Inspection Procedure 8
INSPECTION PROCEDURE 8: Tachometer does not work (other meters work).
CIRCUIT OPERATION
The ECM [M/T] or PCM [A/T] sends ignition signal to the combination meter via CAN bus line.
TECHNICAL DESCRIPTION (COMMENT)
If only the tachometer does not operate, the ECM [M/T] or PCM [A/T] system may not be sending ignition signal, or the combination meter, the wiring harness or its connector may be defective.
TROUBLESHOOTING HINTS
- Malfunction of the combination meter
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
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.
(1)
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.
(2)Turn the ignition switch to "ON" position.
(3)Diagnose the CAN bus line.
(4)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 CAN Bus Diagnostics Chart).
STEP 2. Using scan tool MB991958, read MFI system diagnostic trouble code.
Check if the MFI system diagnostic trouble code is set.
(1)Turn the ignition switch to "ON" position.
(2)Diagnose the CAN bus line.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is the DTC set?
YES Multiport Fuel Injection (MFI) [2.4 L engine] or MFI Diagnosis - Diagnostic Trouble Code Chart Multiport Fuel Injection (MFI) [3.8 L engine].
NO Go to Step 3.
STEP 3. Using scan tool MB991958, check data list.
(1)Turn the ignition switch to the "ON" position.
(2)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.
(3)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. How to Cope With Intermittent Malfunctions.
NO Go to Step 4.
STEP 4. Using scan tool MB991958, check actuator test.
(1)Turn the ignition switch to the "ON" position.
(2)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.
(3)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. How to Cope With Intermittent Malfunctions).
NO Replace the combination meter.