Toyota 4Runner: Lost Communication with Front Satellite Sensor Bus (B161A/8A)

Toyota 4Runner Service Manual / Vehicle Interior / Supplemental Restraint Systems / Airbag System / Lost Communication with Front Satellite Sensor Bus (B161A/8A)

DESCRIPTION

The front collision sensor circuit (front airbag sensor RH circuit and front airbag sensor LH circuit) is composed of the center airbag sensor assembly, front airbag sensor RH and front airbag sensor LH.

The front airbag sensor RH or front airbag sensor LH detects impacts to the vehicle and sends signals to the center airbag sensor assembly to determine if the airbag should be deployed.

DTC B161A/8A is stored when a malfunction is detected in the front collision sensor circuit (front airbag sensor RH circuit and front airbag sensor LH circuit).

DTC Code	DTC Detection Condition	Trouble Area
B161A/8A	One of the following conditions is met: The center airbag sensor assembly detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the front collision sensor circuit (front airbag sensor RH circuit and front airbag sensor LH circuit). A front airbag sensor RH malfunction. A front airbag sensor LH malfunction. A center airbag sensor assembly malfunction.	Instrument panel wire Engine room main wire Front airbag sensor RH Front airbag sensor LH Center airbag sensor assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected (See page ).

PROCEDURE

1.	CHECK FOR DTC

(a) Turn the ignition switch to ON, and wait for at least 60 seconds.

(b) Turn the ignition switch off.

HINT:

If a communication error occurs, DTCs for both the LH and RH sides will be stored simultaneously. To identify the malfunctioning area, turn the ignition switch off and then to ON again.

(d) Check for DTCs (See page ).

Result

Result	Proceed to
DTCs B1613 and B1618 are not output	A
DTC B1613 is output	B
DTC B1618 is output	C

HINT:

DTCs indicating communication errors will be changed to DTCs indicating errors in initialization by turning the ignition switch off and then to ON again.
Codes other than DTCs B1613 and B1618 may be output at this time, but they are not related to this check.

GO TO DTC B1613/83

GO TO DTC B1618/84

2.	CHECK CENTER AIRBAG SENSOR ASSEMBLY

(a) Turn the ignition switch to ON, and wait for at least 60 seconds.

(b) Clear the DTCs stored in memory (See page
).

(d) Turn the ignition switch to ON, and wait for at least 60 seconds.

(e) Check for DTCs (See page ).

OK:

DTC B161A is not output.

HINT:

Codes other than DTC B161A may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

Rear Airbag Sensor Assembly RH Initialization Incomplete (B1633/81,B1638/82)

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Lost Communication with Front Airbag Sensor LH (B1617/84,B1618/84)

DESCRIPTION The front airbag sensor LH circuit consists of the center airbag sensor and front airbag sensor LH. The front airbag sensor LH detects impacts to the vehicle and sends signals to the ...

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