Occupant Classification System (from 12/2010)

SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: B1790: Center Airbag Sensor Assembly Communication Circuit Malfunction
B1790 - Center Airbag Sensor Assembly Communication Circuit Malfunction

DESCRIPTION

The center airbag sensor assembly communication circuit consists of the occupant classification ECU and the center airbag sensor assembly.

DTC B1790 is recorded when a malfunction is detected in the center airbag sensor assembly communication circuit.





WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
* If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see the under surface of seat cushion.
* In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may cause a problem, such as seat rail deformation. Hold the seat only as necessary.

PROCEDURE

1. CHECK DTC

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

(b) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(c) Clear the DTCs stored in the center airbag sensor assembly DTC Check / Clear (from 12/2010).

(d) Turn the ignition switch off.

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

(f) Check the DTCs Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC B1790 is not output.

HINT
Codes other than DTC B1790 may be output at this time, but they are not related to this check.

OK -- USE SIMULATION METHOD TO CHECK
NG -- Continue to next step.

2. CHECK CONNECTION OF CONNECTORS

(a) Turn the ignition switch off.

(b) Disconnect the negative (-) terminal cable from the battery.

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

OK:

The connectors are properly connected.

NG -- CONNECT CONNECTORS PROPERLY, THEN GO TO STEP 1
OK -- Continue to next step.

3. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (SHORT TO B+)

(a) Disconnect the connector from the center airbag sensor assembly and occupant classification ECU.





(b) Connect the negative (-) terminal cable to the battery.

(c) Turn the ignition switch on (IG).

(d) Measure the voltage according to the value(s) in the table below.

Standard voltage:





NG -- CHECK FLOOR WIRE NO. 2 (SHORT TO B+)
OK -- Continue to next step.

4. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (OPEN)

(a) Turn the ignition switch off.





(b) Disconnect the negative (-) terminal cable from the battery.

(c) Using a service wire, connect terminals 12 (FSP+) and 13 (FSP-) of connector B.

NOTICE:
Do not forcibly insert a service wire into the terminals of the connector when connecting.

(d) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- CHECK FLOOR WIRE NO. 2 (OPEN)
OK -- Continue to next step.

5. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (SHORT)

(a) Disconnect the service wire from connector B.





(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- CHECK FLOOR WIRE NO. 2 (SHORT)
OK -- Continue to next step.

6. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (SHORT TO GROUND)

(a) Measure the resistance according to the value(s) in the table below.





Standard resistance:





NG -- CHECK FLOOR WIRE NO. 2 (SHORT TO GROUND)
OK -- Continue to next step.

7. RECHECK DTC

(a) Connect the connectors to the occupant classification ECU and the center airbag sensor assembly.

(b) Connect the Techstream to the DLC3.

(c) Connect the negative (-) terminal cable to the battery.

(d) Turn the ignition switch on (IG).

(e) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(f) Clear the DTCs stored in the center airbag sensor assembly DTC Check / Clear (from 12/2010).

(g) Turn the ignition switch off.

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

(i) Using the Techstream, check the DTCs of the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC B1790 is not output.

HINT
Codes other than DTC B1790 may be output at this time, but they are not related to this check.

OK -- USE SIMULATION METHOD TO CHECK
NG -- Continue to next step.

8. REPLACE OCCUPANT CLASSIFICATION ECU

(a) Turn the ignition switch off.

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

(c) Replace the occupant classification ECU Removal (from 12/2010).

HINT
Perform the inspection using parts from a normal vehicle if possible.

NEXT -- Continue to next step.

9. PERFORM ZERO POINT CALIBRATION

(a) Connect the negative (-) terminal cable to the battery.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch on (IG).

(d) Using the Techstream, perform "Zero point calibration" Programming and Relearning.

OK:

"Zero Point Calibration is complete." is displayed.

NEXT -- Continue to next step.

10. PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform "Sensitivity check" Reading and Clearing Diagnostic Trouble Codes.

Standard value:

27 to 33 kg (59.52 to 72.75 lb)

NEXT -- Continue to next step.

11. RECHECK DTC

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

(b) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

(c) Clear the DTCs stored in the center airbag sensor assembly DTC Check / Clear (from 12/2010).

(d) Turn the ignition switch off.

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

(f) Using the Techstream, check the DTCs of the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC B1790 is not output.

HINT
Codes other than DTC B1790 may be output at this time, but they are not related to this check.

NG -- REPLACE CENTER AIRBAG SENSOR ASSEMBLY Removal (from 12/2010)

OK -- END

12. CHECK FLOOR WIRE NO. 2 (SHORT TO B+)

(a) Turn the ignition switch off.





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

(c) Disconnect the front seat wire RH connector from the floor wire No. 2.

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

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

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

Standard voltage:





NG -- REPAIR OR REPLACE FLOOR WIRE NO. 2

OK -- REPAIR OR REPLACE FRONT SEAT WIRE RH

13. CHECK FLOOR WIRE NO. 2 (OPEN)

(a) Disconnect the front seat wire RH connector from the floor wire No. 2.





HINT
The service wire has already been inserted into connector B.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- REPAIR OR REPLACE FLOOR WIRE NO. 2

OK -- REPAIR OR REPLACE FRONT SEAT WIRE RH

14. CHECK FLOOR WIRE NO. 2 (SHORT)

(a) Disconnect the front seat wire RH connector from the floor wire No. 2.





(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- REPAIR OR REPLACE FLOOR WIRE NO. 2

OK -- REPAIR OR REPLACE FRONT SEAT WIRE RH

15. CHECK FLOOR WIRE NO. 2 (SHORT TO GROUND)

(a) Disconnect the front seat wire RH connector from the floor wire No. 2.





(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- REPAIR OR REPLACE FLOOR WIRE NO. 2

OK -- REPAIR OR REPLACE FRONT SEAT WIRE RH