DTC B1603: Seat belt pre-tensioner (driver's side) (squib) system (short circuit between squib circuit terminals): Diagnosis

WARNING: This page is about a different car, the 2014 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.

STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus line.
CAUTION: To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
1. Connect scan tool (M.U.T.-III). 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?
1. YES: Go to Step 2.
2. NO: Repair the CAN bus line (Refer to DIAGNOSIS ).
STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is stored.
1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is stored.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC stored?
1. YES: Go to Step 3.
2. 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. Connector check: SRS-ECU connector, seat belt pre-tensioner (driver's side) connector.
1. Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
2. While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever. After disconnecting the SRS-ECU connector, connect it again.
  
  Fig 1: Disconnecting SRS-ECU Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. After disconnecting the SRS-ECU harness side connector, connect the connector again. For the seat belt pre-tensioner (driver's side) harness side connector disconnection, use the flat-tipped screwdriver to pull out the harness side connector locking button. After releasing the lock, disconnect the harness side connector.
4. Connect the negative battery terminal.
5. After erasing the DTC memory, check the DTC again.
6. Disconnect the negative battery terminal.
Q: Is DTC B1603 stored?
1. YES: Go to Step 4.
2. NO: Replace the connector concerned.
  
  Fig 2: Pulling Out Locking Button Of Harness Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 4. Diagnosis check by dummy resistor connection.
1. Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
2. Use the flat-tipped screwdriver to pull out the locking button of harness side connector. After releasing the lock, disconnect the seat belt pre-tensioner (driver's side) harness side connector.
  
  Fig 3: Pulling Out Locking Button Of Harness Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
4. Connect special tool resistor harness to the seat belt pre-tensioner (driver's side) harness side connector.
5. Connect the negative battery terminal.
6. After erasing the DTC memory, check the DTC again.
7. Disconnect the negative battery terminal.
Q: Is DTC B1603 stored?
1. YES: Go to Step 5.
2. NO: Replace the seat belt with pre-tensioner (driver's side) (Refer to SEAT BELTS WITH PRE-TENSIONER ).
  
  Fig 4: Identifying Harness Side Connector And Special Tools
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 5. Resistance check at the SRS-ECU connector (PTD+, PTD- line).
1. Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
2. While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the SRS-ECU connector.
  WARNING: To release the SRS-ECU connector short spring in the following operations, disconnect this seat belt pre-tensioner connector, and keep the squib circuit shorted.
  
  Fig 5: Disconnecting SRS-ECU Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Use the flat-tipped screwdriver to pull out the locking button of harness side connector. After releasing the lock, disconnect the seat belt pre-tensioner (RH) harness side connector.
  
  Fig 6: Pulling Out Locking Button Of Harness Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  
  CAUTION: The short spring may not be released due to the insufficient insertion. Therefore, insert the insulator for 4 mm (0.16 inch) or more.
4. Insert an insulator [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] such as cable tie PTD+, PTD- line between the SRS-ECU connector and the seat belt pre-tensioner (RH) connector.
5. Take the measurements below at the SRS-ECU harness side connector.
  - Continuity PTD+, PTD- line between the SRS-ECU connector and the seat belt pre-tensioner (RH) connector.
    OK: No continuity
    
    Fig 7: Identifying Harness Side Connector And Cable Tie
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Is the check result normal?
1. YES: Go to Step 6.
2. NO: Repair the wiring harness PTD+, PTD- line between the SRS-ECU connector and the seat belt pre-tensioner (RH) connector.
STEP 6. Recheck for diagnostic trouble code.
Check again if the DTC is stored.
1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is stored.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1603 stored?
1. YES: Replace SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU) ).
2. NO: Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).