Inspection Procedure 6
INSPECTION PROCEDURE 6: Speedometer does not Work.
INSPECTION PROCEDURE 7: The Fuel Gauge Needle Moves Excessively.
CAUTION:
When the battery cable is disconnected or the combination meter is removed, the fuel gauge learned value will be erased. To let the display unit re-learn it, enter the vehicle speed (by driving the vehicle or entering simulated vehicle speed) and then stop the vehicle.
CIRCUIT OPERATION
The output shaft speed sensor sends vehicle signal to the combination meter via the powertrain control module and the CAN bus line.
TECHNICAL DESCRIPTION (COMMENT)
If only the speedometer does not operate, the powertrain control module system, the combination meter, the wiring harness or its connector may be defective. Furthermore, incorrect level of fuel is shown on the gauge, because the display unit can not learn the fuel gauge.
TROUBLESHOOTING HINTS
- Malfunction of the combination meter
- Malfunction of the powertrain control module
- 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: 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 CAN Bus Diagnostics Chart).
On completion, go to Step 5.
STEP 2. Using scan tool MB991958, read A/T diagnostic trouble code.
Check if an A/T system DTC is set.
Q. Is the DTC set?
YES Automatic Transmission. On completion, go to Step 5.
NO Go to Step 3.
STEP 3. Using scan tool MB991958, check data list.
(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 the "ON" position.
(3)Set scan tool MB991958 to the data reading mode.
- Item 80: Speedometer
- Vehicle speeds displayed on the speedometer and scan tool MB991958 are identical.
- Item 81: Speedometer (Target)
- Speed meter and scan tool MB991958 displayed values agree with each other voltage.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is the check result satisfactory?
YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.
NO Go to Step 4.
STEP 4. Check the speedometer
Use scan tool MB991958 to enter simulated vehicle speed.
(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to "ON" position.
(3)Select "Interactive Diagnosis" from the start-up screen.
(4)Select "System Select."
(5)Choose "Meter" from the "BODY" tab.
(6)Select "Simulated vehicle Speed Output."
OK: The speedometer shows that simulated vehicle speed.
Q. Is the check result satisfactory?
YES Go to Step 5.
NO Replace the combination meter, then go to Step 5.
STEP 5. Retest the system.
Check that the speedometer 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.