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: RM0000038B4003X
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

DTC

B1662/45

Indicator Light Circuit Malfunction

DESCRIPTION

The indicator light circuit consists of the center airbag sensor and the combination meter.

When the center airbag sensor detects a malfunction in the SRS airbag system, the SRS warning light comes on to inform the driver. It also comes on when the source voltage drops, and automatically goes off in approximately 10 seconds after the source voltage returns to normal (DTC is not stored).

The SRS warning light comes on for 6 seconds after the engine switch is turned on (IG) and goes off if the system is normal.

When an open circuit is detected, such as when the connector between the combination meter and the center airbag sensor is disconnected, the SRS warning light remains on even when approximately 6 seconds elapsed after the engine switch is turned on (IG).

DTC B1662/45 is stored when a malfunction is detected in the indicator light circuit.

DTC Code

DTC Detection Condition

Trouble Area

B1662/45

When one of the following conditions is met:

  • The center airbag sensor receives an open circuit signal, a short to ground signal or a short circuit to ground signal or a short circuit to B+ signal in the indicator light circuit for 2 seconds.
  • A combination meter malfunction.
  • A center airbag sensor malfunction.
  • Combination meter (SRS warning light)
  • Center airbag sensor assembly
  • Instrument panel wire

WIRING DIAGRAM



INSPECTION PROCEDURE

PROCEDURE

1.

CHECK CAN COMMUNICATION SYSTEM

(a) Check if a CAN communication DTC is output NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM (2008 LX570) .

Result

Result

Proceed to

DTC is not output

A

DTC is output

B

A

2.

CHECK BATTERY

(a) Measure the voltage of the battery.

Standard voltage:

11 to 14 V

OK

3.

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) Check that the connectors are properly connected to the center airbag sensor and combination meter.

OK:

The connectors are properly connected.

OK

4.

CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE OF CENTER AIRBAG SENSOR)



(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) Turn the engine switch on (IG).

(d) Operate all the components of the electrical system (defogger, wipers, headlights, heater blower, etc.).

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

E47-21 (IG2) - E47-25 (E1)

Engine switch on (IG)

11 to 14 V

E47-21 (IG2) - E47-26 (E2)

Engine switch on (IG)

11 to 14 V

OK

5.

CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE OF COMBINATION METER)



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

(b) Disconnect the E77 connector from the combination meter.

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

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

E77-30 (IG+) - E77-26 (ET)

Engine switch on (IG)

11 to 14 V

OK

6.

CHECK SRS WARNING LIGHT (SHORT TO GROUND)

(a) Turn the engine switch off.

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

(c) Connect the connector to the combination meter.

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

(e) Turn the engine switch on (IG).

(f) Check the SRS warning light condition.

OK:

After the primary check period, SRS warning light goes off for approximately 10 seconds and then remains on.

HINT:

The primary check period is approximately 6 seconds after the engine switch is turned on (IG).

OK