B1785

SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: B1785: Front Occupant Classification Sensor LH Collision Detection
B1785 - Front Occupant Classification Sensor LH Collision Detection

DESCRIPTION

DTC B1785 is set 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 set when the front seat frame with adjuster 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 set, first perform the zero point calibration and sensitivity check.





HINT
- When DTC B1650/32 is set 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

PROCEDURE

1. CHECK FOR DTC

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

(b) Clear any DTCs stored in the center airbag sensor Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the ignition switch OFF.

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

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

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.

NG -- PERFORM ZERO POINT CALIBRATION

OK -- USE SIMULATION METHOD TO CHECK Diagnosis System

2. PERFORM ZERO POINT CALIBRATION

(a) Connect the Techstream to the DLC3.

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

(c) Using the Techstream, perform the zero point calibration Programming and Relearning.

NG -- REPLACE FRONT SEAT FRAME WITH ADJUSTER ASSEMBLY RH
OK -- Continue to next step.

3. PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check Programming and Relearning.

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

NG -- REPLACE FRONT SEAT FRAME WITH ADJUSTER ASSEMBLY RH
OK -- Continue to next step.

4. CHECK FOR DTC

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

(b) Clear any DTCs stored in the center airbag sensor Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the ignition switch OFF.

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

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

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.

NG -- REPLACE FRONT SEAT FRAME WITH ADJUSTER ASSEMBLY RH

OK -- END

5. REPLACE FRONT SEAT FRAME WITH ADJUSTER ASSEMBLY RH

(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 front seat frame with adjuster RH Removal.

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

NEXT -- Continue to next step.

6. PERFORM ZERO POINT CALIBRATION

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

(b) Connect the Techstream to the DLC3.

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

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

NG -- REPLACE OCCUPANT CLASSIFICATION ECU
OK -- Continue to next step.

7. PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check Programming and Relearning.

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

NG -- REPLACE OCCUPANT CLASSIFICATION ECU
OK -- Continue to next step.

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 ON, and wait for at least 60 seconds.

(c) Clear any DTCs stored in the memory Reading and Clearing Diagnostic Trouble Codes.

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 ON, and wait for at least 60 seconds.

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

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.

NG -- REPLACE OCCUPANT CLASSIFICATION ECU

OK -- END

9. 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.

* for Manual Seat Disassembly

* for Power Seat Disassembly

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

NEXT -- Continue to next step.

10. PERFORM ZERO POINT CALIBRATION

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

(b) Connect the Techstream to the DLC3.

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

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

NEXT -- Continue to next step.

11. PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check Programming and Relearning.

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

NEXT -- END