How do I fix the P0401 code on my car?

Alton Alexander
By Alton AlexanderUpdated on June 4th, 2022

P0401 is an error code that indicates a problem with the exhaust gas recirculation (EGR) system. This code is often caused by a clogged EGR valve or restricted EGR passage. A clogged EGR valve can cause the engine to run too lean, while a restricted EGR passage can cause the engine to run too rich. Both of these conditions can lead to engine damage.

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1. Clean or replace the EGR valve

  1. Remove the engine cover.
  2. Locate the EGR valve and remove the cover.
  3. Clean the EGR valve with a clean cloth.
  4. Replace the EGR valve cover.

2. Clean the EGR valve passages

  1. Remove the screws that hold the EGR valve in place.
  2. Carefully pull the EGR valve out of the engine.
  3. Inspect the passages for debris or oil.
  4. Clean the passages using a solvent and a cotton swab.
  5. Reinstall the EGR valve and screws.

3. Replace the DPFE sensor

  1. Disconnect the negative battery cable.
  2. Remove the cover.
  3. Remove the front air intake scoop.
  4. Remove the air filter.
  5. Remove the DPFE sensor.
  6. Clean the sensor and replace if necessary.
  7. Reinstall the air filter, front air intake scoop, and cover.
  8. reconnect the negative battery cable.

4. Clean the DPFE sensor passages

2.Remove the DPFE sensor 3.Clean the sensor passages 4.Reinstall the DPFE sensor

5. Replace the EGR vacuum regulator solenoid

  1. Remove the front bumper cover.
  2. Remove the passenger side airbag.
  3. Remove the two screws that hold the EGR pipe to the intake manifold.
  4. Loosen the EGR pipe clamp.
  5. Remove the EGR pipe.
  6. Clean the EGR valve and the intake manifold. 7.Install the new EGR valve and tighten the clamp.
  7. Install the EGR pipe and screws.
  8. Replace the front bumper cover.

Some users might also have success with the following opitons:

  1. Perform a smoke test on the EGR system.
  2. Check for leaks in the EGR system.
  3. Check for a clogged or restricted catalytic converter.
  4. Check for intake manifold leaks.
  5. Check the PCV system for leaks.