Hands Free Cellular Phone System
DTC U0168: WCM/KOS CAN TimeoutCAUTION:
- 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.
TECHNICAL DESCRIPTION (COMMENT)
If the signal from KOS-ECU [vehicles with KOS] or WCM [vehicles with WCM] cannot be received, the hands free module sets DTC U0168.
TROUBLESHOOTING HINTS
- 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)." 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. Using scan tool MB991958, read the diagnostic trouble code.
Check if the DTC U0168 is set to the ETACS-ECU.
Q: Is the DTC set?
YES : Go to Step 4.
NO : Go to Step 5.
STEP 4. 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.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Replace the WCM or KOS-ECU.
NO : The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the WCM or KOS-ECU and the hands free module.
STEP 5. 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.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Replace the hands free module.
NO : The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the WCM or KOS-ECU and the hands free module.