Electrical Power Steering System (EPS)

DTC U0415 Vehicle speed (CAN message) data input malfunction

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 Diagnostics Chart ).
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION

EPS-ECU receives vehicle speed signal from the ASC-ECU.

FUNCTION

The vehicle speed signal is sent to the EPS-ECU for motor control.

TROUBLE JUDGEMENT

Check Conditions

- The power supply circuit system DTC C1540, C1541 is not set.
- The DTC related to ASC circuit system is not set.
- The engine circuit system DTC is not set.

Judgement Criterion

- Abnormal vehicle speed signal sent to the EPS-ECU is received once or more.
- Abnormal vehicle speed signals are sent from the ASC-ECU, and engine control module, and the microcomputer determines that there is a problem in the vehicle speed measurement system.

Fail Safe, Back Up Function

The EPS-ECU illuminates the electric power steering warning display, and sets the DTC U0415 to limit assist operation.

PROBABLE CAUSES

- Malfunction of CAN bus line
- Malfunction of the EPS-ECU
- Malfunction of the ASC-ECU

DIAGNOSIS

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

(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 U0415 set?

YES Go to Step 3.
NO This diagnosis is complete.
STEP 3. Using scan tool MB991958, check the data list

Check the following service data Data List Reference Table.

- Item No. 08: Vehicle speed

Q. Is the check result normal?

YES Go to Step 5.
NO Perform troubleshooting for ASC-ECU Active Stability Control System (ASC). Then go to Step 4.
STEP 4. 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 U0415 set?

YES Replace the EPS-ECU (Refer to Service and Repair). Then go to Step 5.
NO Intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 5. 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 U0415 set?

YES Return to Step 1.
NO This diagnosis is complete.