SRS-ECU

DTC U0168: KOS-ECU or 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 or WCM cannot be received, the SRS-ECU sets the DTC U0168.

DTC SET CONDITION
Because of the CAN-B bus circuit malfunction, if SRS-ECU becomes unable to perform the normal data transmission, SRS-ECU determines that an abnormality is present.

TROUBLESHOOTING HINTS
- Malfunction of CAN bus line may be defective.
- Malfunction of the KOS-ECU may be defective.
- Malfunction of the WCM may be defective.
- Malfunction of SRS-ECU 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 or WCM diagnostic trouble code

Check again if the DTC is set to the KOS-ECU or WCM.

Q: Is the DTC set?

YES : Diagnose the KOS or WCM. Then go Step 4.

NO : Go to Step 3.

STEP 3. Using scan tool MB991958, read diagnostic trouble code No. U0168 for other system.

Check if the DTC U0168 is set in ETACS-ECU, occupant classification-ECU, combination meter, A/C-ECU, hands free module, CAN box unit, radio and CD player, satellite radio tuner.

Q: Is the DTC set?

YES : Replace the KOS - ECU.

NO : Go to Step 4.

STEP 4. Recheck for diagnostic trouble code.

Check again if the DTC is set to the SRS-ECU.
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 SRS-ECU.

NO : There is an intermittent malfunction such as poor engaged connector(s) or open circuit.