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DTC B1BBC: Occupant Classification System Negative System Weight


caution If DTC B1BBC is set in the occupant classification-ECU, always diagnose the CAN main bus lines.

CIRCUIT OPERATION


The load data from the weight sensor is classified with the occupant classification-ECU, and its classified information is send to SRS-ECU by CAN bus line. The SRS-ECU determines the air bag deployment based on this classified information, and controls the power supply circuit to the inflator.

DTC SET CONDITION


This DTC is set if the passenger seat weight is -15 Kg (-35 pound) or less.

TROUBLESHOOTING HINTS
An object is caught in between the passenger seat and floor.

DIAGNOSIS
Required Special Tools:
  • MB991958 Scan Tool (M.U.T.-III Sub Assembly)

    • MB991824: Vehicle Communication Interface (V.C.I.)
    • MB991827 M.U.T.-III USB Cable
    • MB991910 M.U.T.-III Main Harness A (Vehicles with CAN communication system)

STEP 1. Check for an object caught in between the passenger seat and floor.

Q. Is the check result normal?
Go to Step 2.
It corrects.

STEP 2. Using scan tool MB991958, diagnose the CAN bus line.
caution To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

(1)Connect scan tool MB991958. Refer to "How to connect the scan tool ."
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the CAN bus line found to be normal?

Go to Step 3.

Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).

STEP 3. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to the "ON" position.
(3)Check if the DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC B1BA7 set?
Replace the front seat cushion frame (RH) (Refer to GROUP 52A, Front Seat Assembly ) <Except RALLIART> or replace the slide adjuster (RH) (Refer to GROUP 52A, Front Seat Assembly ) <RALLIART>.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).