DTC U0155: Combination meter CAN timeout

caution

If the diagnostic trouble code U0155 is set, be sure to diagnose the CAN bus line.
When replacing the ECU, always check that the communication circuit is normal.

TROUBLE JUDGMENT

If no signal from the combination meter can be received, WCM sets DTC U0155.

TROUBLESHOOTING HINTS

Malfunction of CAN bus line
Combination meter malfunction
Malfunction of WCM

DIAGNOSIS

Required Special Tools:

MB991958: Scan Tool (M.U.T.-III Sub Assembly)

MB991824: Vehicle 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 combination meter diagnostic trouble code.

Check if DTC is set to the combination meter.

Q. Is the DTC set?

	Troubleshoot the combination meter. (Refer to GROUP 54A, Diagnosis .)

	Go to Step 3.

STEP 3. Using scan tool MB991958, read the A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C> diagnostic trouble code.

Check if the DTC U0155 is set to the A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C>.

Q. Is the DTC set?

	Go to Step 4.

	Go to Step 5.

STEP 4. Recheck for diagnostic trouble code.

Check again if the DTC is set to the WCM.

(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 combination meter.

	The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the combination meter and the WCM. (Refer to GROUP 00, How to Cope with Intermittent Malfunction )

STEP 5. Recheck for diagnostic trouble code.

Check again if the DTC is set to the WCM.

(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 WCM and register the ID codes. (Refer to .)

	The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the combination meter and the WCM. (Refer to GROUP 00, How to Cope with Intermittent Malfunction )