Diagnostic Procedure

STEP 1. Using scan tool MB991958, read the MFI system 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. Connect scan tool MB991958 to the data link connector (Refer to DIAGNOSTIC FUNCTION ).
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to check for MFI system DTC (Refer to DIAGNOSTIC FUNCTION ).
  Q: Is any DTC set?
  1. YES: Repair the MFI system (Refer to DIAGNOSTIC TROUBLE CODE CHART ). Then go to Step 2.
  2. NO: Go to Step 2.
STEP 2. Check the symptom.
Q: Does the throttle valve fully open and close?
1. YES: The procedure is complete.
2. NO: Return to Step 1.