Lexus IS250 IS220d GSE20 ALE20 - SUPPLEMENTAL RESTRAINT SYSTEM

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FRONT PASSENGER AIRBAG ASSEMBLY (FRONT PASSENGER SIDE SQUIB)

CHECK CONNECTOR

CHECK FRONT PASSENGER SIDE SQUIB CIRCUIT

CHECK CENTER AIRBAG SENSOR ASSEMBLY

CHECK INSTRUMENT PANEL WIRE

CHECK INSTRUMENT PANEL WIRE ASSEMBLY

DTC B1805/52 Short in Front Passenger Side Squib Circuit

DTC B1806/52 Open in Front Passenger Side Squib Circuit

DTC B1807/52 Short to GND in Front Passenger Side Squib Circuit

DTC B1808/52 Short to B+ in Front Passenger Side Squib Circuit

DESCRIPTION

The front passenger side squib circuit consists of the center airbag sensor assembly and the front passenger airbag assembly.

The circuit instructs the SRS to deploy when deployment conditions are met.

These DTCs are recorded when a malfunction is detected in the front passenger side squib circuit.

DTC No.	DTC Detection Condition	Trouble Area
B1805/52	The center airbag sensor assembly receives a line short circuit signal 5 times in the front passenger side squib circuit during primary check. Front passenger side squib malfunction Center airbag sensor assembly malfunction	Instrument panel wire Instrument panel wire assembly Front passenger airbag assembly (Front passenger side squib) Center airbag sensor assembly
B1806/52	The center airbag sensor assembly receives an open circuit signal in the front passenger side squib circuit for 2 seconds. Front passenger side squib malfunction Center airbag sensor assembly malfunction	Instrument panel wire Instrument panel wire assembly Front passenger airbag assembly (Front passenger side squib) Center airbag sensor assembly
B1807/52	The center airbag sensor assembly receives a short circuit to ground signal in the front passenger side squib circuit for 0.5 seconds. Front passenger side squib malfunction Center airbag sensor assembly malfunction	Instrument panel wire Instrument panel wire assembly Front passenger airbag assembly (Front passenger side squib) Center airbag sensor assembly
B1808/52	The center airbag sensor assembly receives a short circuit to B+ signal in the front passenger side squib circuit for 0.5 seconds. Front passenger side squib malfunction Center airbag sensor assembly malfunction	Instrument panel wire Instrument panel wire assembly Front passenger airbag assembly (Front passenger side squib) Center airbag sensor assembly

WIRING DIAGRAM

Dtc B1805/52 Short In Front Passenger Side Squib Circuit. SUPPLEMENTAL RESTRAINT SYSTEM. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

HINT:

Perform the simulation method by selecting the "check mode" (signal check) with the intelligent tester .

After selecting the "check mode" (signal check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on a city or rough road .

1.CHECK FRONT PASSENGER AIRBAG ASSEMBLY (FRONT PASSENGER SIDE SQUIB)

Dtc B1805/52 Short In Front Passenger Side Squib Circuit. SUPPLEMENTAL RESTRAINT SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Turn the engine switch off.

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

Disconnect the connectors from the front passenger airbag assembly.

Connect the white wire side of SST (resistance 2.1 Ω) to connector "E" (orange connector).

CAUTION:

Never connect a tester to the front passenger airbag assembly (front passenger side squib) for measurement, as this may lead to a serious injury due to airbag deployment.

NOTICE:

Do not forcibly insert the SST into the terminals of the connector when connecting.

Insert straight the SST into the terminals of the connector.

SST
09843-18060

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

Turn the engine switch on (IG), and wait for at least 60 seconds.

Clear the DTCs stored in the memory .

Turn the engine switch off.

Turn the engine switch on (IG), and wait for at least 60 seconds.

Check for DTCs .

OK:
DTC B1805, B1806, B1807, B1808 or 52 is not output.

HINT:

Codes other than DTC B1805, B1806, B1807, B1808 and 52 may be output at this time, but they are not related to this check.

Go to step 5

OK

4.CHECK CENTER AIRBAG SENSOR ASSEMBLY

Connect the connectors to the front passenger airbag assembly and the center airbag sensor assembly.

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

Turn the engine switch on (IG), and wait for at least 60 seconds.

Clear the DTCs stored in the memory .

Turn the engine switch off.

Turn the engine switch on (IG), and wait for at least 60 seconds.

Check for DTCs .

OK:
DTC B1805, B1806, B1807, B1808 or 52 is not output.

HINT:

Codes other than DTC B1805, B1806, B1807, B1808 and 52 may be output at this time, but they are not related to this check.

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

USE SIMULATION METHOD TO CHECK

5.CHECK INSTRUMENT PANEL WIRE

Restore the released activation prevention mechanism of connector "B" to the original condition.

Disconnect the instrument panel wire connector from the instrument panel wire assembly.

Check for a short to B+ in the circuit.

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

Turn the engine switch on (IG).

Measure the voltage according to the value(s) in the table below.

Standard voltage:
Tester connection Condition Specified condition
Ja1-1 (P+) - Body ground Engine switch on (IG) Below 1 V
Ja1-2 (P-) - Body ground Engine switch on (IG) Below 1 V

Check for an open in the circuit.

Turn the engine switch off.

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

Measure the resistance according to the value(s) in the table below.

Standard resistance:
Tester connection Condition Specified condition
Ja1-1 (P+) - Ja1-2 (P-) Always Below 1 Ω

Check for a short to ground in the circuit.

Measure the resistance according to the value(s) in the table below.

Standard resistance:
Tester connection Condition Specified condition
Ja1-1 (P+) - Body ground Always 1 MΩ or higher
Ja1-2 (P-) - Body ground Always 1 MΩ or higher

Check for a short in the circuit.

Release the activation prevention mechanism built into connector "B" .

Measure the resistance according to the value(s) in the table below.

Standard resistance:
Tester connection Condition Specified condition
Ja1-1 (P+) - Ja1-2 (P-) Always 1 MΩ or higher

REPAIR OR REPLACE INSTRUMENT PANEL WIRE

OK

6.CHECK INSTRUMENT PANEL WIRE ASSEMBLY

Check for a short to B+ in the circuit.

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

Turn the engine switch on (IG).

Measure the voltage according to the value(s) in the table below.

Standard voltage:
Tester connection Condition Specified condition
a1-2 (P+) - Body ground Engine switch on (IG) Below 1 V
a1-1 (P-) - Body ground Engine switch on (IG) Below 1 V

Check for an open in the circuit.

Turn the engine switch off.

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

Measure the resistance according to the value(s) in the table below.

Standard resistance:
Tester connection Condition Specified condition
a1-2 (P+) - a1-1 (P-) Always Below 1 Ω

Check for a short to ground in the circuit.

Measure the resistance according to the value(s) in the table below.

Standard resistance:
Tester connection Condition Specified condition
a1-2 (P+) - Body ground Always 1 MΩ or higher
a1-1 (P-) - Body ground Always 1 MΩ or higher

Check for a short in the circuit.

Release the activation prevention mechanism built into connector "D" .

Measure the resistance according to the value(s) in the table below.

Standard resistance:
Tester connection Condition Specified condition
a1-2 (P+) - a1-1 (P-) Always 1 MΩ or higher

REPAIR OR REPLACE INSTRUMENT PANEL WIRE ASSEMBLY

USE SIMULATION METHOD TO CHECK

Tester connection	Condition	Specified condition
Ja1-1 (P+) - Body ground	Engine switch on (IG)	Below 1 V
Ja1-2 (P-) - Body ground	Engine switch on (IG)	Below 1 V