MMCS
DTC U0168: WCM/KOS CAN TimeoutCAUTION:
- If DTC U0168 is set, be sure to diagnose the CAN bus line.
- When replacing the CAN box unit, always check that the communication circuit is normal. (Check that the voltage is 10 V or more.)
DIAGNOSTIC FUNCTION
If the signal from KOS-ECU [vehicles with KOS] or WCM [vehicles with WCM] cannot be received, the CAN box unit 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 CAN box unit 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 CAN box unit 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 CAN box unit
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 CAN box unit.
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set to the CAN box unit
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 CAN box unit.
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 CAN box unit.