DTC 22: Driver's Air Bag Module (Squib) System Fault 2 (Open in the Squib Circuit): Diagnosis

Required Special Tools:

MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface
- MB991827: MUT-III USB Cable
- MB991911: MUT-III Main Harness B
MB991613: SRS Check Harness
MB991865: Dummy resister
MB991866: Resister harness

STEP 1. Check the driver's air bag module (Using scan tool MB991958, read the diagnostic trouble code).
1. Disconnect the negative battery terminal.
2. Remove the driver's air bag module (Refer to INSPECTION ).
3. Connect connector (4) of special tool MB991613 to clock spring connector C-81.
  
  Fig 1: Connecting Connector Of Special Tool MB991613 To Clock Spring Connector C-81
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Connect connector (1) of special tool MB991613 to connector (2).
5. Connect terminals 22 to 24, and terminals 23 to 25 of special tool MB991613 to connector (5).
6. Connect the clock spring to the body wiring harness.
7. Connect the negative battery terminal.
8. Erase the DTC memory, and then recheck the DTC.
Q: Is DTC 22 set?
1. YES: Go to Step 2.
2. NO: Replace the driver's air bag module. Refer to INSPECTION . Then go to Step 4.
STEP 2. Check the clock spring (Using scan tool MB991958, read the diagnostic trouble code).
1. Disconnect the negative battery terminal.
2. Disconnect the clock spring connector C-85.
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.
  
  Fig 2: Inserting Special Tool MB991866 Into Clock Spring Harness Side Connector C-85
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Insert special tool MB991866 into clock spring harness side connector C-85 (terminal No. 3 and 4) by backprobing.
5. Connect the negative battery terminal.
6. Erase the DTC memory, and then recheck DTC.
Q: Is DTC 22 set?
1. YES: Go to Step 3.
2. NO: Replace the clock spring. Refer to INSPECTION . Then go to Step 4.
STEP 3. Check the harness between the SRS-ECU and the clock spring for open circuit.
1. Disconnect SRS-ECU connector C-72 and clock spring connector C-85, and measure at the wiring harness side.
  CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
  
  Fig 3: Identifying SRS-ECU C-72 Connector Terminal
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  
  Fig 4: Identifying Clock Spring C-85 Connector Terminal
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. Check for continuity between the following terminals.
  - SRS-ECU connector C-72 (terminal No. 7) and the clock spring connector C-85 (terminal No. 3)
  - SRS-ECU connector C-72 (terminal No. 8) and the clock spring connector C-85 (terminal No. 4)
  - Should be less than 2 ohms.
  Fig 5: Checking Continuity Between SRS-ECU C-72 And Clock Spring C-85 Connector Terminals
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Does continuity exist?
1. YES: Eras the DTC memory, and recheck if any DTC sets. If DTC 22 sets, replace the SRS-ECU. Refer to HARNESS CONNECTOR . Then go to Step 4.
2. NO: Repair the harness wires between SRS-ECU connector C-72 and clock spring connector C-85. Then go to Step 4.
STEP 4. Recheck for diagnostic trouble code.
Q: Is DTC 22 set?
1. YES: Return to Step 1.
2. 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 MALFUNCTIONS ).