
measure the resistance between PL+ and PL–.
OK:

Resistance: 1 MΩ or Higher

NG

Repair or replace harness or connector be-
tween seat belt pretensioner (LH) and airbag
sensor assembly.

OK

H01017
AB0119

H01086

H10600

H10627

P/T Squib (LH)

Airbag
Sensor
Assembly

DTC B0135/73

ON

→

 ←

DLC3

Tc

CG

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–389

LEXUS RX300   (RM785E)

3

Check airbag sensor assembly.

PREPARATION:
(a)

Connect the connector to the airbag sensor assembly.

(b)

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 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 B0135/73 is not output.

HINT:
Codes other than code B0135/73 may be output at this time, but
they are not relevant to this check.

NG

Replace airbag sensor assembly.

OK

H01018
AB0119

H01086

H10600

H10628

→ ←

ON

Airbag
Sensor
Assembly

P/T  Squib (LH)

DTC B0135/73

DLC3

Tc

CG

DI–390

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

4

Check P/T squib (LH).

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 seat belt pretensioner (LH) connector.

(d)

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

CHECK:
(a)

Turn the ignition switch to LOOK, and wait at least for 20
second.

(b)

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

(c)

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

(d)

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

(e)

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

(f)

Check the DTC (See page DI–305).

OK:

DTC B0135/73 is not output.

HINT:
Codes other than code B0135/73 may be output at this time, but
they are not relevant to this check.

NG

Replace seat belt pretensioner (LH).

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.

H16270

H01016

H16635

P/T Squib (LH)

Airbag 
Sensor 
Assembly

PL+

PL–

(+)

(–)

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–391

LEXUS RX300   (RM785E)

DTC

B0136/74

Open in P/T Squib (LH) Circuit

CIRCUIT DESCRIPTION

The P/T squib circuit (LH) consists of the airbag sensor assembly and seat belt pretensioner (LH). 
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 B0136/74 is recorded when an open is detected in the P/T squib (LH) circuit.

DTC No.

DTC Detecting Condition

Trouble Area

B0136/74

S Open circuit in PL+ wire harness or PL– wire harness of

squib

S P/T squib (LH) malfunction

S Airbag sensor assembly malfunction

S Seat belt pretensioner (LH)

S Airbag sensor assembly

S Wire harness

WIRING DIAGRAM

See page DI–387.

INSPECTION PROCEDURE

1

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

2

Check P/T squib (LH) circuit.

CHECK:
For the connector (on the seat belt pretensioner side) between
the seat belt pretensioner (LH) and the airbag sensor assembly,
measure the resistance between PL+ and PL–.
OK:

Resistance: Below 1 Ω

NG

Repair or replace harness or connector be-
tween seat belt pretensioner (LH) and airbag
sensor assembly.

OK

DI6PO–06