SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DESCRIPTION (2008 Sequoia)

Last Modified: 11-29-2007		1.6 C
Service Category: Vehicle Interior	Section: Supplemental Restraint Systems
Model Year: 2008	Model: Sequoia	Doc ID: RM00000157W00AX
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DESCRIPTION (2008 Sequoia)

DTC

B1785

Front Occupant Classification Sensor LH Collision Detection

DESCRIPTION

DTC B1785 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the front occupant detection sensor LH when an accident occurs.

DTC B1785 is also stored when the front seat assembly RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is not in a collision, DTC B1785 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1785 is stored, first perform the zero point calibration and sensitivity check.

DTC Code	DTC Detection Condition	Trouble Area
B1785	Either of following conditions is met: Occupant classification ECU receives collision detection signal, which is sent by front occupant detection sensor LH when accident occurs Front seat assembly RH is subjected to strong impact, even if actual accident has not occurred	Front seat assembly RH (Front occupant detection sensor LH) Occupant classification ECU

HINT:

When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1785 of the occupant classification system.
Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

After the ignition switch is turned off, the navigation system requires approximately 90 seconds to record various types of memory and settings. As a result, after turning the ignition switch off, wait 90 seconds or more before disconnecting the cable from the negative (-) battery terminal.

PROCEDURE

1.	CHECK FOR DTC

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

(b) Clear any DTCs stored in the center airbag sensor .

(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 .

OK:

DTC B1785 is not output.

HINT:

DTCs other than DTC B1785 may be output at this time, but they are not related to this check.

2.	PERFORM ZERO POINT CALIBRATION

(a) Connect the Techstream to the DLC3.

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

3.	PERFORM SENSITIVITY CHECK

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

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

4.	CHECK FOR DTC

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

(b) Clear any DTCs stored in the center airbag sensor .

(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 .

OK:

DTC B1785 is not output.

HINT:

DTCs other than DTC B1785 may be output at this time, but they are not related to this check.

5.	REPLACE FRONT SEAT ASSEMBLY RH

(a) Turn the ignition switch off.

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

for Manual seat
for Power seat

HINT:

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

6.	PERFORM ZERO POINT CALIBRATION

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

(b) Connect the Techstream to the DLC3.

(d) Using the Techstream, perform the zero point calibration .

7.	PERFORM SENSITIVITY CHECK

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

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

8.	CHECK FOR DTC

(a) Connect the connectors to the occupant classification ECU and the front occupant detection sensor LH.

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

HINT:

First clear DTCs stored in the occupant classification ECU and then 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 off.

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

(f) Using the Techstream, check for DTCs of the occupant classification ECU .

OK:

DTC B1785 is not output.

HINT:

DTCs other than DTC B1785 may be output at this time, but they are not related to this check.

9.	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.

10.	PERFORM ZERO POINT CALIBRATION

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

(b) Connect the Techstream to the DLC3.

(d) Using the Techstream, perform the zero point calibration .

11.	PERFORM SENSITIVITY CHECK

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

Standard range:

27 to 33 kg (59.5 to 72.8 lb)