DTC 72: Side-Airbag Module (RH) (Squib) System Fault 2 (Open in 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. Check the side-airbag module (RH) (Using scan tool MB991958, read the diagnostic trouble code). 
   1. Disconnect the negative battery terminal.
   2. Disconnect the side-airbag module (RH) connector D-27.
      Fig 1: Identifying Side-Airbag Module (RH) Connector D-27

      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-27 harness connector by backprobing.
   5. Connect the negative battery terminal.
   6. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

   Q: Is DTC 72 set? 

   • YES:  Go to Step 2.
   • NO:  Replace the seat back assembly of the front seat (RH) (Refer to FRONT SEAT ASSEMBLY .) Then go to  Step 3.
     Fig 2: Checking Harness Connector D-27

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Check the harness for open circuit between SRS-ECU connector C-13 (terminal No.23 and 24) and the side-airbag module (RH) connector D-27 (terminal No.1 and 2.) 
   1. Disconnect SRS-ECU connector C-13 and side-airbag module (RH) connector D-27.
      Fig 3: Identifying Harness SRS-ECU Connector C-13

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      Fig 4: Identifying Harness Connector D-27

      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.
   2. Check for continuity between the following terminals.
      • SRS-ECU connector C-13 (terminal No.23) and the side-airbag module (RH) connector D-27 (terminal No.2)
      • SRS-ECU connector C-13 (terminal No.24) and the side-airbag module (RH) connector D-27 (terminal No.1)

      It should be less than 2 ohms.

      Fig 5: Checking Continuity Between C-13 Harness Connector Terminals 23 And 24

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

   Q: Does continuity exist? 

   • YES:  Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC 72 sets, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  .) Then go to Step 3.
   • NO:  Repair the harness wires between SRS-ECU connector C-13 and side-airbag module (RH) connector D-27. Then go to Step 3.
3. STEP 3. Recheck for diagnostic trouble code. 

   Q: Is DTC 72 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 .)