Radio and CD Player

DTC U0168: WCM CAN Timeout

CAUTION:
- If DTC U0168 is set, be sure to diagnose the CAN bus line.
- When replacing the ECU, always check that the communication circuit is normal.

DIAGNOSTIC FUNCTION
If the signal from KOS-ECU [vehicles with KOS] or WCM [vehicles with WCM] cannot be received, the radio and CD player sets DTC U0168.

JUDGMENT CRITERIA
With the ignition switch in the ON position, system voltage between 10 - 16 V (data from ETACS-ECU), power supply fuse(IOD fuse) is OK, or odometer value is 80.5 km (50 miles) or more, and the communication with KOS-ECU [vehicles with KOS] or WCM [vehicles with WCM] cannot be established for 2,500 ms or more, the radio and CD player determines that a problem has occurred.

TROUBLESHOOTING HINTS
- Malfunction of CAN bus line may be defective.
- Malfunction of the KOS-ECU may be defective. [vehicles with KOS]
- Malfunction of the WCM may be defective. [vehicles with WCM]
- Malfunction of radio and CD player may be defective.

DIAGNOSIS

Required Special Tools:
- 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, 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.







1. Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.

NO : Repair the CAN bus line.

STEP 2. Using scan tool MB991958, read the KOS-ECU [vehicles with KOS] or WCM [vehicles with WCM] diagnostic trouble code.

Check again if the DTC is set to the KOS-ECU [vehicles with KOS] or WCM [vehicles with WCM].

Q: Is the DTC set?

YES : Troubleshoot the KOS or WCM (Refer to Diagnosis Diagnostic Trouble Code Descriptions [KOS] or Diagnosis Diagnostic Trouble Code Descriptions [WCM]).

NO : Go to Step 3.

STEP 3. Recheck for diagnostic trouble code.

Check again if the DTC is set to the radio and CD player
1. Erase the DTC.
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 : Replace the radio and CD player.

NO : The trouble can be an intermittent malfunction.