B1785

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

DTC B1785 - Front Occupant Classification Sensor LH Collision Detection

DESCRIPTION

DTC B1785 is output when the occupant classification ECU receives a collision detection signal sent by the front occupant classification sensor LH if an accident occurs.
DTC B1785 is also output when the front seat adjuster frame assembly RH is subjected to a strong impact, even if an actual accident does not occur.
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 "zero point calibration" and "sensitivity check".
Therefore, if DTC B1785 is output, first perform "zero point calibration" and "sensitivity check".





HINT: When DTC B1650/32 is detected as a result of troubleshooting for "AIRBAG SYSTEM", check the DTCs stored in the occupant classification ECU. When DTC B1785 is output, perform troubleshooting for the DTC.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ZERO POINT CALIBRATION
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Using the Techstream, perform "zero point calibration" Programming and Relearning.
OK:
"Zero Point Calibration is complete." is displayed.
NG -- REPLACE FRONT SEAT ASSEMBLY RH
OK -- Continue to next step.
2. PERFORM SENSITIVITY CHECK
(a) Using the Techstream, perform "sensitivity check" Programming and Relearning.
Standard values:
27 to 33 kg (59.52 to 72.75 lb)
NG -- REPLACE FRONT SEAT ASSEMBLY RH
OK -- Continue to next step.
3. CHECK DTC
(a) Turn the ignition switch to the ON position.
(b) Clear the DTCs stored in the memory Reading and Clearing Diagnostic Trouble Codes.
HINT: First clear the DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
(c) Turn the ignition switch to the LOCK position.
(d) Turn the ignition switch to the ON position.
(e) Check the DTCs Reading and Clearing Diagnostic Trouble Codes.
OK:
DTC B1785 is not output.
HINT: Codes other than DTC B1785 may be output at this time, but they are not related to this check.

NG -- REPLACE FRONT SEAT ASSEMBLY RH
OK -- END
4. REPLACE FRONT SEAT ASSEMBLY RH
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery.
(c) Replace the front seat assembly RH Removal.
HINT: Perform the inspection using parts from a normal vehicle if possible.

NEXT -- Continue to next step.
5. 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 to the ON position.
(d) Using the Techstream, perform "zero point calibration" Programming and Relearning.
OK:
"Zero Point Calibration is complete." is displayed.
NG -- REPLACE OCCUPANT CLASSIFICATION ECU
OK -- Continue to next step.
6. PERFORM SENSITIVITY CHECK
(a) Using the Techstream, perform "sensitivity check" Programming and Relearning.
Standard values:
27 to 33 kg (59.52 to 72.75 lb)
NG -- REPLACE OCCUPANT CLASSIFICATION ECU
OK -- Continue to next step.
7. CHECK DTC
(a) Turn the ignition switch to the ON position.
(b) Clear the DTCs stored in the memory Reading and Clearing Diagnostic Trouble Codes.
HINT: First clear the DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
(c) Turn the ignition switch to the LOCK position.
(d) Turn the ignition switch to the ON position.
(e) Check the DTCs Reading and Clearing Diagnostic Trouble Codes.
OK:
DTC B1785 is not output.
HINT: Codes 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
8. REPLACE OCCUPANT CLASSIFICATION ECU
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery.
(c) Replace the occupant classification ECU Removal.
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 to the ON position.
(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" Programming and Relearning.
Standard values:
27 to 33 kg (59.52 to 72.75 lb)
NEXT -- END