DTC 23: Powertrain Control Module (PCM) and Its Related Components: Diagnosis

Required Special Tools:

MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, read the MFI system diagnostic trouble code.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector. (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ).
2. Turn the ignition switch to the "ON" position.
3. Check for MFI system diagnostic trouble code. (Refer to DIAGNOSTIC TROUBLE CODE CHART ).
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.
  Q: Is any DTC set?
  1. YES: Diagnose the MFI system. (Refer to DIAGNOSTIC TROUBLE CODE CHART ). Then go to Step 4.
  2. NO: Go to Step 2.
    
    Fig 1: Identifying Scan Tool MB991958 Connection With Data Link Connector
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 2. Using scan tool MB991958, read the A/T system diagnostic trouble code.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector. (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ).
2. Turn the ignition switch to the "ON" position.
3. Check for A/T system diagnostic trouble code. (Refer to HOW TO READ AND ERASE DIAGNOSTIC TROUBLE CODE ).
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.
  Q: Is any DTC set?
  1. YES: Diagnose the A/T system. (Refer to DIAGNOSTIC TROUBLE CODE CHART ). Then go to Step 4.
  2. NO: Go to Step 3.
    
    Fig 2: Identifying Scan Tool MB991958 Connection With Data Link Connector
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 3. Using scan tool MB991958, read the auto-cruise control system diagnostic trouble code.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector. (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ).
2. Turn the ignition switch to the "ON" position.
3. Use scan tool MB991958 to read the auto-cruise control system diagnostic trouble codes. (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ).
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.
  Q: Is DTC 23 set?
  1. YES: Replace the PCM. When the PCM is replaced, register the encrypted code. Refer to ENCRYPTED CODE REGISTRATION CRITERIA TABLE . Then go to Step 4.
  2. NO: It can be assumed that this malfunction is intermittent. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
    
    Fig 3: Identifying Scan Tool MB991958 Connection With Data Link Connector
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 4. Using scan tool MB991958, read the auto-cruise control system diagnostic trouble code.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector. (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ).
2. Turn the ignition switch to the "ON" position.
3. Use scan tool MB991958 to read the auto-cruise control system diagnostic trouble codes. (Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ).
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.
  Q: Is DTC 23 set?
  1. YES: Return to Step 1.
  2. NO: The procedure is complete.
    
    Fig 4: Identifying Scan Tool MB991958 Connection With Data Link Connector
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.