Lexus NX: P Seat Airbag Active Mode Indicator (B1660)

DESCRIPTION

The passenger airbag ON/OFF indicator circuit consists of the airbag ECU assembly and passenger airbag ON/OFF indicator.

The passenger airbag ON/OFF indicator indicates the operation condition of the instrument panel passenger airbag assembly and front seat airbag assembly RH and LH.

DTC B1660 is stored when a malfunction is detected in the passenger airbag ON/OFF indicator circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
B1660	P Seat Airbag Active Mode Indicator	One of the following conditions is met: The airbag ECU assembly detects an open circuit signal, short circuit to ground signal or short circuit to B+ signal in the passenger airbag ON/OFF indicator circuit for 2 seconds. A passenger airbag ON/OFF indicator malfunction. An airbag ECU assembly malfunction.	Harness and connector Air conditioning control assembly Airbag ECU assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR CONDITION

(a) Turn the power switch on (IG).

(b) Check the passenger airbag ON/OFF indicator operation.

HINT:

Refer to the normal condition of the passenger airbag ON/OFF indicator.

Click here

ON/OFF Indicator Illumination	Proceed to
One or both indicators are always on	A
Both indicators are always off	B

B

GO TO STEP 7

A

2.	CHECK CONNECTION OF CONNECTORS

(a) Turn the power switch off.

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

(c) Check that the connectors are properly connected to the airbag ECU assembly and air conditioning control assembly.

The connectors are not properly connected

CONNECT CONNECTORS PROPERLY

The connectors are properly connected

3.	CHECK CONNECTORS

(a) Disconnect the connectors from the airbag ECU assembly and air conditioning control assembly.

(b) Check that the connectors (on the airbag ECU assembly side and air conditioning control assembly side) are not damaged.

*1 Air Conditioning Control Assembly *2 Airbag ECU Assembly

The connectors are deformed or damaged

REPLACE HARNESS AND CONNECTOR

The connectors are not deformed or damaged

4.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR

(a) Connect the connector to the air conditioning control assembly.

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

(c) Turn the power switch on (IG).

(d) Check the passenger airbag ON/OFF indicator operation.

The passenger airbag ON/OFF indicator comes on

GO TO STEP 6

The passenger airbag ON/OFF indicator does not come on

5.

CHECK DTC

(a) Connect the connectors to the airbag ECU assembly.

*1 Air Conditioning Control Assembly *2 Airbag ECU Assembly

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

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

(d) Clear the DTCs.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the power switch off.

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

(g) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

HINT:

Codes other than DTC B1660 may be output at this time, but they are not related to this check.

DTC B1660 is not output

USE SIMULATION METHOD TO CHECK

DTC B1660 is output

REPLACE AIRBAG ECU ASSEMBLY

6.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR CIRCUIT

(a) Disconnect the connector from the air conditioning control assembly.

*1	Air Conditioning Control Assembly	*2	Airbag ECU Assembly
*3	Connector C	*4	Connector B
*5	Service Wire	-	-
*a	Front view of wire harness connector (to Air Conditioning Control Assembly)	*b	Rear view of wire harness connector (to Airbag ECU Assembly)

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

(c) Turn the power switch on (IG).

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I13-12 (P-AB) - Body ground	Power switch on (IG)	Below 1 V
I13-13 (PAON) - Body ground	Power switch on (IG)	Below 1 V

(e) Turn the power switch off.

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

(g) Using a service wire, connect terminals 23 (PAON) and 17 (P-AB) of connector B.

NOTICE:

Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I13-12 (P-AB) - I13-13 (PAON)	Always	Below 1 Ω

(i) Disconnect the service wire from connector B.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I13-12 (P-AB) - I13-13 (PAON)	Always	1 MΩ or higher
I13-12 (P-AB) - Body ground	Always	1 MΩ or higher
I13-13 (PAON) - Body ground	Always	1 MΩ or higher

OK

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

NG

REPLACE HARNESS AND CONNECTOR

7.	CHECK CONNECTION OF CONNECTORS

(a) Turn the power switch off.

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

(c) Check that the connectors are properly connected to the airbag ECU assembly and air conditioning control assembly.

The connectors are not properly connected

CONNECT CONNECTORS PROPERLY

The connectors are properly connected

8.	CHECK CONNECTORS

(a) Disconnect the connectors from the airbag ECU assembly and air conditioning control assembly.

(b) Check that the connectors (on the airbag ECU assembly side and air conditioning control assembly side) are not damaged.

*1 Air Conditioning Control Assembly *2 Airbag ECU Assembly

The connectors are deformed or damaged

REPLACE HARNESS AND CONNECTOR

The connectors are not deformed or damaged

9.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR CIRCUIT

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

*1	Air Conditioning Control Assembly	*2	Airbag ECU Assembly
*3	Connector C	*4	Connector B
*5	Service Wire	-	-
*a	Front view of wire harness connector (to Air Conditioning Control Assembly)	*b	Rear view of wire harness connector (to Airbag ECU Assembly)

(b) Turn the power switch on (IG).

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I13-12 (P-AB) - Body ground	Power switch on (IG)	Below 1 V
I13-13 (PAON) - Body ground	Power switch on (IG)	Below 1 V

(d) Turn the power switch off.

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

(f) Using a service wire, connect terminals 23 (PAON) and 17 (P-AB) of connector B.

NOTICE:

Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I13-12 (P-AB) - I13-13 (PAON)	Always	Below 1 Ω

(h) Disconnect the service wire from connector B.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I13-12 (P-AB) - I13-13 (PAON)	Always	1 MΩ or higher
I13-12 (P-AB) - Body ground	Always	1 MΩ or higher
I13-13 (PAON) - Body ground	Always	1 MΩ or higher

NG

REPLACE HARNESS AND CONNECTOR

OK

10.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR (SOURCE VOLTAGE)

(a) Connect the connectors to the airbag ECU assembly.

*a Front view of wire harness connector (to Air Conditioning Control Assembly)

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

(c) Turn the power switch on (IG).

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I13-8 (IG+) - Body ground	Power switch on (IG)	11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

11.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR

(a) Turn the power switch off.

*a Rear view of wire harness connector (to Airbag ECU Assembly)

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

(c) Connect the connector to the air conditioning control assembly.

(d) Disconnect the connectors from the airbag ECU assembly.

(e) Using a service wire, connect terminal 23 (PAON) and body ground.

(f) Using a service wire, connect terminal 17 (P-AB) and body ground.

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

(h) Turn the power switch on (IG).

(i) Check the indicator according to the table below.

OK:

Tester Connection	Switch Condition	Passenger Airbag ON/OFF Indicator
I58-23 (PAON) - Body ground	Power switch on (IG)	"ON" comes on
I58-17 (P-AB) - Body ground	Power switch on (IG)	"OFF" comes on

(j) Disconnect the service wire from airbag ECU assembly.

NG

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

OK

12.

CHECK DTC

(a) Turn the power switch off.

*1 Air Conditioning Control Assembly *2 Airbag ECU Assembly

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

(c) Connect the connectors to the airbag ECU assembly.

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

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

(f) Clear the DTCs.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(g) Turn the power switch off.

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

(i) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

HINT:

Codes other than DTC B1660 may be output at this time, but they are not related to this check.

DTC B1660 is not output

USE SIMULATION METHOD TO CHECK

DTC B1660 is output

REPLACE AIRBAG ECU ASSEMBLY

READ NEXT: