DTC B1C3B: Driver's Seat belt Pre-tensioner (Squib) System (Short Circuit Between Squib Circuit Terminals): 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)
- MB991865: Dummy resistor
- MB991884: Resister harness
- STEP 1. 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.
- Connect scan tool MB991958. Refer to "HOW TO CONNECT THE SCAN TOOL ."
- Turn the ignition switch to the "ON" position.
- Diagnose the CAN bus line.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
- YES: Go to Step 2.
- NO: Repair the CAN bus line (Refer to DIAGNOSIS ).
- STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is stored.
- Erase the DTC.
- Turn the ignition switch to "ON" position.
- Check if the DTC is stored.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC stored?
- YES: Go to Step 3.
- NO: There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
- STEP 3. Check SRS-ECU connector C-30 and driver's seat belt pre-tensioner connector D-21.
- Disconnect the negative battery terminal.
- While pressing the part A in the illustration of the C-30 SRS-ECU harness side connector, turn the lock lever toward the arrow direction to release the lock lever. Then, disconnect the connector and reconnect it.
- Disconnect D-21 driver's pretensioner harness side connector, and then reconnect it. Use a flat-tipped (-) screwdriver to pull out the connector locking button toward the arrow direction, release the lock, and then disconnect the connector.
- Connector the negative battery terminal.
- Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
Q: Is DTC B1C3B stored?
- YES: Go to Step 4.
- NO: The procedure is complete. It is assumed that DTC B1C3B is stored because connector C-30 or D-21 was engaged improperly.
- STEP 4. Check the driver's seat belt pre-tensioner.
- Disconnect the negative battery terminal.
- While pushing the part "A" indicated in the illustration of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-30 SRS-ECU connector.
- Disconnect driver's seat belt pre-tensioner connector D-21. Use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.
- Connect special tool MB991865 to special tool MB991884.
- Connect special tool MB991884 to the D-21 harness side connector.
- Connect the negative battery terminal.
- Erase diagnostic trouble code memory, and then check the diagnostic trouble code.
Q: Is DTC B1C3B stored?
- YES: Go to Step 5.
- NO: Replace the driver's seat with belt pre-tensioner (Refer to SEAT BELTS WITH PRE-TENSIONER ). Then go to Step 7.
- STEP 5. Check the driver's seat belt pre-tensioner circuit. Measure the resistance at the SRS-ECU connector C-30.
- Disconnect the negative battery terminal.
- While pushing the part "A" indicated in the illustration
of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-30 SRS-ECU connector.
WARNING: To prevent the seat belt pre-tensioner from deploying unintentionally, disconnect the driver's seat belt pre-tensioner connector D-21 to short the squib circuit.
- Disconnect driver's seat belt pre-tensioner connector D-21. Use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
CAUTION: Insert an insulator such as a cable tie to a depth of 4mm (0.16 inch) or more, otherwise the short spring will not be released. - Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminals 45, 46 and the short spring to release the short spring.
- Check for continuity between C-30 harness side connector terminals 45 and 46. It should be an open circuit.
Q: Is it open circuit?
- YES: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1C3B is stored, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU) ). Then go to Step 7.
- NO: Go to Step 6.
- STEP 6. Check the harness for short circuit between SRS-ECU connector C-30 (terminal No. 45 and 46) and driver's seat belt pre-tensioner connector D-21 (terminal No. 1 and 2).
Q: Is the check result normal?
- YES: Go to Step 7.
- NO: Repair the harness wires between SRS-ECU connector C-30 and driver's seat belt pre-tensioner connector D-21. Then go to Step 7.
- STEP 7. Recheck for diagnostic trouble code.
Check again if the DTC is stored.
- Erase the DTC.
- Turn the ignition switch to the "ON" position.
- Check if the DTC is stored.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1C3B stored?
- YES: Return to Step 1.
- NO: The procedure is complete.