MMCS CAN Time-Out

DTC U0245: MMCS CAN Time-out

CAUTION:

- If the DTC U0245 is set, diagnose the CAN bus lines.
- When replacing the ECU, always check that the SRS circuit is normal.

DIAGNOSTIC FUNCTION

If the signal from ETACS-ECU cannot be received, the SRS-ECU sets the diagnosis code No.
U0245.

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
- Malfunction of SRS-ECU
- Malfunction of the audio visual navigation unit

DIAGNOSIS

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 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 audio diagnostic trouble code

Check if the DTC is set to the audio.

Q. Is the DTC set?

YES Diagnose the MMCS. Then go to Step 4.
NO Go to Step 3.
STEP 3. Using scan tool MB991958, read diagnostic trouble code No.
U0245 for other system.

Check if the DTC U0245 is set in ETACS-ECU, occupant classification-ECU, combination meter, A/C-ECU, KOS-ECU or WCM, radio and CD player, satellite radio tuner, OSS-ECU.

Q. Is the DTC set?

YES Replace the MMCS Service and Repair).
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 How to Cope With Intermittent Malfunctions).