SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

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Last Modified: 11-27-2007		1.6 C
Service Category: Vehicle Interior	Section: Supplemental Restraint Systems
Model Year: 2008	Model: LX570	Doc ID: RM000000XFI040X
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

DTC

B1800/51

Short in Driver Side Squib Circuit

DTC

B1801/51

Open in Driver Side Squib Circuit

DTC

B1802/51

Short to GND in Driver Side Squib Circuit

DTC

B1803/51

Short to B+ in Driver Side Squib Circuit

DESCRIPTION

The driver side squib circuit consists of the center airbag sensor, the spiral cable, and the steering pad.

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

These DTCs are stored when a malfunction is detected in the driver side squib circuit.

DTC Code	DTC Detection Condition	Trouble Area
B1800/51	When one of the following conditions is met: The center airbag sensor receives a line short circuit signal 5 times in the driver side squib circuit during the primary check. A driver side squib malfunction. A spiral cable malfunction. A center airbag sensor malfunction.	Instrument panel wire Spiral cable Steering pad (Driver side squib) Center airbag sensor assembly
B1801/51	When one of the following conditions is met: The center airbag sensor receives an open circuit signal in the driver side squib circuit for 2 seconds. A driver side squib malfunction. A spiral cable malfunction. A center airbag sensor malfunction.	Instrument panel wire Spiral cable Steering pad (Driver side squib) Center airbag sensor assembly
B1802/51	When one of the following conditions is met: The center airbag sensor receives a short circuit to ground signal in the driver side squib circuit for 0.5 seconds. A driver side squib malfunction. A spiral cable malfunction. A center airbag sensor malfunction.	Instrument panel wire Spiral cable Steering pad (Driver side squib) Center airbag sensor assembly
B1803/51	When one of the following conditions is met: The center airbag sensor receives a short circuit to B+ signal in the driver side squib circuit for 0.5 seconds. A driver side squib malfunction. A spiral cable malfunction. A center airbag sensor malfunction.	Instrument panel wire Spiral cable Steering pad (Driver side squib) Center airbag sensor assembly

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

When installing the spiral cable and steering wheel, be sure to adjust the spiral cable as it may break if the steering wheel is turned before adjusting the spiral cable .
w/ Navigation system:
After the engine switch is turned off, the HDD navigation system requires approximately 6 minutes to record various types of memory and settings. As a result, after turning the engine switch off, wait 6 minutes or more before disconnecting the cable from the negative (-) battery terminal.
When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected .

HINT:

To perform the simulation method, enter the "check mode (signal check) with the Techstream , and then wiggle each connector of the airbag system or drive the vehicle on various type of road .

PROCEDURE

1.	CHECK STEERING PAD (DRIVER SIDE SQUIB)

(a) Turn the engine switch off.

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

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

CAUTION:

Never connect the tester to the steering pad (driver side squib) for measurement, as this may lead to a serious injury due to airbag deployment.

NOTICE:

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

SST: 09843-18061

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

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

(g) Clear the DTCs .

(h) Turn the engine switch off.

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

(j) Check for DTCs .

OK:

DTC B1800, B1801, B1802 or B1803 is not output.

HINT:

Codes other than DTC B1800, B1801, B1802 and B1803 may be output at this time, but they are not related to this check.

2.	CHECK CONNECTOR

(a) Turn the engine switch off.

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

(d) Check that the spiral cable connectors (on the steering pad side) are not damaged.

OK:

The lock button is not disengaged, and the claw of the lock is not deformed or damaged.

3.	CHECK DRIVER SIDE SQUIB CIRCUIT

(a) Disconnect the connectors from the center airbag sensor.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
z48-2 (D+) - Body ground	Engine switch on (IG)	Below 1 V
z48-1 (D-) - Body ground	Engine switch on (IG)	Below 1 V

(d) Turn the engine switch off.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z48-2 (D+) - z48-1 (D-)	Always	Below 1 Ω

(g) Release the activation prevention mechanism built into connector B .

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z48-2 (D+) - z48-1 (D-)	Always	1 MΩ or higher
z48-2 (D+) - Body ground	Always	1 MΩ or higher
z48-1 (D-) - Body ground	Always	1 MΩ or higher

4.	CHECK CENTER AIRBAG SENSOR

(a) Connect the connectors to the steering pad and the center airbag sensor.

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

(d) Clear the DTCs .

(e) Turn the engine switch off.

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

(g) Check for DTCs .

OK:

DTC B1800, B1801, B1802 or B1803 is not output.

HINT:

Codes other than DTC B1800, B1801, B1802 and B1803 may be output at this time, but they are not related to this check.

5.	CHECK INSTRUMENT PANEL WIRE (CENTER AIRBAG SENSOR - SPIRAL CABLE)

(a) Restore the released activation prevention mechanism of connector B to its original condition.

(b) Disconnect the instrument panel wire connector from the spiral cable.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
E13-1 (D+) - Body ground	Engine switch on (IG)	Below 1 V
E13-2 (D-) - Body ground	Engine switch on (IG)	Below 1 V

(e) Turn the engine switch off.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
E13-1 (D+) - E13-2 (D-)	Always	Below 1 Ω

(h) Release the activation prevention mechanism built into connector B .

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
E13-1 (D+) - E13-2 (D-)	Always	1 MΩ or higher
E13-1 (D+) - Body ground	Always	1 MΩ or higher
E13-2 (D-) - Body ground	Always	1 MΩ or higher