Inspection Procedure 1

Inspection Procedure 1: Power supply circuit check.


















TECHNICAL DESCRIPTION (COMMENT)

If the odometer and tripmeter do not display or all the meter needles do not move, the power supply to the combination meter, or the combination meter itself may have a problem.

TROUBLESHOOTING HINTS

- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The combination meter may be defective

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles 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, read the combination meter diagnostic trouble code.

Check if DTC is set to the combination meter.





(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. Refer to "How to connect the Scan Tool (M.U.T.-III) Harness Connector Inspection."
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Check if DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Troubleshoot the combination meter (Refer to Combination Meter).

NO Go to Step 2.

STEP 2. Check combination meter connector C-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is combination meter connector C-04 in good condition?

YES Go to Step 3.
NO Repair the defective connector.
STEP 3. Check the battery power supply circuit to the combination meter. Measure the voltage at combination meter connector C-04.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Turn the ignition switch to the LOCK (OFF) position.





(3)Measure the voltage between terminals 1 and ground.

- The voltage should measure approximately 12 volts (battery positive voltage).

Q. Is the measured voltage approximately 12 volts (battery positive voltage)?

YES Go to Step 5.

NO Go to Step 4.

STEP 4. Check the wiring harness between combination meter connector C-04 (terminal 1) and the fusible link (36).

- Check the power supply line (battery supply) for open circuit and short circuit.

NOTE:
Also check ETACS-ECU connectors C-307 and C-317 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If ETACS-ECU connectors C-307 and C-317 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between combination meter connector C-04 (terminal 1) and the fusible link (36) in good condition?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Repair the wiring harness.
STEP 5. Check the battery power supply circuit to the combination meter. Measure the voltage at combination meter connector C-04.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Turn the ignition switch to the ON position.





(3)Measure the voltage between terminals 2 and ground.

- The voltage should measure approximately 12 volts (battery positive voltage).

Q. Is the measured voltage approximately 12 volts (battery positive voltage)?

YES Go to Step 8.

NO Go to Step 6.

STEP 6. Using scan tool MB991958, check data list.

Check the input signal from the ignition switch (IG1) in the ETACS-ECU.

(1)Check the ETACS data list.

- Turn the ignition switch to the "ON" position.





(2)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Do the scan tool MB991958 display the item "IG voltage" is normal condition?

YES Go to Step 7.
NO : Troubleshoot the ETACS-ECU. Refer to Inspection Procedure 2 "The ignition switch
(IG1) signal is not received Inspection Procedure 2."
STEP 7. Check the wiring harness between combination meter connector C-04 (terminal 2) and the fusible link (34).

- Check the power supply line (battery supply) for open circuit and short circuit.

NOTE:
Also check ETACS-ECU connectors C-309 and C-317 and joint connector C-101 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If ETACS-ECU connector C-309 or C-317 or joint connector C-101 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between combination meter connector C-04 (terminal 2) and the fusible link (34) in good condition?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Repair the wiring harness.
STEP 8. Check the ground circuit to the combination meter. Test at combination meter connector C-04.

(1)Disconnect combination meter connector C-04 and measure the resistance available at the wiring harness side of the connector.





(2)Measure the resistance value between terminal 13 and ground.

- The resistance should be 2 ohms or less.

Q. Is the measured resistance 2 ohms or less?

YES Go to Step 10.

NO Go to Step 9.

STEP 9. Check the wiring harness between combination meter connector C-04 (terminal 13) and ground.

- Check the ground wire for open circuit.

Q. Is the wiring harness between combination meter connector C-04 (terminal 13) and ground in good condition?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Repair the wiring harness.
STEP 10. Retest the system.

Check that the combination meter works normally.

Q. Is the check result satisfactory?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Replace the combination meter.