EGR circuit... Cleaned it, still CEL. Now what?

Hello all,

About a week ago a CEL showed up. Had a parts store pull the code: P0401, insufficient EGR flow. Thanks to advice on this forum and on YouTube, I figured out how to remove the pipe, valve, and cooler. Really a pain, but I got it out, got it all very clean, and got it reinstalled. Tip I learned: brake cleaner does not work well enough, but carb cleaner does. Changed spark plugs while I had everything apart. Car is running like a top, as it did before all of this.

Problem is, I've driven about 150 miles and the CEL has not gone out. What should I do? I haven't disconnected the battery, reckoning that if the CEL goes out by itself, it's actually fixed. If I force it to clear, I don't really know.

Car is a 2010 with 109,500 miles.

What do you think?

Thanks in advance!

 

Very true. Everyone should check that before undertaking this task. I do have the warranty enhancement, but unfortunately it expired March, 2017.

I'm hoping folks have experiences with what to do / what happened in their case after they cleaned the EGR circuit.

Thanks!

 

Thanks Ray,
I got the valve, cooler and pipe very clean but definitely did not do the intake manifold. You think that the manifold could be dirty enough to cause low flow later in the circuit, without experiencing any performance problems? It seems odd. If I need to do that too... guess I will!
How did the CEL work for you? Did you disconnect the battery or did you wait and the CEL went off on it's own?

 

Every connector was carefully cleaned and re-plugged. Car is running perfectly. Tomorrow I'm going to clean the intake, change the pcv valve while I'm in there, and hope it takes care of the CEL. Thanks-

 

Removed and cleaned the intake today. It was definitely oily and dirty, much like those on YouTube, but the visible parts of the egr passages were not blocked. Got it pretty clean and ensured the small passages were fully flowing. Oily material did not dissolve as readily as that on the egr valve/cooler/pipe so it took a while. Removal and re-installation was so much easier though. Replaced pcv valve while in there. Reassembled everything and car runs great. CEL still on, but only had chance to drive 17 mil so far.

Question about CEL & codes: Now that I've cleaned everything, should I disconnect battery or just keep driving? What did you do after your egr circuit cleaning?

Have to pass emissions in only a few days. This is getting old! Never had this issue with my wife's 2008, and I hope we don't with her 2017 Prius v. Only 8,000 miles on that one so far.

Thanks.

 

If you mean the bottom one (i.e., red in Mendel's note), I used an extension, with a universal joint between the extension and socket. Picked a viable route between the maze of cables and hoses. Not easy. Once I got it on there, I kept going regardless of how many cuts and scratches I was sustaining. I only removed the nut from that one, not the stud. On the back, exhaust end (i.e., blue), I laid across the engine and mainly used my left hand, with a regular wrench an ratcheting wrench to remove the nuts, then removed the studs too. Not nearly as hard as the bottom one.

 

Updating...
After doing the intake manifold, so that the whole circuit was clean... egr pipe, valve, cooler, plus replacing spark plugs and pcv, I ended up disconnecting the battery to clear the CEL. Came back on less than 20 miles later. I have only driven maybe 45 since disconnecting the battery. Just hooked up the OBD reader and still pulling P0401. Anything else but a bad egr valve that it could be at this point? I'm leaning towards buying the new valve. Hate to chase the problem with $ if I haven't diagnosed / eliminated things properly.