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: RM000002O2S00IX
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

DTC

B1825/56

Short in Side Squib LH Circuit

DTC

B1826/56

Open in Side Squib LH Circuit

DTC

B1827/56

Short to GND in Side Squib LH Circuit

DTC

B1828/56

Short to B+ in Side Squib LH Circuit

DESCRIPTION

The side squib LH circuit consists of the center airbag sensor and the front seat side airbag LH.

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

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

DTC Code	DTC Detection Condition	Trouble Area
B1825/56	When one of the following conditions is met: The center airbag sensor receives a line short circuit signal 5 times in the side squib LH circuit during the primary check. A side squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat side airbag assembly LH (Side squib LH) Center airbag sensor assembly
B1826/56	When one of the following conditions is met: The center airbag sensor receives an open circuit signal in the side squib LH circuit for 2 seconds. A side squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat side airbag assembly LH (Side squib LH) Center airbag sensor assembly
B1827/56	When one of the following conditions is met: The center airbag sensor receives a short circuit to ground signal in the side squib LH circuit for 0.5 seconds. A side squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat side airbag assembly LH (Side squib LH) Center airbag sensor assembly
B1828/56	When one of the following conditions is met: The center airbag sensor receives a short circuit to B+ signal in the side squib LH circuit for 0.5 seconds. A side squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat side airbag assembly LH (Side squib LH) Center airbag sensor assembly

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

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 FRONT SEAT SIDE AIRBAG LH (SIDE SQUIB LH)

(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 red wire side of SST (resistance: 2.1 Ω) to connector C.

CAUTION:

Never connect the tester to the front seat side airbag LH (side squib LH) 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 B1825, B1826, B1827 or B1828 is not output.

HINT:

Codes other than DTC B1825, B1826, B1827 and B1828 may be output at this time, but they are not related to this check.

2.	CHECK FLOOR WIRE (SIDE SQUIB LH CIRCUIT)

(a) Turn the engine switch off.

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

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

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

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
K5-1 (SFL+) - Body ground	Engine switch on (IG)	Below 1 V
K5-2 (SFL-) - Body ground	Engine switch on (IG)	Below 1 V

(g) Turn the engine switch off.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
K5-1 (SFL+) - K5-2 (SFL-)	Always	Below 1 Ω

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
K5-1 (SFL+) - K5-2 (SFL-)	Always	1 MΩ or higher
K5-1 (SFL+) - Body ground	Always	1 MΩ or higher
K5-2 (SFL-) - Body ground	Always	1 MΩ or higher

3.	CHECK CENTER AIRBAG SENSOR

(a) Connect the connectors to the front seat side airbag LH 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 B1825, B1826, B1827 or B1828 is not output.

HINT:

Codes other than DTC B1825, B1826, B1827 and B1828 may be output at this time, but they are not related to this check.