INSPECTION PROCEDURE 8: Tachometer does not Work: Diagnosis

Required Special Tools:

MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Diagnose the CAN bus line.
Q: Is the check result satisfactory?

YES: Go to Step 2.

NO: Repair the CAN bus lines (Refer to CAN BUS DIAGNOSTIC CHART ). On completion, go to Step 3.

Fig 1: Connecting Scan Tool To Data Link Connector
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 2. Using scan tool MB991958, read MFI system diagnostic trouble code.
Check if the MFI system DTC is set.

Q: Is the DTC set?

YES: Diagnose the MFI system (Refer to DIAGNOSTIC TROUBLE CODE CHART < 2.4L ENGINE > or DIAGNOSTIC TROUBLE CODE CHART < 3.8L ENGINE >). On completion, go to Step 5.

NO: Go to Step 3.
STEP 3. Using scan tool MB991958, check data list.
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.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the data reading mode.
  - Item 87: Tachometer
    - The voltage should equal battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result normally?

YES: It can be assumed that this malfunction is intermittent. Refer to "How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS " .

NO: Go to Step 4.

Fig 2: Connecting Scan Tool To Data Link Connector
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 4. Using scan tool MB991958, check actuator test.
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.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the actuator test mode.
  - Item 84: Tachometer: 0 r/min
    - The tachometer displays 0 r/min.
  - Item 85: Tachometer: 2000 r/min
    - The tachometer displays 2,000 r/min.
  - Item 86: Tachometer: 5000 r/min
    - The tachometer displays 5,000 r/min.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result normally?

YES: Go to Step 5.

NO: Replace the combination meter.

Fig 3: Connecting Scan Tool To Data Link Connector
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 5. Retest the system.
Check that the tachometer works normally.

Q: Is the check result satisfactory?

YES: The procedure is complete. (If no malfunctions are found in all steps, an intermittent malfunction is suspected. Refer to "How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS " ).

NO: Replace the combination meter.