P0401/EGR CEL code is back??

Did I not clean it good enough?

2 months ago this same code popped the CEL, with instructions from here, I cleaned it and it took care of the problem for almost exactly 2 months.

CEL came on again today, per Autozone, same code as before.

What now?

Truck has 151k miles, have never cleaned EGR before 2 months ago - was a bit gummed up then.

in rare caseing the circuit board in the egr fails. I think there is a how to in the faq's on cracking it open to fix it.

Check it out.

http://isuzufaq.ibctech.ca/EGR.doc

Ramblin, you've got the old style vacuum actuated EGR? Those have a seperate controller/feedback mechanism. These devices look for a pressure differential between the in and out of the EGR to show that it's working when being asked to (they are called DPFE sensors on fords). Common failure point. They get contaminated with moisture, get vacuum leaks, corroded connectors, etc. I'd look into that!

G/luck
Joel

Ramblin, you've got the old style vacuum actuated EGR? Those have a seperate controller/feedback mechanism. These devices look for a pressure differential between the in and out of the EGR to show that it's working when being asked to (they are called DPFE sensors on fords). Common failure point. They get contaminated with moisture, get vacuum leaks, corroded connectors, etc. I'd look into that!

G/luck
Joel

Yes, I believe it is the old style - '97 V6.

Do you know where this DPFE type mechanism is located on this engine?

I kind of wondered about this 2 mnths ago, as I did find a few forums about the fords having same issue. Seeing as it appears to be a rarity for this EGR set-up to get clogged like the newer years.

Today when I started the truck, after sitting for 2hrs in 40F temps, there was this wicked flapping type sound - it sounded like something flapping against something and not being able to open or spin all the way?? It lasted for 20-30 seconds and abruptly stopped.

Definitely coming from the engine compartment, similar sound to maybe a card stuck in a tire spoke - that's the best I can describe it.

Idle is still at 750rpm's but it feels a little rough, still running good though.

Thanks for the info.

Not sure about the noise, but the sensor might be mounted on the firewall. You will need to locate the EGR valve & trace the vacuum line from the dome of the EGR valve to where it originates. There will be tubing connecting the EGR valve with the dP sensor. The sensor will also have an electrical connector and vacuum going to it.

G/luck
Joel

Cool thanks, I'll check into it.

Noise hasn't occured again.

I will clean the EGR valve again and look into maybe cleaning up the connections to the sensor - may only get another 2 mnths and then again, the Valve could have another peice of carbon in it. That's what was in it the first time.

Thanks again - I'll keep you posted.