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: RM000000YTT024X
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

DTC

B1860/64

Short in Driver Side Knee Airbag Squib Circuit

DTC

B1861/64

Open in Driver Side Knee Airbag Squib Circuit

DTC

B1862/64

Short to GND in Driver Side Knee Airbag Squib Circuit

DTC

B1863/64

Short to B+ in Driver Side Knee Airbag Squib Circuit

DESCRIPTION

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

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

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

DTC Code

DTC Detection Condition

Trouble Area

B1860/64

When one of the following conditions is met:

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

B1861/64

When one of the following conditions is met:

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

B1862/64

When one of the following conditions is met:

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

B1863/64

When one of the following conditions is met:

  • The airbag sensor center receives a short circuit to B+ signal in the knee airbag (Driver side squib) circuit for 0.5 seconds.
  • A driver side knee airbag squib malfunction.
  • A center airbag sensor malfunction.
  • Instrument panel wire
  • Driver side knee airbag assembly (Driver 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 DRIVER SIDE KNEE AIRBAG (DRIVER 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 driver 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 driver side knee airbag (driver 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 B1860, B1861, B1862 or B1863 is not output.

HINT:

Codes other than DTC B1860, B1861, B1862 and B1863 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 driver 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 (DRIVER SIDE KNEE AIRBAG 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

E24-1 (DK+) - Body ground

Engine switch on (IG)

Below 1 V

E24-2 (DK-) - 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

E24-1 (DK+) - E24-2 (DK-)

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

E24-1 (DK+) - E24-2 (DK-)

Always

1 MΩ or higher

E24-1 (DK+) - Body ground

Always

1 MΩ or higher

E24-2 (DK-) - Body ground

Always

1 MΩ or higher

OK

4.

CHECK CENTER AIRBAG SENSOR



(a) Connect the connectors to the driver 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 B1860, B1861, B1862 or B1863 is not output.

HINT:

Codes other than DTC B1860, B1861, B1862 and B1863 may be output at this time, but they are not related to this check.

OK