INSPECTION PROCEDURE 1: Throttle Valve will not Fully Open or Close: Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (MUT-III Sub Assembly)
  • MB991824: Vehicle Communication Interface (V.C.I.)
  • MB991827: MUT-III USB Cable
  • MB991910: MUT-III Main Harness A

1. STEP 1. Using scan tool MB991958, read the diagnostic trouble code (DTC). 
   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. Ensure that the ignition switch is at the "LOCK" (OFF) position.
   2. Start up the personal computer.
   3. Connect special tool MB991827 to special tool MB991824 and the personal computer.
   4. Connect special tool MB991910 to special tool MB991824.
   5. Connect special tool MB991910 to the data link connector.
   6. Turn the power switch of special tool MB991824 to the "ON" position.
      NOTE: When special tool MB991824 is energized, special tool MB991824 indicator light will be illuminated in a green color.
   7. Start the MUT-III system on the personal computer.
   8. Turn the ignition switch to the "ON" position.
   9. Check for MFI system diagnostic trouble code. Refer to MFI Diagnosis - DIAGNOSTIC FUNCTION - (HOW TO READ AND ERASE DIAGNOSTIC TROUBLE CODE for < 2.4L engine >) or (HOW TO READ AND ERASE DIAGNOSTIC TROUBLE CODE for < 3.8L engine >).
   10. Turn the ignition switch to the "LOCK" (OFF) position, and then remove scan tool MB991958 in the reverse order of installation.
       Fig 1: Connecting Scan Tool To Data Link Connector

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

   Q: Is any DTC set? 

   YES :  Repair MFI system. Refer to MFI Diagnosis - (DIAGNOSTIC TROUBLE CODE CHART for < 2.4L engine >) or (DIAGNOSTIC TROUBLE CODE CHART for < 3.8L engine >). Then go to Step 2.

   NO :  Go to Step 2.

2. STEP 2. Retest the system. 

   Q: Does the throttle valve fully open and close? 

   YES :  The procedure is complete.

   NO :  Return to  Step 1.