Toyota 4Runner: Sleep Operation Failure of Occupant Classification ECU (B1796)

Toyota 4Runner Service Manual / Vehicle Interior / Supplemental Restraint Systems / Occupant Classification System / Sleep Operation Failure of Occupant Classification ECU (B1796)

DESCRIPTION

During sleep mode, the occupant classification ECU monitors the condition of each sensor while the ignition switch is off. In this mode, if the occupant classification ECU detects an internal malfunction, DTC B1796 is stored.

DTC Code	DTC Detection Condition	Trouble Area
B1796	Occupant classification ECU malfunction.	Occupant classification ECU

HINT:

When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1796 of the occupant classification system.
Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

PROCEDURE

1.	CHECK FOR DTC

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

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

HINT:

First clear the DTCs stored in the occupant classification ECU, and then clear the DTCs stored in the center airbag sensor.
Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.

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

(e) Using the Techstream, check for DTCs of the occupant classification ECU (See page ).

OK:

DTC B1796 is not output.

HINT:

DTCs other than DTC B1796 may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

2.	REPLACE OCCUPANT CLASSIFICATION ECU

(a) Turn the ignition switch off.

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

HINT:

Perform the inspection using parts from a normal vehicle when possible.

3.	PERFORM ZERO POINT CALIBRATION

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

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

OK:

"Zero Point Calibration is complete." is displayed.

4.	PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check (See page ).

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

END

Occupant Classification ECU Malfunction (B1795)

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DIAGNOSTIC TROUBLE CODE CHART HINT: When DTC B1650/32 is stored as a result of troubleshooting for the airbag system, perform troubleshooting for the occupant classification system as ...

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