36-DTC U0401 ENGINE (CAN MESSAGE)

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

OPERATION

Engine-related signals are sent or received to and from between electric parking brake ECU and engine control module (ECM) via CAN bus lines.

DTC SET CONDITIONS

The DTC will be set under any of the following conditions:

The system receives an invalid accelerator pedal opening angle signal.
The system detects an implausible accelerator pedal opening angle signal.
The system receives an invalid engine torque signal.
The system detects an implausible engine torque signal.
The system receives an invalid engine speed signal.
The system detects an implausible engine speed signal.

TROUBLESHOOTING HINTS

Malfunction of engine system

Accelerator pedal position sensor
Volume volume air flow sensor
Crank angle sensor

The CAN bus line is defective (noise interference).
Malfunction of the electric parking brake ECU

DIAGNOSIS

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

(1)

caution

To prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).

Connect scan tool (M.U.T.-IIISE). Refer to "How to Connect the Scan Tool (M.U.T.-IIISE)

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

(3) Diagnose the CAN bus line.

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

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 whether the other DTC is set.

Check if the DTC is set in the ECM (Refer to GROUP 13A - Diagnostic Trouble Code Chart

Is the DTC set?

Troubleshoot the ECM DTC (Refer to GROUP 13A - Diagnostic Trouble Code Chart

Go to Step 3

STEP 3. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.

Check again if the DTC is set.

(1) Erase the DTC.

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

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

(4) Check the DTC.

Is the DTC U0401 set?

Replace the ECM (Refer to GROUP 13A - Engine control module

). Then go to Step 4

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction

STEP 4. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.