U0435

DTC U0251: AWC time-out error (Local CAN)
DTC U0440: AWC communication error in AWC (Local CAN)
DTC U0435: AWC signal abnormality (Local CAN)













CAUTION:

- If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines Initial Inspection and Diagnostic Overview ).
- Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASC-ECU) is replaced, always perform the calibration of steering wheel sensor, G and yaw rate sensor, brake fluid pressure sensor, cut valve, and inlet valve (Refer to G and Yaw Rate Sensor Calibration , Testing and Inspection , Master Cylinder Brake Fluid Pressure Sensor Calibration , and Testing and Inspection ).

CIRCUIT OPERATION

AWC-ECU outputs the signal to ASC-ECU via the special CAN bus lines (Local CAN).

DTC SET CONDITIONS

These diagnostic trouble codes will be set under the cases below.

DTC U0251

- Signals sent from AWC-ECU to ASC-ECU cannot be received for a specified period.

DTC U0440

- Signals sent from AWC-ECU to ASC-ECU have an error.

DTC U0435

- A brake control request of outside the specified range is output by AWC-ECU.

PROBABLE CAUSES

- Wiring harness or connector failure in special CAN bus lines (Local CAN) between ASC-ECU and AWC-ECU
- AWC-ECU malfunction
- ASC-ECU malfunction

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 lines.

Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 3.
NO Repair the CAN bus lines CAN Bus Diagnostics Chart).
After repairing the CAN bus line, go to Step 2.
STEP 2. DTC recheck after repairing the CAN bus line

Q. Is DTC U0251, U0440 or U0435 set?

YES Go to Step 3.
NO This diagnosis is complete.
STEP 3. Diagnostic trouble code check of other system using scan tool MB991958

Using scan tool MB991958, check if a diagnostic trouble code is set in AWC-ECU.

Q. Is other DTC set?

YES Troubleshoot the relevant diagnostic trouble code, and then go to Step 8.
NO Go to Step 4.
STEP 4. Connector check: A-05 ASC-ECU connector, C-46 AWC-ECU connector, C-47 intermediate connector

Q. Is the check result normal?

YES Go to Step 5.
NO Repair the connector, and then go to Step 8.
STEP 5. Wiring harness check between A-05 ASC-ECU connector terminal No. 18 and C-46 AWC-ECU connector terminal No. 9, between A-05 ASC-ECU connector terminal No. 19 and C-46 AWC-ECU connector terminal No. 10

- Open or short circuit check of communication circuit

Q. Is the check result normal?

YES Go to Step 6.
NO Repair the wiring harness, and then go to Step 8.
STEP 6. Check whether the DTC is reset.

Q. Are DTC U0251, U0440, and U0435 set?

YES Replace the AWC-ECU Active Center Differential (ACD)).
Then go to Step 7.
NO Intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 7. Check whether the DTC is reset.

Erase the DTCs.

Q. Is DTC U0251, U0440 or U0435 set?

YES Replace the hydraulic unit (integrated with ASC-ECU) (Refer to Service and Repair). Then go to Step 8.
NO The procedure is complete.
STEP 8. Check whether the DTC is reset.

Erase the DTCs.

Q. Is DTC U0251, U0440 or U0435 set?

YES Return to Step 1.
NO The procedure is complete.