U1003

DTC U1003 G and yaw rate sensor bus-off













CAUTION:

- If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines CAN Bus Line Diagnostics Flow.
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- Do not drop or shock the G and yaw rate sensor.
- When the G and yaw rate sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to Active Stability Control System (ASC) ).
- When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor (Refer to Active Stability Control System (ASC) , Active Stability Control System (ASC) and Active Stability Control System (ASC) ).

OPERATION

The G and yaw rate sensor outputs the signal to ASC-ECU via the special CAN bus lines.

DTC SET CONDITIONS

This DTC is set when the communication error occurs in the exclusive CAN bus communication between the ASC-ECU and the G and yaw rate sensor.

PROBABLE CAUSES

- Wiring harness or connector failure for the special CAN bus lines between ASC-ECU and the G and yaw rate sensor
- Malfunction of the G and yaw rate sensor
- 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.

Use scan tool to 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.) On completion, go to Step 2.
STEP 2. DTC recheck after resetting CAN bus lines

Q. Is DTC U1003 set?

YES Go to Step 3.
NO The procedure is complete.
STEP 3. Connector check: A-51 ASC-ECU connector, C-137 G and yaw rate sensor connector

Q. Is the check result normal?

YES Go to Step 4.
NO Repair the connector, and then go to Step 7.
STEP 4. Wiring harness check between A-51 ASC-ECU connector terminal No.18 and C-137 G and yaw rate sensor connector terminal No.3 as well as between A-51 ASC-ECU connector terminal No.19 and C-137 G and yaw rate sensor connector terminal No.2

- Check the communication circuit for open and short circuit.

Q. Is the check result normal?

YES Go to Step 5.
NO Repair the wiring harness, and then go to Step 7.
STEP 5. DTC recheck

Erase the DTC.

Q. Is DTC U1003 set?

YES Replace the G and yaw rate sensor (Refer to Service and Repair). Then go to Step 6.
NO Intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 6. DTC recheck

Erase the DTC.

Q. Is DTC U1003 set?

YES Replace the hydraulic unit (integrated with ASC-ECU). (Refer to Active Stability Control System (ASC).) Then go to Step 7.
NO The procedure is complete.
STEP 7. DTC recheck

Erase the DTC.

Q. Is DTC U1003 set?

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