Supplemental Restraint System. Dtc B1660/43 Passenger Airbag Off Indicator Circuit Malfunction

The passenger airbag OFF indicator circuit consists of the center airbag sensor assembly and the multi-display.
The passenger airbag OFF indicator indicates the operation condition of the front passenger airbag assembly.
DTC B1660/43 is recorded when a malfunction is detected in the passenger airbag OFF indicator circuit.

DTC No.	DTC Detecting Condition	Trouble Area
B1660/43	The center airbag sensor assembly receives an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the passenger airbag OFF indicator circuit for 2 seconds. Passenger airbag OFF indicator malfunction Center airbag sensor assembly malfunction	Instrument panel wire Multi-display Center airbag sensor assembly

WIRING DIAGRAM

Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System.
Dtc
B1660/43 Passenger Airbag Off Indicator Circuit Malfunction

INSPECTION PROCEDURE

1.CHECK PASSENGER AIRBAG OFF INDICATOR

Turn the engine switch on (IG).

Check the passenger airbag OFF indicator operation.
HINT:
Refer to the normal condition of the passenger airbag OFF indicator (Click here).

Airbag cut off switch cylinder
Front passenger airbag assembly
Passenger airbag OFF indicator
ON position
Active
OFF
OFF position
Not active
ON
Result:
A:
Passenger airbag OFF indicator always comes on, when the airbag cut off switch cylinder is ON position.
B:
Passenger airbag OFF indicator does not come on, when the airbag cut off switch cylinder is OFF position.

Go to step 8

A

2.CHECK CONNECTION OF CONNECTORS

Turn the engine switch off.

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

Check that the connectors are properly connected to the center airbag sensor assembly and the multi-display.
OK:
The connectors are connected.

CONNECT CONNECTORS, THEN GO TO STEP 1

OK

3.CHECK MULTI-DISPLAY

Turn the engine switch off.

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

Disconnect the connector from the multi-display.

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

Turn the engine switch on (IG).

Check the passenger airbag OFF indicator operation.
OK:
The passenger airbag OFF indicator does not come on.

Go to step 7

NG

4.CHECK INSTRUMENT PANEL WIRE (OPEN)

Turn the engine switch off.

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

Disconnect the connectors from the center airbag sensor assembly.

Measure the resistance according to the value(s) in the table below.
Resistance:
Tester connection
Condition
Specified condition
L48-10 (AIR) -
L44-17 (P-AB)
Always
Below 1 Ω

REPAIR OR REPLACE INSTRUMENT PANEL WIRE

OK

5.CHECK INSTRUMENT PANEL WIRE (SHORT TO B+)

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

Turn the engine switch on (IG).

Measure the voltage according to the value(s) in the table below.
Voltage:
Tester connection
Condition
Specified condition
L48-10 (AIR) -
Body ground
Always
Below 1 V

REPAIR OR REPLACE INSTRUMENT PANEL WIRE

OK

6.CHECK INSTRUMENT PANEL WIRE (SHORT TO GROUND)

Turn the engine switch off.

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

Measure the resistance according to the value(s) in the table below.
Resistance:
Tester connection
Condition
Specified condition
L48-10 (AIR) -
Body ground
Always
1 MΩ or higher

REPAIR OR REPLACE INSTRUMENT PANEL WIRE

OK

7.CHECK CENTER AIRBAG SENSOR ASSEMBLY

Connect the connectors to the center airbag sensor assembly and the multi-display.

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

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

Clear the DTCs stored in memory (Click here).

Turn the engine switch off.

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

Check the DTCs (Click here).
OK:
DTC B1660/43 is not output.
HINT:
Codes other than DTC B1660/43 may be output at this time, but they are not related to this check.

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

USE SIMULATION METHOD TO CHECK

8.CHECK CONNECTION OF CONNECTORS

Turn the engine switch off.

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

Check that the connectors are properly connected to the center airbag sensor assembly and the multi-display.
OK:
The connectors are connected.

CONNECT CONNECTORS, THEN GO TO STEP 1

OK

9.CHECK INSTRUMENT PANEL WIRE (OPEN)

Turn the engine switch off.

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

Disconnect the connectors from the center airbag sensor assembly.

Measure the resistance according to the value(s) in the table below.
Resistance:
Tester connection
Condition
Specified condition
L48-10 (AIR) -
L44-17 (P-AB)
Always
Below 1 Ω

REPAIR OR REPLACE INSTRUMENT PANEL WIRE

OK

10.CHECK INSTRUMENT PANEL WIRE (SHORT TO B+)

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

Turn the engine switch on (IG).

Measure the voltage according to the value(s) in the table below.
Voltage:
Tester connection
Condition
Specified condition
L48-10 (AIR) -
Body ground
Always
Below 1 V

REPAIR OR REPLACE INSTRUMENT PANEL WIRE

OK

11.CHECK INSTRUMENT PANEL WIRE (SHORT TO GROUND)

Turn the engine switch off.

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

Measure the resistance according to the value(s) in the table below.
Resistance:
Tester connection
Condition
Specified condition
L48-10 (AIR) -
Body ground
Always
1 MΩ or higher

REPAIR OR REPLACE INSTRUMENT PANEL WIRE

OK

12.CHECK MULTI-DISPLAY (SOURCE VOLTAGE)

Connect the connectors to the center airbag sensor assembly.

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

Turn the engine switch on (IG).

Measure the voltage according to the value(s) in the table below.
Voltage:
Tester connection
Condition
Specified condition
L46-1 (+B1) -
Body ground
Always
10 to 14 V
L46-2 (ACC) -
Body ground
Engine switch on (ACC)
10 to 14 V
L46-3 (IG) -
Body ground
Engine switch on (IG)
10 to 14 V

REPAIR OR REPLACE WIRE HARNESS (MULTI-DISPLAY - BATTERY) OR BATTERY

OK

13.CHECK PASSENGER AIRBAG OFF INDICATOR

Turn the engine switch off.

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

Connect the connector to the multi-display.

Disconnect the connectors from the center airbag sensor assembly.

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

Turn the engine switch on (IG).

Check the indicator according to the conditions in the table below.
Result:
Tester connection
Condition
Passenger airbag OFF indicator
L48-10 (AIR) -
Body ground
Engine switch on (IG)
Indicator comes on

REPLACE MULTI-DISPLAY

OK

14.CHECK CENTER AIRBAG SENSOR ASSEMBLY

Turn the engine switch off.

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

Connect the connectors to the center airbag sensor assembly.

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

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

Clear the DTCs stored in memory (Click here).

Turn the engine switch off.

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

Check the DTCs (Click here).
OK:
DTC B1660/43 is not output.
HINT:
Codes other than DTC B1660/43 may be output at this time, but they are not related to this check.

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

USE SIMULATION METHOD TO CHECK

Airbag cut off switch cylinder	Front passenger airbag assembly	Passenger airbag OFF indicator
ON position	Active	OFF
OFF position	Not active	ON

Tester connection	Condition	Specified condition
L48-10 (AIR) - L44-17 (P-AB)	Always	Below 1 Ω