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INSPECTION PROCEDURE 1: Communication with Scan Tool MB991958 is Impossible.: Diagnosis

Required Special Tools: 

  1. STEP 1. Using scan toll MB991958, read the MFI system diagnostic trouble code. 
    CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool.

    Use scan tool MB991958 to confirm the MFI system DTC.

    1. Connect scan tool MB991958 to the data link connector.
      Fig 1: Connecting Scan Tool MB991958 To Data Link Connector
      G02445597Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch "ON" to position.
    3. Read the MFI system diagnosis code.

    Q: Can scan tool MB991958 communicate with the MFI system? Is an MFI system DTC other than P0513 output? 

    1. YES:  Go to Step 2.
    2. NO:  Refer to DIAGNOSTIC TROUBLE CODE CHART .
  2. STEP 2. Check the immobilizer-ECU power supply circuit by backprobing. 
    1. Do not disconnect immobilizer-ECU connector C-79
      Fig 2: Identifying Immobilizer-ECU Connector C-79
      G02445598Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 7 and ground by backprobing.
      • The measured value should be approximately 12 volts (battery positive voltage).
        Fig 3: Measuring Voltage Between Terminal 7 And Ground
        G02445599Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Does the measured voltage correspond with this range? 

    1. YES:  Go to  Step 5.
    2. NO:  Go to Step 3.
  3. STEP 3. Check immobilizer-ECU connector C-79 and MFI relay connector A-18X for damage. 
    Fig 4: Checking Immobilizer-ECU Connector C-79
    G02445600Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 5: Checking MFI Relay Connector A-18X
    G02445601Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are immobilizer-ECU connector C-79 and MFI relay connector A-18X damaged? 

    1. YES:  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION . Confirm that scan tool MB991958 communicates normally.
    2. NO:  Go to Step 4.
  4. STEP 4. Check the wiring harness between immobilizer-ECU connector C-79 (terminal 7) and MFI relay connector A-18X (terminal 4). 
    Fig 6: Checking Immobilizer-ECU Connector C-79
    G02445602Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 7: Checking MFI Relay Connector A-18X
    G02445603Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    NOTE: After checking intermediate connector C-28, check the wires. If intermediate connector C-28 is damaged, repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .
    Fig 8: Checking Intermediate Connector C-28 And Replace Wiring Harness
    G02445604Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the wiring harness between immobilizer-ECU connector C-79 (terminal 7)and MFI relay connector A-18X (terminal 4)damaged? 

    1. YES:  Replace the wiring harness. Confirm that scan tool MB991958 communicates normally.
    2. NO:  There is no action to be taken.
  5. STEP 5. Check the immobilizer-ECU ground circuit by backprobing. 
    1. Do not disconnect immobilizer-ECU connector C-79.
      Fig 9: Identifyng Immobilizer-ECU Connector C-79
      G02445605Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Measure the resistance between terminal 3 and ground by backprobing.
      • The measured value should be 2 ohm or less.
        Fig 10: Measuring Resistance Between Terminal 3 And Ground
        G02445606Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Does the measured resistance value correspond with this range? 

    1. YES:  Go to Step 6.
    2. NO:  Go to  Step 8.
  6. STEP 6. Check immobilizer-ECU connector C-79 for damage. 
    Fig 11: Checking Immobilizer-ECU Connector C-79
    G02445607Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is immobilizer-ECU connector C-79 in good condition? 

    1. YES:  Go to Step 7.
    2. NO:  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION . Confirm that scan tool MB991958 communicates normally.
  7. STEP 7. Check the wiring harness between immobilizer-ECU connector C-79 (terminal 3) and ground. 
    Fig 12: Checking Wiring Harness Between Immobilizer-ECU Connector C-79 And Ground
    G02445608Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the wiring harness between immobilizer-ECU connector C-79 (terminal 3) and ground damaged? 

    1. YES:  Repair the wiring harness. Confirm that scan tool MB991958 communicates normally.
    2. NO:  There is no action to be taken.
  8. STEP 8. Check the wiring harness between immobilizer-ECU connector C-79 (terminal 5) and ECM connector C-56 (terminal 51) <2.4L M/T>, C-62 (terminal 98) <3.0L M/T> or PCM connector C-61 (terminal 111) <2.4L A/T>, C-63 (terminal 111) <3.0L A/T>. 
    Fig 13: Checking Immobilizer-ECU Connector C-79 Wiring Harness
    G02445609Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 14: Checking ECM Connector C-56 Wiring Harness
    G02445610Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the wiring harness between immobilizer-ECU connector C-79 and ECM connector C-56 (terminal 51) <2.4L M/T>, C-62 (terminal 98) <3.0L M/T> or PCM connector C-61 (terminal 111) <2.4L A/T>, C-63 (terminal 111) <3.0L A/T> damaged? 

    1. YES:  Repair the wiring harness. Confirm that scan tool MB991958 communicates normally.
    2. NO:  Go to Step 9.
  9. STEP 9. Replace the immobilizer-ECU. 

    Q: Did the communication with MUT-II become possible after replacing the immobilizer-ECU? 

    1. YES:  Register the password (secret code) and encrypted code (Refer to ON-VEHICLE SERVICE  ). Confirm that scan tool MB991958 communicates normally.
    2. NO:  Go to Step 10.
  10. STEP 10. Recheck for malfunction 

    Q: Is a malfunction eliminated? 

    1. YES:  Go to Step 11.
    2. NO:  Replace the immobilizer-ECU.
  11. STEP 11. Replace the ECM < M/T > or PCM < A/T >. 

    Q: Did the communication with MUT-II become possible after replacing the Engine control module < M/T > or the power train control module < A/T >? 

    1. YES:  Register the password (secret code) and encrypted code (Refer to ON-VEHICLE SERVICE  ). Confirm that scan tool MB991958 communicates normally.
    2. NO:  Go to Step 12.
  12. STEP 12. Recheck for malfunction 

    Q: Is a malfunction eliminated? 

    1. YES:  The procedure is complete (If no malfunction are not found in all steps, an intermittent malfunction is suspected. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).
    2. NO:  Replace the ECM < M/T > or PCM < A/T >.
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