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.

JUDGEMENT CRITERIA

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

(1)

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.

Connect scan tool MB991958. Refer to "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?

Go to Step 2.

Repair the CAN bus line (Refer to GROUP 54C, Diagnosis

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?

	Diagnose the KOS or WCM. Then go to Step3.

	Go to Step 3.

STEP 3. 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?

	Replace the SRS-ECU (Refer to ).

	There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to use Troubleshooting/inspection Service Points ).