DTC C2104: Faulty valve power supply circuit: 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
• MB991997: ASC check harness

1. STEP 1. Using scan tool MB991958, diagnose the CAN bus lines. 

   Use scan tool to diagnose the CAN bus lines.

   Q: Is the check result normal? 

   1. YES:  Go to  Step 3.
   2. NO:  Repair the CAN bus lines (Refer to CAN BUS DIAGNOSTICS TABLE ). On completion, go to Step 2.
2. STEP 2. DTC recheck after resetting CAN bus lines 

   Q: Is DTC C2104 set? 

   1. YES:  Go to Step 3.
   2. NO:  The procedure is complete.
3. STEP 3. Battery check 

   Refer to BATTERY TEST .

   Q: Is the battery in good condition? 

   1. YES:  Go to  Step 5.
   2. NO:  Replace the battery. Then go to Step 4.
4. STEP 4. Charging system check 

   Refer to GENERATOR OUTPUT LINE VOLTAGE DROP TEST .

   Q: Is the charging system in good condition? 

   1. YES:  Go to Step 5.
   2. NO:  Repair or replace the charging system component(s). Then go to  Step 11.
5. STEP 5. Connector check: A-51 ASC-ECU connector 

   Q: Is the check result normal? 

   1. YES:  Go to Step 6.
   2. NO:  Repair the defective connector. Then go to  Step 11.
6. STEP 6. Fusible link check: Check the fusible link No. 27. 

   Visually check for open circuit in the fusible link No. 27.

   Q: Is the check result normal? 

   1. YES:  Go to  Step 8.
   2. NO:  Go to Step 7.
7. STEP 7. Resistance measurement at A-51 ASC-ECU connector 
   1. Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the resistance at the special tool connector side.
      NOTE: Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
   2. Disconnect the fusible link No. 27.
   3. Measure the resistance between the terminal No. 32 and the body ground.

      OK: No continuity 

   Q: Is the check result normal? 

   1. YES:  Replace the fusible link No. 27. Then go to  Step 11.
   2. NO:  The short circuit may be present in the power supply circuit. Repair the wiring harness between the A-51 ASC-ECU connector terminal No. 32 and the fusible link No. 27, and then replace the fusible link No. 27. Then go to  Step 11.
      Fig 1: Measuring Resistance Between Terminal No. 32 And Body Ground

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
8. STEP 8. Voltage measurement at the A-51 ASC-ECU connector 
   1. Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the voltage at the special tool connector side.
      NOTE: Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
   2. Measure the voltage between the terminal No. 32 and the body ground.

      OK: Approximately system voltage 

   Q: Is the check result normal? 

   1. YES:  Go to Step 9.
   2. NO:  The open circuit may be present in the power supply circuit. Repair the wiring harness between the A-51 ASC-ECU connector terminal No. 32 and the fusible link No. 27. Then go to  Step 11.
      Fig 2: Measuring Voltage Between Terminal No. 32 And Body Ground

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
9. STEP 9. Resistance measurement at A-51 ASC-ECU connector 
   1. Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the resistance at the special tool connector side.
      NOTE: Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
   2. Measure the resistance between the terminal No. 16 and the body ground, and between the terminal No. 47 and the body ground.

      OK: Continuity exists (2 Ω or less) 

   Q: Is the check result normal? 

   1. YES:  Go to Step 10.
   2. NO:  An open circuit may be present in the ground circuit. Repair the wiring harness between the A-51 ASC-ECU connector terminal No. 16 and the body ground, and between the A-51 ASC-ECU connector terminal No. 47 and the body ground. Then go to  Step 11.
      Fig 3: Measuring Resistance Between Terminal No. 16 And Body Ground

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
10. STEP 10. Check whether the DTC is reset. 

    Q: Is DTC C2104 set? 

    1. YES:  Replace the hydraulic unit (integrated with ASC-ECU) (Refer to HYDRAULIC UNIT  ). Then go to Step 11.
    2. NO:  Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).
11. STEP 11. Check whether the DTC is reset. 

    Q: Is DTC C2104 set? 

    1. YES:  Return to  Step 1.
    2. NO:  The procedure is complete.