SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DESCRIPTION (2008 LX570)

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Last Modified: 11-27-2007		1.6 J
Service Category: Vehicle Interior	Section: Supplemental Restraint Systems
Model Year: 2008	Model: LX570	Doc ID: RM000001P3800WX
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DESCRIPTION (2008 LX570)

Trouble in Passenger Airbag ON/OFF Indicator

DESCRIPTION

The occupant classification system detects the front passenger seat condition. It then informs a passenger of the front passenger airbag and front seat side airbag condition (activated/not activated) by the passenger airbag ON/OFF indicator.

HINT:

Approximately 6 seconds after the engine switch is turned on (IG), the passenger airbag ON/OFF indicator will be ON/OFF depending on the conditions listed below.

Front Passenger Seat Condition	Passenger Airbag ON/OFF Indicator		SRS Warning Light
Front Passenger Seat Condition	ON Indicator	OFF Indicator	SRS Warning Light
Adult is seated	On	Off	Off
Child is seated	Off	On	Off
Vacant	Off	Off	Off
Occupant classification system failure	Off	On	On

INSPECTION PROCEDURE

NOTICE:

w/ Navigation system:

After the engine switch is turned off, the HDD navigation system requires approximately 6 minutes to record various types of memory and settings. As a result, after turning the engine switch off, wait 6 minutes or more before disconnecting the cable from the negative (-) battery terminal.

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

HINT:

When the indicator is malfunctioning, if the SRS warning light is off, follow the procedures below as a DTC is not output. If the SRS warning light is on, a DTC is output. Troubleshoot for the output DTC.

PROCEDURE

1.	PERFORM ZERO POINT CALIBRATION

(a) Connect the Techstream to the DLC3.

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

(d) Turn the engine switch off.

(e) Turn the engine switch on (IG).

(f) Check for DTCs of the occupant classification ECU .

2.	CHECK FOR DTC

(a) Turn the engine switch on (IG).

(b) Clear the DTCs stored in the occupant classification ECU .

(d) Turn the engine switch off.

(e) Turn the engine switch on (IG).

(f) Check for DTCs .

OK:

DTC B1797 is not output.

HINT:

Codes other than DTC B1797 may be output at this time, but they are not related to this check.

3.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR (PERFORM SENSITIVITY CHECK)

(a) Perform the sensitivity check .

(b) Check the passenger airbag ON/OFF indicator .

4.	READ VALUE USING TECHSTREAM (PASSENGER SIDE BUCKLE SWITCH)

(a) Turn the engine switch on (IG).

(b) Using the Techstream, read the "Data List" .

(1) Read the display when the passenger side buckle switch is operated.

Occupant Detection

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Passenger Buckle SW

Buckle switch (Passenger side) / Unset, Set or NG

Set: The seat belt fastened

Unset: The seat belt not fastened

NG: Data not determined

OK:

Tester display changes correctly in accordance with the operation of the buckle switch.

5.	READ VALUE USING TECHSTREAM (SEAT BELT TENSION SENSOR)

(a) Fasten the passenger side seat belt.

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

Occupant Detection

Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
Filtered belt tension output	Filtered belt tension output / Min.: 0, Max.: 255	39 to 229	-

OK:

When there is no tension on belt, 39 to 229 is displayed on the Techstream.

6.	CHECK CONNECTOR

(a) Disconnect the connectors from the occupant classification ECU and the detection sensor.

(b) Check that the connectors (on the center airbag sensor side and occupant detection sensor side) are not damaged.

OK:

Connectors are not deformed or damaged.

7.	REPLACE NO. 1 SEAT CUSHION ASSEMBLY (OCCUPANT CLASSIFICATION ECU)

(a) Connect the Techstream to the DLC3.

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

(d) Turn the engine switch off.

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

(f) Replace the No. 1 seat cushion (occupant classification ECU) .

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

(h) Turn the engine switch on (IG).

(i) Using the Techstream, load the previous ECU data stored in the Techstream into the new ECU .

8.	PERFORM ZERO POINT CALIBRATION

(a) Connect the Techstream to the DLC3.

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

9.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR (PERFORM SENSITIVITY CHECK)

(a) Perform the sensitivity check .

(b) Check the passenger airbag ON/OFF indicator .

10.	CHECK CONNECTOR

(a) Disconnect the connectors from the occupant classification ECU and front seat inner belt RH.

(b) Check that the connectors (on the center airbag sensor side and front seat inner belt RH side) are not damaged.

OK:

Connectors are not deformed or damaged.

11.	REPLACE FRONT SEAT INNER BELT ASSEMBLY RH

(a) Turn the engine 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.

12.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR (PERFORM SENSITIVITY CHECK)

(a) Perform the sensitivity check .

(b) Check the passenger airbag ON/OFF indicator .

13.	CHECK CONNECTOR

(a) Disconnect the connectors from the occupant classification ECU and the belt tension sensor.

(b) Check that the connectors (on the center airbag sensor side and seat belt tension sensor side) are not damaged.

OK:

Connectors are not deformed or damaged.

14.	REPLACE FRONT SEAT OUTER BELT ASSEMBLY RH (SEAT BELT TENSION SENSOR)

(a) Turn the engine 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.

15.	CHECK PASSENGER AIRBAG ON/OFF INDICATOR (PERFORM SENSITIVITY CHECK)

(a) Perform the sensitivity check .

(b) Check the passenger airbag ON/OFF indicator .