Q: Diagnostic code p0401

asked by on

I have changed the dpfe sensor the egr solenoid and the egr valve itself yet the check engine light continues to come back on with the same code.

My car has 315000 miles.

An often missed part of the EGR system is the passages in the exhaust manifold and intake manifold and the tube that connect the EGR valve to the exhaust manifold can become clogged with carbon. If there are any exhaust leaks, this can cause problems as well, but the most common issue after the DPFE and the EGR valve are clogged ports. Your ford will have rubber hoses that can become clogged as well. They are usually replaced with the DPFE.

A simple test for clogged EGR passages, is to remove the EGR valve and start the car. If there isn’t an exhaust leak, it is clogged. Remember to check the ports in the intake manifold as well. With the EGR valve removed, there will be a massive vacuum leak. If not, the passages in the intake are clogged. The hot gases meet the cooler intake manifold and condense, leaving carbon build up. Your configuration may differ from my description here, but what’s important is to check all the passages of the EGR system.

Cleaning clogged EGR ports can often be difficult and time consuming to clean. Often times removing the exhaust manifold and or the intake manifold is necessary. Once you have gained access to all the ports, you will need to dig the carbon out with a screw driver or large pick. This will take care of the majority of the carbon, but you should use carburetor cleaner to remove the rest. Often you will need to use a combination of carb cleaner and digging with a pick to thoroughly clean the EGR passage. It is in your best interest to remove as much as possible.

I’d suggest getting some assistance from a qualified technician, such as one from YourMechanic, if you need help with getting this done. A mechanic will be able to further diagnose your Check Engine Light and help you fix it accordingly.

Good luck! I hope this helps you out.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Diagnostic code p0401

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: How do i reset the computer after i change the crank shaft position censor?

To reset the check engine light you can disconnect the battery via the negative battery terminal and let the vehicle sit for an hour before reconnecting the battery. This will drain all of the power from the electronics and clear...

Q: There's a very loud clicking noise every few seconds from rear of car while driving

Hi there. This type of clicking noise is typically an indication of a brake pad that is dragging on the rotor or wheel bearings that are damaged. Most of the time if the sound increases in speed as the vehicle...

Q: Swapping 98 5.9l engine for 96 5.2l

The first clue is the EGR system. One engine has it and the other does not. Even though it may be illegal for you to change your vehicle engine from a 98 to a 96, as long as it is...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.