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DTC B1BBA: Passenger Seat Weight Sensor Power Supply Circuit
 
 
cautionIf DTC B1BBA 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 CONDITIONS
This DTC is set if the weight sensor power supply line is defective.
 
 
TROUBLESHOOTING HINTS
  • The weight sensor may be defective.
  • The occupant classification-ECU may be defective.
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
cautionTo 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.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. 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.
Is the DTC set?
Go to Step 3.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 3. Using scan tool MB991958,read the occupant classification-ECU diagnostic trouble code.
Check if the DTC B210D or B210E is set the occupant classification-ECU.
Is the DTC B1B78, B1B7D, B1B82 or B1B87 set?
Diagnose the occupant classification-ECU (Refer to ).
Replace the passenger seat cushion frame assembly (Refer to GROUP 52A, Front Seat Assembly ).