Hi there ... I'm brand new to the forum and from my searching on-line my issue seems a fairly common problem.

I have a 2008 Sport Trac, with a 4.0 SOHC engine ... 165k miles. Last week my check engine (CE) light came on and the code is P0401 ... too little flow on the EGR system. I first tried cleaning the existing valve - but CE light still came on. So I replaced the old EGR valve, cleaned the SS tube from the exhaust manifold back to the EGR valve and the CE light is still on. I have not driven the truck since I replaced with the new valve ... only fired her up in the garage. Is this something that could possibly clear up given a couple of miles?

I'm pretty much at the end of my tech expertise here and short of driving this to the repair shop, I sure could use some other trouble shooting suggestions on how to clear this up.

Thanks - Dorm

 

At least on older Fords it was pretty common for this code to be due to a faulty Differential Pressure Feedback EGR (DPFE) sensor. I'm not sure if they still use that in your 2008, or if it's still prone to fail. You might check the vacuum diagram under your hood or the parts houses to see if your truck has a DPFE sensor (also called EGR pressure sensor, etc.) and consider replacing it.

-Rod

 

In my initial post I noted that I replaced this. From what the parts house told me, the 2008 model EGR valve includes the pressure sensor ... so I have a new EGR valve, pressure sensor, etc. I also disconnected the battery to hopefully 'clear' the error code, but with no good result.

My question is what to do now, given that I've replaced these parts. Are there other sources to trigger the P0401 code and CE light?

 

So ... just to follow up here. I did more checking on-line on how to clear the 'error code' from the computer memory. Basically, I disconnected the battery, again, and drained any residual power in capacitors, etc. After 20 minutes disconnected, I also held down the horn button for ~45 seconds to totally drain it.

Hooked the battery back up - started the engine and no CE light ...

 

All I see in the initial post is that you replaced the EGR valve. The valve is different from the DPFE sensor. The sensor is what tells the PCM when to open or close the EGR valve. It is a separate part from the EGR valve, or at least it was a few years back.

With any luck the CEL will stay out for you and this code will not reset.

-Rod

 

Yes ... according to the AutoZone guy, this valve on the 2008 model includes the dpfe sensor - kind of an all in one valve.

Any way ... CEL is gone, truck passed inspection

 

Thanks for clarifying that the newer units are an all in one assembly. That's great that you were able to pass inspection, and it will be even better if the code stays away!

-Rod