Lexus NX: Side Satellite Sensor Bus Lost Communication (RH) (B1642,B1643,B1647,B1648)

Lexus NX Service Manual / Vehicle Interior / Supplemental Restraint Systems / Airbag System / Side Satellite Sensor Bus Lost Communication (RH) (B1642,B1643,B1647,B1648)

DESCRIPTION

The circuit for the side collision sensor LH or RH is composed of the airbag ECU assembly, side airbag sensor assembly LH or RH and door side airbag sensor LH or RH.

The door side airbag sensor LH or RH and side airbag sensor assembly LH or RH detect impacts to the vehicle and send signals to the airbag ECU assembly to determine if the airbag should be deployed.

DTC B1642, B1643, B1647 or B1648 is stored when a malfunction is detected in the circuit for the side satellite sensor bus LH or RH.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
B1642	Side Satellite Sensor Bus Lost Communication (RH)	One of the following conditions is met: The airbag ECU assembly detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the circuit for the side satellite sensor bus RH for 2 seconds. A door side airbag sensor RH malfunction. A side airbag sensor assembly RH malfunction. An airbag ECU assembly malfunction.	Floor wire Front door wire RH Door side airbag sensor RH Side airbag sensor assembly RH Airbag ECU assembly
B1643	Side Satellite Sensor Bus Initialization Error (RH)	One of the following conditions is met: The airbag ECU assembly detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the circuit for the side satellite sensor bus RH for 2 seconds. A door side airbag sensor RH malfunction. A side airbag sensor assembly malfunction. An airbag ECU assembly malfunction.	Floor wire Front door wire RH Door side airbag sensor RH Side airbag sensor assembly RH Airbag ECU assembly
B1647	Side Satellite Sensor Bus Lost Communication (LH)	One of the following conditions is met: The airbag ECU assembly detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the circuit for the side satellite sensor bus LH for 2 seconds. A door side airbag sensor LH malfunction. A side airbag sensor assembly LH malfunction. An airbag ECU assembly malfunction.	No. 2 floor wire Front door wire LH Door side airbag sensor LH Side airbag sensor assembly LH Airbag ECU assembly
B1648	Side Satellite Sensor Bus Initialization Error (LH)	One of the following conditions is met: The airbag ECU assembly detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the circuit for the side satellite sensor bus LH for 2 seconds. A door side airbag sensor LH malfunction. A side airbag sensor assembly LH malfunction. An airbag ECU assembly malfunction.	No. 2 floor wire Front door wire LH Door side airbag sensor LH Side airbag sensor assembly LH Airbag ECU assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After the power switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
Click here
When disconnecting and reconnecting the auxiliary battery
Click here

HINT:

When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

Click here
After replacing the airbag ECU assembly, refer to initialization.
Click here

PROCEDURE

CHECK DTC

(a) Turn the power switch off.

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

Click here

Body Electrical > SRS Airbag > Trouble Codes

HINT:

Codes other than DTC B1642, B1643, B1647 and B1648 may be output at this time, but they are not related to this check.

DTC B1647 or B1648 is output

GO TO STEP 11

DTC B1642, B1643, B1647 and B1648 are not output

USE SIMULATION METHOD TO CHECK

DTC B1642 or B1643 is output

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.

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 side airbag sensor assembly RH.

(b) Check that the connectors (on the airbag ECU assembly side and side airbag sensor assembly RH side) are not damaged.

*1	Side Airbag Sensor Assembly RH
*2	Airbag ECU Assembly
*3	Floor Wire

The connectors are deformed or damaged

REPLACE FLOOR WIRE

The connectors are not deformed or damaged

4.	CHECK FLOOR WIRE

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

*1	Side Airbag Sensor Assembly RH	*2	Airbag ECU Assembly
*3	Floor Wire	*4	Connector C
*5	Connector B	*6	Service Wire
*a	Front view of wire harness connector (to Side Airbag Sensor Assembly RH)	*b	Rear view of wire harness connector (to Airbag ECU Assembly)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
P7-4 (BCR+) - Body ground	Power switch on (IG)	Below 1 V
P7-3 (BCR-) - 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 24 (BBR+) and 23 (BBR-) 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
P7-4 (BCR+) - P7-3 (BCR-)	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
P7-4 (BCR+) - P7-3 (BCR-)	Always	1 MΩ or higher
P7-4 (BCR+) - Body ground	Always	1 MΩ or higher
P7-3 (BCR-) - Body ground	Always	1 MΩ or higher

REPLACE FLOOR WIRE

5.	CHECK CONNECTION OF CONNECTOR

(a) Check that the connector is properly connected to the door side airbag sensor RH.

The connector is not properly connected

CONNECT CONNECTOR PROPERLY

The connector is properly connected

6.	CHECK CONNECTOR

(a) Disconnect the connector from the door side airbag sensor RH.

(b) Check that the connector (on the door side airbag sensor RH side) is not damaged.

*1	Door Side Airbag Sensor RH
*2	Side Airbag Sensor Assembly RH
*3	Front Door Wire RH
*4	Floor Wire

The connector is deformed or damaged

REPLACE FRONT DOOR WIRE RH

The connector is not deformed or damaged

7.	CHECK DOOR SIDE AIRBAG SENSOR RH CIRCUIT

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

*1	Door Side Airbag Sensor RH	*2	Side Airbag Sensor Assembly RH
*3	Connector E	*4	Connector B
*5	Service Wire	*6	Front Door Wire RH
*7	Floor Wire	-	-
*a	Rear view of wire harness connector (to Door Side Airbag Sensor RH)	*b	Front view of wire harness connector (to Side Airbag Sensor Assembly RH)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
P7-1 (BDR+) - Body ground	Power switch on (IG)	Below 1 V
P7-2 (BDR-) - 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 2 (BDR+) and 1 (BDR-) of connector E.

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
P7-1 (BDR+) - P7-2 (BDR-)	Always	Below 1 Ω

(h) Disconnect the service wire from connector E.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
P7-1 (BDR+) - P7-2 (BDR-)	Always	1 MΩ or higher
P7-1 (BDR+) - Body ground	Always	1 MΩ or higher
P7-2 (BDR-) - Body ground	Always	1 MΩ or higher

GO TO STEP 10

8.	CHECK SIDE AIRBAG SENSOR ASSEMBLY RH

(a) Connect the connectors to the airbag ECU assembly and door side airbag sensor RH.

*1	Side Airbag Sensor Assembly LH
*2	Airbag ECU Assembly

(b) Interchange the side airbag sensor assembly RH with LH and connect the connectors to them.

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

(e) Clear the DTCs stored in memory.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(f) Turn the power switch off.

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

(h) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

HINT:

Codes other than DTC B1642, B1643, B1647 and B1648 may be output at this time, but they are not related to this check.

(i) Turn the power switch off.

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

(k) Return the side airbag sensor assembly LH and RH to their original positions and connect the connectors to them.

DTC B1647 or B1648 is output

REPLACE SIDE AIRBAG SENSOR ASSEMBLY RH

DTC B1642, B1643, B1647 and B1648 are not output

USE SIMULATION METHOD TO CHECK

DTC B1642 or B1643 is output

9.	CHECK DOOR SIDE AIRBAG SENSOR RH

(a) Interchange the door side airbag sensor RH with LH and connect the connectors to them.

*1	Door Side Airbag Sensor LH
*2	Side Airbag Sensor Assembly RH

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

(d) Clear the DTCs stored in memory.

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 B1642, B1643, B1647 and B1648 may be output at this time, but they are not related to this check.

(h) Turn the power switch off.

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

(j) Return the door side airbag sensor LH and RH to their original positions and connect the connectors to them.

DTC B1647 or B1648 is output

REPLACE DOOR SIDE AIRBAG SENSOR RH

DTC B1642 or B1643 is output

REPLACE AIRBAG ECU ASSEMBLY

DTC B1642, B1643, B1647 and B1648 are not output

USE SIMULATION METHOD TO CHECK

10.	CHECK FLOOR WIRE

(a) Disconnect the floor wire connector from the front door wire RH.

*1	Door Side Airbag Sensor RH	*2	Side Airbag Sensor Assembly RH
*3	Front Door Wire RH	*4	Floor Wire
*5	Connector C	*6	Connector B
*7	Service Wire	-	-
*a	Front view of wire harness connector (to Front Door Wire RH)	*b	Front view of wire harness connector (to Side Airbag Sensor Assembly RH)

(b) Connect the cable to the negative (-) auxiliary 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
P7-1 (BDR+) - Body ground	Power switch on (IG)	Below 1 V
P7-2 (BDR-) - 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 2 (BDR+) and 1 (BDR-) of connector C.

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
P7-1 (BDR+) - P7-2 (BDR-)	Always	Below 1 Ω

(i) Disconnect the service wire from connector C.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
P7-1 (BDR+) - P7-2 (BDR-)	Always	1 MΩ or higher
P7-1 (BDR+) - Body ground	Always	1 MΩ or higher
P7-2 (BDR-) - Body ground	Always	1 MΩ or higher

REPLACE FRONT DOOR WIRE RH

REPLACE FLOOR WIRE

11.	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.

The connectors are not properly connected

CONNECT CONNECTORS PROPERLY

The connectors are properly connected

12.	CHECK CONNECTORS

(a) Disconnect the connectors from the airbag ECU assembly and side airbag sensor assembly LH.

(b) Check that the connectors (on the airbag ECU assembly side and side airbag sensor assembly LH side) are not damaged.

*1	Side Airbag Sensor Assembly LH
*2	Airbag ECU Assembly
*3	No. 2 Floor Wire

The connectors are deformed or damaged

REPLACE NO. 2 FLOOR WIRE

The connectors are not deformed or damaged

13.	CHECK NO. 2 FLOOR WIRE

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

*1	Side Airbag Sensor Assembly LH	*2	Airbag ECU Assembly
*3	No. 2 Floor Wire	*4	Connector C
*5	Connector B	*6	Service Wire
*a	Front view of wire harness connector (to Side Airbag Sensor Assembly LH)	*b	Rear view of wire harness connector (to Airbag ECU Assembly)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
Q7-4 (BCL+) - Body ground	Power switch on (IG)	Below 1 V
Q7-3 (BCL-) - 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 17 (BBL+) and 18 (BBL-) 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
Q7-4 (BCL+) - Q7-3 (BCL-)	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
Q7-4 (BCL+) - Q7-3 (BCL-)	Always	1 MΩ or higher
Q7-4 (BCL+) - Body ground	Always	1 MΩ or higher
Q7-3 (BCL-) - Body ground	Always	1 MΩ or higher

REPLACE NO. 2 FLOOR WIRE

14.	CHECK CONNECTION OF CONNECTOR

(a) Check that the connector is properly connected to the door side airbag sensor LH.

The connector is not properly connected

CONNECT CONNECTOR PROPERLY

The connector is properly connected

15.	CHECK CONNECTOR

(a) Disconnect the connector from the door side airbag sensor LH.

(b) Check that the connector (on the door side airbag sensor LH side) is not damaged.

*1	Door Side Airbag Sensor LH
*2	Side Airbag Sensor Assembly LH
*3	Front Door Wire LH
*4	No. 2 Floor Wire

The connector is deformed or damaged

REPLACE FRONT DOOR WIRE LH

The connector is not deformed or damaged

16.	CHECK DOOR SIDE AIRBAG SENSOR LH CIRCUIT

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

*1	Door Side Airbag Sensor LH	*2	Side Airbag Sensor Assembly LH
*3	Connector E	*4	Connector B
*5	Service Wire	*6	Front Door Wire LH
*7	No. 2 Floor Wire	-	-
*a	Rear view of wire harness connector (to Door Side Airbag Sensor LH)	*b	Front view of wire harness connector (to Side Airbag Sensor Assembly LH)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
Q7-1 (BDL+) - Body ground	Power switch on (IG)	Below 1 V
Q7-2 (BDL-) - 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 2 (BDL+) and 1 (BDL-) of connector E.

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
Q7-1 (BDL+) - Q7-2 (BDL-)	Always	Below 1 Ω

(h) Disconnect the service wire from connector E.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Q7-1 (BDL+) - Q7-2 (BDL-)	Always	1 MΩ or higher
Q7-1 (BDL+) - Body ground	Always	1 MΩ or higher
Q7-2 (BDL-) - Body ground	Always	1 MΩ or higher

GO TO STEP 19

17.	CHECK SIDE AIRBAG SENSOR ASSEMBLY LH

(a) Connect the connectors to the airbag ECU assembly and door side airbag sensor LH.

*1	Side Airbag Sensor Assembly RH
*2	Airbag ECU Assembly

(b) Interchange the side airbag sensor assembly LH with RH and connect the connectors to them.

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

(e) Clear the DTCs stored in memory.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(f) Turn the power switch off.

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

(h) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

HINT:

Codes other than DTC B1642, B1643, B1647 and B1648 may be output at this time, but they are not related to this check.

(i) Turn the power switch off.

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

(k) Return the side airbag sensor assembly RH and LH to their original positions and connect the connectors to them.

DTC B1642 or B1643 is output

REPLACE SIDE AIRBAG SENSOR ASSEMBLY LH

DTC B1642, B1643, B1647 and B1648 are not output

USE SIMULATION METHOD TO CHECK

DTC B1647 or B1648 is output

18.	CHECK DOOR SIDE AIRBAG SENSOR LH

(a) Interchange the door side airbag sensor LH with RH and connect the connectors to them.

*1	Door Side Airbag Sensor RH
*2	Side Airbag Sensor Assembly LH

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

(d) Clear the DTCs stored in memory.

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 B1642, B1643, B1647 and B1648 may be output at this time, but they are not related to this check.

(h) Turn the power switch off.

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

(j) Return the door side airbag sensor RH and LH to their original positions and connect the connectors to them.

DTC B1642 or B1643 is output

REPLACE DOOR SIDE AIRBAG SENSOR LH

DTC B1647 or B1648 is output

REPLACE AIRBAG ECU ASSEMBLY

DTC B1642, B1643, B1647 and B1648 are not output

USE SIMULATION METHOD TO CHECK

19.	CHECK NO. 2 FLOOR WIRE

(a) Disconnect the No. 2 floor wire connector from the front door wire LH.

*1	Door Side Airbag Sensor LH	*2	Side Airbag Sensor Assembly LH
*3	Front Door Wire LH	*4	No. 2 Floor Wire
*5	Connector C	*6	Connector B
*7	Service Wire	-	-
*a	Front view of wire harness connector (to Front Door Wire LH)	*b	Front view of wire harness connector (to Side Airbag Sensor Assembly LH)

(b) Connect the cable to the negative (-) auxiliary 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
Q7-1 (BDL+) - Body ground	Power switch on (IG)	Below 1 V
Q7-2 (BDL-) - 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 1 (BDL+) and 2 (BDL-) of connector C.

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
Q7-1 (BDL+) - Q7-2 (BDL-)	Always	Below 1 Ω

(i) Disconnect the service wire from connector C.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Q7-1 (BDL+) - Q7-2 (BDL-)	Always	1 MΩ or higher
Q7-1 (BDL+) - Body ground	Always	1 MΩ or higher
Q7-2 (BDL-) - Body ground	Always	1 MΩ or higher

REPLACE FRONT DOOR WIRE LH

REPLACE NO. 2 FLOOR WIRE

SEE MORE:

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Lexus NX: Side Satellite Sensor Bus Lost Communication (RH) (B1642,B1643,B1647,B1648)

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