U113C

DTC U113C: Wheel speed sensor data error

CAUTION:

- If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, always diagnose the CAN bus lines.

- Before replacing the ECU, ensure that the communication circuit is normal.

OPERATION

AWD-ECU receives the data (such as ABS sensor signal, ABS operation signal) via the CAN bus lines. If it cannot receive such data, it interrupts the system.

DTC SET CONDITIONS

If the following conditions are met when the system is activated, AWD-ECU gradually switches the control from AWD to FWD, flashes the AWD/LOCK indicators alternately, and sets the DTC U113C.

- IG1 voltage: 8 V or more

- ABS signal (such as wheel speed signal) cannot be received.

- DTC U0121 ABS CAN timeout is not detected.

TROUBLESHOOTING HINTS

Current trouble

- Wiring harness or connector failure between ABS/ASC-ECU and the stoplight switch

- Malfunction of the wheel speed sensor

- Malfunction of the stoplight switch

- ABS/ASC-ECU malfunction

- AWD-ECU malfunction
Past trouble

- Refer to How to Use Troubleshooting - How to Treat Past Trouble How to Treat Past Trouble for proceeding the diagnostics.
Diagnose mainly wiring harness or connector failure in the CAN bus lines between ABS/ASC-ECU and each wheel speed sensor, or between ABS/ASC-ECU and the stoplight switch.

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface

- MB991827: M.U.T.-III USB Cable

- MB991910: M.U.T.-III Main Harness A

STEP 1. Scan tool MB991958 CAN bus diagnostics

Use scan tool MB991958 to diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 2.
NO Repair the CAN bus line CAN Bus Diagnostics Chart). Then go to Step 2.
STEP 2. Scan tool MB991958 data list

Check the following data list (Refer to Data List Reference Table).

- Item 07: CAN system (ABS/ASC)

- Item 16: FL wheel speed sensor

- Item 17: FR wheel speed sensor

- Item 18: RL wheel speed sensor

- Item 19: RR wheel speed sensor

Q. Is the check result normal?

YES Go to Step 3.
NO Troubleshoot the ABS system Anti-Lock Braking System (ABS)[Vehicles with ABS]), the ASC system
Active Stability Control System (ASC) [Vehicles with ASC]). Then go to Step 3.
STEP 3. Check whether the DTC is reset.

(1)Erase the DTC.

(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.

(3)Check if the DTC is set.

Q. Is the DTC U113C set?

YES Replace AWD-ECU (Refer to Electronic Control AWD). Then go to Step 4 .
NO A poor connection, open circuit or other intermittent malfunction in the CAN bus lines between ABS/ASC-ECU and each wheel speed sensor, or between ABS/ASC-ECU and the stoplight switch is suspected. How to Cope With Intermittent Malfunctions).
STEP 4. Check whether the DTC is reset.

Q. Is the DTC U113C set?

YES Diagnose again from Step 1.
NO The procedure is complete.