Error code P0401

Hi,

The specific code you have indicates "Insufficient EGR flow".

EGR stands for exhaust gas recirculation. Basically, the exhaust is drawn back into the engine to burn any unburned fuel via this system.

Since the code indicates there is a restriction, we either have a corrosion (carbon) build-up in the EGR valve, in the intake manifold itself, a vacuum leak, or the valve is not properly opening.

Here is what I need you to do. There is an air inlet tube between the air filter box and the throttle body. The EGR is under that area and mounted to the intake.

If you look at the pic below, I attached what it looks like. First, in yellow, I identified a vacuum hose that is attached to it. Make sure that hose is attached and not damaged, dry rotted, or cracked.

If the hose is good, we have two ways to do this. I would attach a vacuum pump to the EGR valve vacuum hose and see if the EGR is able to hold a vacuum. If it can't, the EGR valve needs to be replaced. If it can, then I would remove it and inspect for any blockage in the valve and inside where it is mounted on the intake.

I circled the two bolts and a steel tube that will need removed so the valve and be removed and inspected.

Let me know if you are comfortable doing these things. I'm here to help, so don't be afraid to ask questions.

Also, let me know how the vehicle is running. For example, does it have a rough or uneven idle?

Let me know what you find.

Take care,

Joe

See pic below.

Hi,

You are very welcome. I agree with your thoughts about being educated prior to going in. Once they realize you know what you're talking about, they are less likely to take advantage. LOL

Listn, you are always welcome here, so feel free to come back anytime in the future if you have questions or need help.

Take good care of yourself,

Joe