Inspection Procedure 2: Power Supply Circuit System: 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
• MB991970: ABS Check Harness

1. STEP 1. Measure the voltage at ABS-ECU connector A-02. 
   1. Disconnect the connector A-02, and connect special tool ABS Check Harness (MB991970) to the wiring harness-side connector.
      NOTE: Do not connect special tool ABS Check Harness (MB991970) to the ABS-ECU.
   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between terminal 20 and ground. It should measure approximately 12 volts (battery positive voltage).

   Q: Is battery positive voltage (approximately 12 volts) present? 

   YES:  Go to  Step 3.

   NO:  Go to Step 2.

   Fig 1: Measuring Voltage ABS-ECU Connector A-02

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Check ABS-ECU connector A-02, junction block connectors C-214, C-215 and ignition switch connector C-308 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
   • ABS-ECU connector A-02
     Fig 2: Checking ABS-ECU Connector A-02

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   • Junction block connectors C-214 and C-215
     Fig 3: Identifying Connector C-214,C-215

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   • Ignition switch connector C-308

   Q: Are the connectors and terminals in good condition? 

   YES:  An open or short circuit may be present in the power supply line to the ABS-ECU. Repair the wiring harness between ABS-ECU connector A-02 terminal 20 and ignition switch connector C-308 terminal 4. Then go to  Step 8.

   NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Then go to  Step 8.

   Fig 4: Identifying Connector C-308

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Measure the resistance at ABS-ECU connector A-02. 
   1. Disconnect the connector A-02, and connect special tool ABS Check Harness (MB991970) to the wiring harness-side connector.
      NOTE: Do not connect special tool ABS Check Harness (MB991970) to the ABS-ECU.
   2. Measure the resistance between terminal 2, 18 and ground. It should be 2 ohms or less.

   Q: Is the measured resistance 2 ohms or less? 

   YES:  Go to  Step 5.

   NO:  Go to Step 4.

   Fig 5: Measuring Resistance ABS-ECU Connector A-02

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check ABS-ECU connector A-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ABS-ECU connector A-02 damaged? 

   YES:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Then go to  Step 8.

   NO:  An open circuit may be present in the ground circuit. Repair the wiring harness between ABS-ECU connector A-02 terminals 2, 18 and the body ground. Then go to  Step 8.

   Fig 6: Checking ABS-ECU Connector A-02

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. Check the battery. 

   Check the battery (Refer to BATTERY TEST ).

   Q: Is the battery in good condition? 

   YES:  Go to Step 6.

   NO:  Charge or replace the battery. Then go to  Step 8.

6. STEP 6. Check the charging system. 

   Check the charging system (Refer to CHARGING SYSTEM DIAGNOSIS ).

   Q: Is the charging system in good condition? 

   YES:  Go to Step 7.

   NO:  Repair or replace the charging system component(s). Then go to  Step 8.

7. STEP 7. Retest the system. 

   Q: Can the ABS-ECU communicate with the scan tool (M.U.T.-III Sub Assembly)? 

   YES:  It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .

   NO:  Replace the ABS-ECU. Then go to Step 8.

8. STEP 8. Retest the system. 

   Q: Can the ABS-ECU communicate with the scan tool (M.U.T.-III Sub Assembly)? 

   YES:  The procedure is complete.

   NO:  Go to  Step 1.