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: RM000000ZRT01AX
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

DTC

B1865/65

Short in Front Passenger Side Knee Airbag Squib Circuit

DTC

B1866/65

Open in Front Passenger Side Knee Airbag Squib Circuit

DTC

B1867/65

Short to GND in Front Passenger Side Knee Airbag Squib Circuit

DTC

B1868/65

Short to B+ in Front Passenger Side Knee Airbag Squib Circuit

DESCRIPTION

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

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

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

DTC Code

DTC Detection Condition

Trouble Area

B1865/65

When one of the following conditions is met:

  • The center airbag sensor receives a line short circuit signal 5 times in the front passenger side knee airbag squib circuit during the primary check.
  • A front passenger side knee airbag squib malfunction.
  • A center airbag sensor malfunction.
  • Instrument panel wire
  • Front passenger side knee airbag assembly (Front passenger side knee squib)
  • Center airbag sensor assembly

B1866/65

When one of the following conditions is met:

  • The center airbag sensor receives an open circuit signal in the front passenger side knee airbag squib circuit for 2 seconds.
  • A front passenger side knee airbag squib malfunction.
  • A center airbag sensor malfunction.
  • Instrument panel wire
  • Front passenger side knee airbag assembly (Front passenger side knee squib)
  • Center airbag sensor assembly

B1867/65

When one of the following conditions is met:

  • The center airbag sensor receives a short circuit to ground signal in the front passenger side knee airbag squib circuit for 0.5 seconds.
  • A front passenger side knee airbag squib malfunction.
  • A center airbag sensor malfunction.
  • Instrument panel wire
  • Front passenger side knee airbag assembly (Front passenger side knee squib)
  • Center airbag sensor assembly

B1868/65

When one of the following conditions is met:

  • The center airbag sensor receives a short circuit to B+ signal in the front passenger side knee airbag squib circuit for 0.5 seconds.
  • A front passenger side knee airbag squib malfunction.
  • A center airbag sensor malfunction.
  • Instrument panel wire
  • Front passenger side knee airbag assembly (Front passenger side knee squib)
  • 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 FRONT PASSENGER SIDE KNEE AIRBAG (FRONT PASSENGER SIDE KNEE SQUIB)



(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 connector from the front passenger side knee airbag.

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

CAUTION:

Never connect the tester to the front passenger side knee airbag (front passenger side knee 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 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 B1865, B1866, B1867 or B1868 is not output.

HINT:

Codes other than DTC B1865, B1866, B1867 and B1868 may be output at this time, but they are not related to this check.

OK

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.

(c) Disconnect SST from connector C.

(d) Check that the instrument panel wire connector (on the front passenger side knee airbag 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 INSTRUMENT PANEL WIRE (FRONT PASSENGER KNEE 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.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

E40-1 (PK+) - Body ground

Engine switch on (IG)

Below 1 V

E40-2 (PK-) - 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

E40-1 (PK+) - E40-2 (PK-)

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

E40-1 (PK+) - E40-2 (PK-)

Always

1 MΩ or higher

E40-1 (PK+) - Body ground

Always

1 MΩ or higher

E40-2 (PK-) - Body ground

Always

1 MΩ or higher

OK

4.

CHECK CENTER AIRBAG SENSOR



(a) Connect the connectors to the front passenger side knee airbag and the center airbag sensor.

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

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

(d) Clear the DTCs 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 B1865, B1866, B1867 or B1868 is not output.

HINT:

Codes other than DTC B1865, B1866, B1867 and B1868 may be output at this time, but they are not related to this check.

OK