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: RM00000158600AX
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DESCRIPTION (2008 Sequoia)

DTC

B1794

Open in Occupant Classification ECU Battery Positive Line

DESCRIPTION

DTC B1794 is stored when a malfunction is detected in the occupant classification ECU.

DTC Code	DTC Detection Condition	Trouble Area
B1794	One of following conditions is met: Occupant classification ECU circuit malfunction Occupant classification ECU malfunction Occupant classification ECU receives short circuit to ground signal in passenger side buckle switch circuit for 2 seconds	Harness or connector Occupant classification ECU

HINT:

When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1794 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 memory .

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 to ON, and wait for at least 60 seconds.

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

OK:

DTC B1794 is not output.

HINT:

DTCs other than DTC B1794 may be output at this time, but they are not related to this check.

2.	CHECK CONNECTION OF CONNECTOR

(a) Turn the ignition switch off.

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

(c) Check that the connectors are properly connected to the center airbag sensor, occupant detection sensors and occupant classification ECU.

OK:

Connectors are properly connected.

3.	CHECK CONNECTOR

(a) Check that the connectors (on the occupant classification ECU side) are not damaged .

OK:

Connectors are not deformed or damaged.

4.	CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE)

(a) Turn the ignition switch off.

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

HINT:

*1: for Power Seat

*2: for Manual Seat

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

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

(f) Measure the resistance and voltage according to the value(s) in the table below.

Standard Resistance:

for Power Seat

Tester Connection	Condition	Specified Condition
W6-3 (GND) - Body ground	Always	Below 1 Ω

for Manual Seat

Tester Connection	Condition	Specified Condition
P14-3 (GND) - Body ground	Always	Below 1 Ω

Standard Voltage:

for Power Seat

Tester Connection	Switch Condition	Specified Condition
W6-1 (+B) - Body ground	Ignition switch ON	11 to 14 V
W6-7 (IG) - Body ground	Ignition switch ON	11 to 14 V

for Manual Seat

Tester Connection	Switch Condition	Specified Condition
P14-1 (+B) - Body ground	Ignition switch ON	11 to 14 V
P14-7 (IG) - Body ground	Ignition switch ON	11 to 14 V

5.	CHECK FOR DTC

(a) Turn the ignition switch off.

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

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

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

(f) Clear any DTCs stored in the memory .

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.

(g) Turn the ignition switch off, and wait for at least 10 seconds.

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

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

OK:

DTC B1794 is not output.

HINT:

DTCs other than DTC B1794 may be output at this time, but they are not related to this check.

6.	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.

7.	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 .

8.	PERFORM SENSITIVITY CHECK

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

Standard range:

27 to 33 kg (59.5 to 72.8 lb)