INSPECTION PROCEDURE 8: Tachometer does not work (other meters work): 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, diagnose the CAN bus line. 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).
- Connect scan tool MB991958 to the data link connector.
- Turn the ignition switch to "ON" position.
- Diagnose the CAN bus line.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?
- YES : Go to Step 2.
- NO : Repair the CAN bus lines (Refer to CAN BUS DIAGNOSTIC CHART ).
- STEP 2. Using scan tool MB991958, read MFI system diagnostic trouble code.
Check if the MFI system diagnostic trouble code is set.
- Turn the ignition switch to "ON" position.
- Diagnose the CAN bus line.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
- YES : Refer to DIAGNOSTIC TROUBLE CODE CHART <2.4 L engine> or DIAGNOSTIC TROUBLE CODE CHART <3.8 L engine>.
- NO : Go to Step 3.
- STEP 3. Using scan tool MB991958, check data list.
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to the data reading mode.
- Item 05: Tachometer
- Tachometer displayed value and M.U.T.-III displayed value agree with each other.
- Item 05: Tachometer
- 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 COPE WITH INTERMITTENT MALFUNCTION .
- NO : Go to Step 4.
- STEP 4. Using scan tool MB991958, check actuator test.
- Turn the ignition switch to the "ON" position.
- Set scan tool MB991958 to the actuator test mode.
- Item 4: Tachometer: 0 r/min
- The tachometer displays 0 r/min.
- Item 5: Tachometer: 2,000 r/min
- The tachometer displays 2,000 r/min.
- Item 6: Tachometer: 5,000 r/min
- The tachometer displays 5,000 r/min.
- Item 4: Tachometer: 0 r/min
- 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.
- 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 COPE WITH INTERMITTENT MALFUNCTION ).
- NO : Replace the combination meter.