Code No. U0401: Engine (CAN message)
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- If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table
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- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
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OPERATION
Engine-related signals are sent or received to and from between electric parking brake ECU and engine ECU via CAN bus lines.
DIAGNOSIS CODE SET CONDITIONS
The diagnosis code will be set under any of the following conditions:
- An invalid accelerator pedal opening angle signal persists for at least one second.
- An abnormal accelerator pedal opening angle signal persists for at least one second.
PROBABLE CAUSES
- Malfunction of engine system (accelerator pedal position sensor)
- The CAN bus line is defective (noise interference).
- Malfunction of the electric parking brake ECU
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STEP 1. M.U.T.-III CAN bus diagnosis
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step 3.
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 Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.
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STEP 2. Diagnosis code recheck after resetting CAN bus lines
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Q.
Is diagnosis code No. U0401 set?
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Go to Step 3.
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This diagnosis is complete.
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STEP 3. Use M.U.T.-III to confirm a diagnosis code of other systems.
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Check if the diagnosis code is set in the engine ECU (6B3: Refer to GROUP 13B - Diagnosis Code Chart , 4N1: Refer to GROUP 13C - Diagnosis Code Chart ).
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Q.
Is the diagnosis code set?
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Troubleshoot the engine ECU diagnosis code (6B3: Refer to GROUP 13B - Diagnosis Code Chart , 4N1: Refer to GROUP 13C - Diagnosis Code Chart ).
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Go to Step 4.
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STEP 4. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to the LOCK (OFF) position.
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(3)Turn the ignition switch to the ON position.
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(4)Check if the diagnosis code is set.
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Q.
Is diagnosis code No. U0401 set?
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Replace the engine ECU (6B3: Refer to GROUP 13B - engine ECU , 4N1: Refer to GROUP 13C - Engine ECU ).
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Go to Step 5.
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STEP 5. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to the "LOCK" (OFF) position.
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(3)Turn the ignition switch to the "ON" position.
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(4)Check if the diagnosis code is set.
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Q.
Is diagnosis code No. U0401 set?
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Replace the electric parking brake ECU (Refer to ).
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
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