Hands-Free Cellular Phone System

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 hands free module sets DTC U0168.

PROBABLE CAUSES
- The CAN bus line may be defective.
- The KOS-ECU may be defective. [vehicles with KOS]
- The WCM may be defective. [vehicles with WCM]
- The hands free module 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)." Scan Tool Connecting
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 (Refer to Controller Area Network, Diagnosis).

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 Keyless Operation System, Diagnosis [KOS] or Wireless Control Module, Diagnosis [WCM]).

NO : Go to Step 3.

STEP 3. Recheck for diagnostic trouble code.

Check again if the DTC is set to the hands free module.

1. Erase the DTC.
2. Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
3. Check if DTC is set.

Q : Is the DTC set?

YES : Replace the hands free module.

NO : The trouble can be an intermittent malfunction (Refer to General (Body and Chassis) -How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).