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DTC 54: A/T Control Relay System: Diagnosis

Required Special Tool: 

  1. MB991502: Scan Tool (MUT-II)
  1. STEP 1. Using scan tool MB991502, check data list item 54: A/T Control Relay Output Voltage. 
    CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
    1. Connect scan tool MB991502 to the data link connector.
      Fig 1: Connecting Scan Tool To Data Link Connector
      G01876669Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Set scan tool MB991502 to data reading mode for item 54, A/T Control Relay Output Voltage.
      • The voltage should equal battery positive voltage.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage equal battery positive voltage? 

    1. YES:  It can be assumed that this malfunction is intermittent.
    2. NO:  Go to Step 2.
  2. STEP 2. Check the A/T control relay. 
    1. Remove the A/T control relay from the engine component relay box connector B-11X.
      Fig 2: Removing A/T Control From Relay Box Connector B-11X
      G01876670Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Using jumper wires, connect terminal 3 to the positive battery terminal, and terminal 2 to the negative battery terminal.
      Fig 3: Using Jumper Wires To Connect Terminals
      G01876671Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    3. Measure the resistance between terminals 1 and 4 of the A/T control relay.
    • The resistance should measure less than 2 ohms.
    • Disconnect the jumper wires. The resistance between terminals 1 and 4 should measure over limits (open circuit).

    Q: Does the resistance measure less than 2 ohms when the relay is energized, and open circuit when the relay is de-energized? 

    1. YES:  Go to Step 3.
    2. NO:  Replace the A/T control relay.
  3. STEP 3. Check A/T control relay socket B-11X in the engine compartment relay box for loose, corroded or damaged terminals, or terminals pushed back in the socket. 
    Fig 4: Checking A/T Control Relay Socket B-11X
    G01876672Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the relay connector in good condition? 

    1. YES:  Go to Step 4.
    2. NO:  Repair or replace the damaged components.
  4. STEP 4. Measure the supply voltage at A/T control relay connector B-11X in the engine component relay box. 
    1. Disconnect the A/T control relay.
      Fig 5: Disconnecting A/T Control Relay Connector B-11X
      G01876673Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Measure the voltage between terminal 1 and ground.
    • The measured voltage should equal battery positive voltage.
    Fig 6: Measuring Voltage Between Terminal 1 & Ground
    G01876674Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the measured voltage equal to battery positive voltage? 

    1. YES:  Go to  Step 7 .
    2. NO:  Go to Step 5.
  5. STEP 5. Check intermediate connector A-13 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 7: Checking Intermediate Connector A-13
    G01876675Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 6.
    2. NO:  Repair or replace the damaged components.
  6. STEP 6. Check the harness for open circuit or short circuit to ground between A/T control relay connector B-11X terminal 1 in the engine component relay box and battery. 
    Fig 8: Checking A/T Control Relay Connector B-11X For Open Or Short Circuit To Ground
    G01876676Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to  Step 18 .
    2. NO:  Repair or replace the harness wire.
  7. STEP 7. Measure the supply voltage at A/T control relay connector B-11X in the engine component relay box. 
    1. Disconnect the A/T control relay.
      Fig 9: Disconnecting A/T Control Relay Connector B-11X
      G01876677Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 2 and ground.
      • The measured voltage should equal battery positive voltage.
      Fig 10: Measuring Voltage Between Terminal 2 & Ground
      G01876678Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage equal to battery positive voltage? 

    1. YES:  Go to  Step 10 .
    2. NO:  Go to Step 8.
  8. STEP 8. Check intermediate connector C-123 and junction block connector C-210 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 11: Checking Intermediate Connector C-123
    G01876679Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 12: Checking Junction Block Connector C-210
    G01876680Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connectors in good condition? 

    1. YES:  Go to Step 9.
    2. NO:  Repair or replace the damaged components. .
  9. STEP 9. Check the harness for open circuit or short circuit to ground between A/T control relay connector B-11X terminal 2 in the engine component relay box and junction block connector C-210 terminal 12. 
    Fig 13: Checking A/T Control Relay Connector B-11X For Open Or Short Circuit To Ground
    G01876681Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 14: Checking Junction Block Connector C-210 For Open Or Short Circuit To Ground
    G01876682Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to  Step 18 .
    2. NO:  Repair or replace the harness wire.
  10. STEP 10. Measure the supply voltage at PCM connector C-118 by backprobing. 
    1. Do not disconnect connector C-118.
      Fig 15: Identifying PCM Connector C-118
      G01876683Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Measure the voltage between terminal 50 and ground by backprobing.
      • The measured voltage should equal battery positive voltage.
      Fig 16: Measuring Voltage Between Terminal 50 & Ground
      G01876684Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    3. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Does the measured voltage equal battery positive voltage? 

    1. YES:  Go to  Step 14 .
    2. NO:  Go to Step 11.
  11. STEP 11. Check PCM connector C-118 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 17: Checking PCM Connector C-118
    G01876685Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 12.
    2. NO:  Repair or replace the damaged components. .
  12. STEP 12. Check harness for open circuit or damage between A/T control relay connector B-11X terminal 3 in the engine component relay box and PCM connector C-118 terminal 50. 
    Fig 18: Checking A/T Control Relay Connector B-11X For Open Circuit Or Damage
    G01876686Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 19: Checking PCM Connector C-118 For Open Circuit Or Damage
    G01876687Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 13.
    2. NO:  Repair or replace the harness wire.
  13. STEP 13. Check harness for short circuit to ground between A/T control relay connector B-11X terminal 3 in the engine component relay box and PCM connector C-118 terminal 50. 
    Fig 20: Checking A/T Control Relay Connector B-11X For Short Circuit To Ground
    G01876688Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 21: Checking PCM Connector C-118 For Short Circuit To Ground
    G01876689Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 14.
    2. NO:  Repair or replace the harness wire.
  14. STEP 14. Measure the A/T control relay output voltage at PCM connector C-116 by backprobing. 
    1. Do not disconnect connector C-116.
      Fig 22: Identifying PCM Connector C-116
      G01876690Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 77 and ground by backprobing.
      • The measured voltage should equal battery positive voltage.
      Fig 23: Measuring Voltage Between Terminal 77 & Ground
      G01876691Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Measure the voltage between terminal 89 and ground by backprobing.
      • The measured voltage should equal battery positive voltage.
      Fig 24: Measuring Voltage Between Terminal 89 & Ground
      G01876692Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage equal to battery positive voltage between terminal 77 and ground, and between terminal 89 and ground? 

    1. YES:  Go to  Step 18 .
    2. NO:  Go to Step 15.
  15. STEP 15. Check PCM connector C-116 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 25: Checking PCM Connector C-116
    G01876693Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 16.
    2. NO:  Repair or replace the damaged components.
  16. STEP 16. Check harness for open circuit or damage between A/T control relay connector B-11X (terminal 4) in the engine component relay box and PCM connector C-116 (terminals 77 and 89). 
    Fig 26: Checking A/T Control Relay Connector B-11X For Open Circuit Or Damage
    G01876694Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 27: Checking PCM Connector C-116 For Open Circuit Or Damage
    G01876695Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 17.
    2. NO:  Repair or replace the harness wire.
  17. STEP 17. Check harness for short circuit to ground between A/T control relay connector B-11X (terminal 4) in the engine component relay box and PCM connector C-116 (terminals 77 and 89). 
    Fig 28: Checking A/T Control Relay Connector B-11X For Short Circuit To Ground
    G01876696Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 29: Checking PCM Connector C-116 For Short Circuit To Ground
    G01876697Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 18.
    2. NO:  Repair or replace the harness wire.
  18. STEP 18. Using scan tool MB991502, check data list item 54: A/T control relay output voltage. 
    CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
    1. Connect scan tool MB991502 to the data link connector.
      Fig 30: Connecting Scan Tool To Data Link Connector
      G01876698Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Set scan tool MB991502 to data reading mode for item 54, A/T Control Relay Output Voltage.
      • The voltage should equal battery positive voltage.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage equal battery positive voltage? 

    1. YES:  It can be that this malfunction is intermittent.
    2. NO:  Replace the PCM.
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