Lexus RX300 (MCU15). Service manual - part 297

H03355
H03356

H09518

Airbag 
Sensor 
Assembly

Front Airbag 
Sensor (RH)

(+)

+SR

(–)

–SR

Airbag Sensor 
Assembly

H03353

H03356

H03360

H16296

Front Airbag 
Sensor (RH)

Airbag 
Sensor 
Assembly

(+)

+SR

Airbag Sensor 
Assembly

(–)

–SR

+SR

–SR

DI–420

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

4

Check wire harness.

CHECK:
For the connector (on the airbag sensor assembly side) be-
tween the front airbag sensor (RH) and the airbag sensor as-
sembly, measure the resistance between +SR and –SR.
OK:

Resistance: 1 MΩ or Higher

NG

Go to step 10.

OK

5

Check wire harness.

PREPARATION:
Using a service wire, connect +SR and –SR of the connector
(on the front airbag sensor (RH) side) between the airbag sen-
sor assembly and the front airbag sensor (RH).
CHECK:
For the connector (on the airbag sensor assembly side) be-
tween the front airbag sensor (RH) and the airbag sensor as-
sembly, measure the resistance between +SR and –SR.
OK:

Resistance: Below 1 Ω

NG

Go to step 11.

OK

H04504

H01062

H08346

Airbag 
Sensor 
Assembly

Front Airbag 
Sensor (RH)

(+)

+SR

(–)

–SR

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–421

LEXUS RX300   (RM785E)

6

Check front airbag sensor (RH).

CHECK:
For the connector of the front airbag sensor (RH), measure the
resistance between +SR and –SR.
OK:

Resistance: 300 – 1500 Ω

NG

Replace front airbag sensor (RH).

OK

H02757
AB0119

H01063

H10600

H10638

Front Airbag
Sensor (RH)

Airbag
Sensor
Assembly

ON

DTC B1156/B1157/15

→ ←

→ ←

DLC3

Tc

CG

DI–422

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

LEXUS RX300   (RM785E)

7

Check airbag sensor assembly.

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 airbag sensor (RH) connector and air-
bag sensor 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 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 B1156/B1157/15 is not output.

HINT:
Codes other than code B1156/B1157/15 may be output at this
time, but they are not relevant to this check.

NG

Replace airbag sensor 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.

AB0119

H03354

H03364

H08348

Airbag 
Sensor 
Assembly

Front Airbag 
Sensor (RH)

(+)

+SR

(–)

–SR

ON

Engine Room No. 2
Wire Harness

← →

H03354
H03362

H08349

Airbag 
Sensor 
Assembly

Front Airbag 
Sensor (RH)

(+)

+SR

(–)

–SR

Engine Room No. 2
Wire Harness

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–423

LEXUS RX300   (RM785E)

8

Check engine room No. 2 wire harness (to B+).

PREPARATION:
Disconnect the engine room No. 2 wire harness connector on
the airbag sensor assembly side.
CHECK:
(a)

Turn the ignition switch to ON.

(b)

For the connector (on the RH front door wire harness
side) between the airbag sensor assembly and the en-
gine room No. 2 wire harness, measure the voltage be-
tween body ground and each of +SR and –SR.

OK:

Voltage: Below 1 V

NG

Repair or replace engine room No. 2 wire har-
ness.

OK

Repair or replace harness or connector between airbag sensor assembly and engine room No.
2 wire harness.

9

Check engine room No. 2 wire harness (to ground).

PREPARATION:
Disconnect the engine room No. 2 wire harness connector on
the airbag sensor assembly side.
CHECK:
For the connector (on the engine room No. 2 wire harness side)
between the airbag sensor assembly and the engine room No.
2 wire harness, measure the resistance between body ground
and each of +SR and –SR.
OK:

Resistance: 1 MΩ or Higher

NG

Repair or replace engine room No. 2 wire har-
ness.

OK

Repair or replace harness or connector between airbag sensor assembly and engine room No.
2 wire harness.