Home Vehicle Interior Supplemental Restraint Systems AIRBAG SYSTEM
Last Modified: 11-27-2007 1.6 C
Service Category: Vehicle Interior Section: Supplemental Restraint Systems
Model Year: 2008 Model: LX570 Doc ID: RM000002NL700AX
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

DTC

B1920/77

Short in Rear Pretensioner Squib RH Circuit

DTC

B1921/77

Open in Rear Pretensioner Squib RH Circuit

DTC

B1922/77

Short to GND in Rear Pretensioner Squib RH Circuit

DTC

B1923/77

Short to B+ in Rear Pretensioner Squib RH Circuit

DESCRIPTION

The rear pretensioner squib RH circuit consists of the center airbag sensor and the rear seat outer belt RH.

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

These DTCs are stored when a malfunction is detected in the rear pretensioner squib RH circuit.

DTC Code

DTC Detection Condition

Trouble Area

B1920/77

When one of the following conditions is met:

  • The center airbag sensor receives a line short circuit signal 5 times in the rear pretensioner squib RH circuit during the primary check.
  • A rear pretensioner squib RH malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Rear seat outer belt assembly RH (Rear pretensioner squib RH)
  • Center airbag sensor assembly

B1921/77

When one of the following conditions is met:

  • The center airbag sensor receives an open circuit signal in the rear pretensioner squib RH circuit for 2 seconds.
  • A rear pretensioner squib RH malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Rear seat outer belt assembly RH (Rear pretensioner squib RH)
  • Center airbag sensor assembly

B1922/77

When one of the following conditions is met:

  • The center airbag sensor receives a short circuit to ground signal in the rear pretensioner squib RH circuit for 0.5 seconds.
  • A rear pretensioner squib RH malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Rear seat outer belt assembly RH (Rear pretensioner squib RH)
  • Center airbag sensor assembly

B1923/77

When one of the following conditions is met:

  • The center airbag sensor receives a short circuit to B+ signal in the rear pretensioner squib RH circuit for 0.5 seconds.
  • A rear pretensioner squib RH malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Rear seat outer belt assembly RH (Rear pretensioner squib RH)
  • Center airbag sensor assembly

WIRING DIAGRAM



INSPECTION PROCEDURE

HINT:

To perform the simulation method, enter the "check mode (signal check) with the Techstream SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: CHECK MODE PROCEDURE (2008 LX570) , and then wiggle each connector of the airbag system or drive the vehicle on various type of road SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DIAGNOSIS SYSTEM (2008 LX570) .

PROCEDURE

1.

CHECK REAR SEAT OUTER BELT RH (REAR PRETENSIONER SQUIB RH)



(a) Turn the engine switch off.

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

(c) Disconnect the connectors from the rear seat outer belt RH.

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

CAUTION:

Never connect the tester to the rear seat outer belt RH (rear pretensioner squib RH) 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 stored in the memory SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

(h) Turn the engine switch off.

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

(j) Check for DTCs SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

OK:

DTC B1920, B1921, B1922 or B1923 is not output.

HINT:

Codes other than DTC B1920, B1921, B1922 and B1923 may be output at this time, but they are not related to this check.

OK

2.

CHECK CONNECTORS

(a) Turn the engine switch off.

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

(c) Disconnect SST from connector C.

(d) Check that the No. 2 floor wire connector (on the rear seat outer belt RH side) is not damaged.

OK:

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

OK

3.

CHECK NO. 2 FLOOR WIRE (REAR PRETENSIONER SQUIB RH CIRCUIT)



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

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

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

L14-1 (RR+) - Body ground

Engine switch on (IG)

Below 1 V

L14-2 (RR-) - 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

L14-1 (RR+) - L14-2 (RR-)

Always

Below 1 Ω

(g) Release the activation prevention mechanism built into connector B SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DIAGNOSIS SYSTEM (2008 LX570) .

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

L14-1 (RR+) - L14-2 (RR-)

Always

1 MΩ or higher

L14-1 (RR+) - Body ground

Always

1 MΩ or higher

L14-2 (RR-) - Body ground

Always

1 MΩ or higher

OK

4.

CHECK CENTER AIRBAG SENSOR



(a) Connect the connectors to the rear seat outer belt RH and the center airbag sensor.

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

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

(d) Clear the DTCs stored in the memory SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

(e) Turn the engine switch off.

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

(g) Check for DTCs SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

OK:

DTC B1920, B1921, B1922 or B1923 is not output.

HINT:

Codes other than DTC B1920, B1921, B1922 and B1923 may be output at this time, but they are not related to this check.

OK