Wireless Control Module (WCM)

DTC U0155: Combination meter CAN time-out

CAUTION:

- If DTC 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

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) Reading and Clearing Diagnostic Trouble Codes".
(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 CAN Bus Diagnostics Chart).

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?

YES Troubleshoot the combination meter Combination Meter).
NO Go to Step 3.
STEP 3. Using scan tool MB991958, read the A/C-ECU diagnostic trouble code.

Check if the DTC U0155 is set to the A/C-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 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?

YES Replace the combination meter.
NO 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 How to Cope With Intermittent Malfunctions).
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?

YES Replace WCM and register the ID codes (Refer to ID registration procedure manual - ID codes registration judgement table).
NO 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 How to Cope With Intermittent Malfunctions).