DTC 81: Side-Airbag Module (LH) (Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit): Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (MUT-III Sub Assembly)
  • MB991824: Vehicle Communication Interface (V.C.I.)
  • MB991827: MUT-III USB Cable
  • MB991911: MUT-III Main Harness B (Vehicles without CAN communication system)
• MB991865: Dummy resister
• MB991866: Resister harness

1. STEP 1. Using scan tool MB991958, read the diagnostic trouble code. 

   Q: Is DTC 34 set? 

   • YES:  Go to Step 2.
   • NO:  Go to  Step 3.
     Fig 1: Connecting Scan Tool To Data Link Connector

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Check SRS-ECU connector C-13. 

   Q: Is the connector correctly engaged? 

   • YES:  Go to Step 3.
   • NO:  Engage the connector correctly. Then go to  Step 7.
     Fig 2: Identifying Harness SRS-ECU Connector C-13

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Check SRS-ECU connector C-13 and side-airbag module (LH) connector D-19 (Using scan tool MB991958, read the diagnostic trouble code). 
   1. Disconnect the negative battery terminal.
   2. Disconnect connectors C-13 and D-19, and then reconnect them.
   3. Connect the negative battery terminal.
   4. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

   Q: Is DTC 81 out put? 

   • YES:  Go to Step 4.
   • NO:  The procedure is complete. It is assumed that DTC 81 set as connector C-13 or D-19 was engaged improperly.
     Fig 3: Identifying Harness SRS-ECU Connector C-13

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
     Fig 4: Identifying Harness Connector D-19

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check the side-airbag module (LH) (Using scan tool MB991958, read the diagnostic trouble code). 
   1. Disconnect the negative battery terminal.
   2. Disconnect the side-airbag module (LH) connector D-19.
      Fig 5: Identifying Harness Connector D-19

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   3. Connect special tool MB991865 to special tool MB991866.
      CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
   4. Insert special tool MB991866 into the D-19 harness connector by backprobing.
   5. Connect the negative battery terminal.
   6. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
      Fig 6: Checking Harness Connector D-19

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

   Q: Is DTC 81 set? 

   • YES:  Go to Step 5.
   • NO:  Replace the seat back assembly of the front seat (LH) (Refer to FRONT SEAT ASSEMBLY .) Then go to  Step 7.
5. STEP 5. Check the side-airbag module (LH) circuit at the SRS-ECU connector C-13. 
   1. Disconnect SRS-ECU connector C-13.
      Fig 7: Identifying Harness SRS-ECU Connector C-13

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

      DANGER 

      To prevents the air bag from deploying unintentionally, disconnect the side-airbag module (LH) connector D-19 to short the squib circuit. 

   2. Disconnect side-airbag module (LH) connector D-19.
      Fig 8: Identifying Harness Side-Airbag Module (LH) Connector D-19

      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.
   3. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between C-13 harness connector terminals 21, 22 and the short spring to release the short spring.
      Fig 9: Identifying Harness Connector C-13

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
   4. Check for continuity between terminals 21 and 22. It should be open circuit.

   Q: Is the circuit normal? 

   • YES:  Go to Step 6.
   • NO:  Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC 81 sets, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  .) Then go to  Step 7.
     Fig 10: Checking Continuity Between Terminals 21 And 22

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
6. STEP 6. Check the harness wires for short circuit between SRS-ECU connector C-13 (terminal No.21 and 22) and side-airbag module (LH) connector D-19 (terminal No.1 and 2.) 

   Q: Are the harness wires between SRS-ECU connector C-13 (terminal No.21 and 22) and side-airbag module (LH) connector D-19 (terminal No.1 and 2) in good condition? 

   • YES:  Go to Step 7.
   • NO:  Repair the harness wires between SRS-ECU connector C-13 and side-airbag module (LH) connector D-19. Then go to Step 7.
     Fig 11: Identifying Harness SRS-ECU Connector C-13

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
     Fig 12: Identifying Harness Connector D-19

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. CRecheck for diagnostic trouble code. 

   Q: Is DTC 81 set? 

   • YES:  Return to  Step 1.
   • NO:  The procedure is complete (If no malfunctions are found in all steps, an intermittent malfunction is suspected. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)