35C-DTC U0401: ENGINE MALFUNCTION DETECTED

DTC U0401 Engine (CAN Message)

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 (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
If DTC U0401 is set in ASC-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect DTC may be set. In this case, the set DTC is not highly reliable.
Before replacing the ECU, ensure that the communication circuit is normal.

OPERATION

Engine-related signals are sent or received to and from between ASC-ECU and ECM via CAN bus lines.

DTC SET CONDITIONS

This DTC is set when the engine control module malfunction has been detected.

PROBABLE CAUSES

DIAGNOSIS

STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.

Use scan tool (M.U.T.-IIISE) to diagnose the CAN bus lines.

Is the check result normal?

Go to Step 2

Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table

STEP 2. Using scan tool (M.U.T.-IIISE), check other system DTC.

Use scan tool (M.U.T.-IIISE) to check that the DTC is set in the ECM (Refer to GROUP 13A - Diagnostic trouble code chart

Is the DTC set?

Troubleshoot the relevant DTC(Refer to GROUP 13A - Troubleshooting/Diagnostic Trouble Code Chart

Go to Step 3

STEP 3. Check whether the DTC is set again.

(1) Erase the DTC.

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

(3) Turn the ignition switch to the "ON" position.

Is DTC U0401 set?

Replace the ECM (Refer to GROUP 13A - ECM

) and then go to Step 4

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions

STEP 4. Check whether the DTC is set again.

(1) Erase the DTC.

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

(3) Turn the ignition switch to the "ON" position.

Is DTC U0401 set?

Replace the hydraulic unit (integrated with ASC-ECU) (Refer to

The procedure is complete.