What is your question?
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What is your question?
3.5 liter with 190k buick and I have a p0404. I replaced the egr valve after running the tests listed in http://easyautodiagnostics.com/gm_egr_diagnostic/egr_valve_test_3.php. I still have the code and problems, do I need to reflash the pcm?
2 Replies
Check with the dealer for possible Technical Service Bulletin (TSB) issued to diagnose/correct this problem..
yes, I plan to call the dealer this week and see what they say, I am sure they will say come on in and they will diagnose for 1 hour labor, but good idea I will ask them to check for any TSB and the cost of updating the pcm
TSB-60604003
ok thanks
yes I cleared the code immediately after replacing the egr, code and symptoms were still there
The EGR obviously is not the problem. What was the code # and who diagnosed the valve.
In the original post I listed the code p0404 and the diagnostics I used. I also used the shop manual, but my scan tool cannot give commands so I was limited in the shop manual test. the diagnostic web site is excellent and I used it before, I followed that and it concluded egr valve. Yes it is possible that it could be the pcm or a wire. the manifold is not clogged as I ran the car without the valve and clearly the passage is open. the delphi replacement egr had instructions that said it may need calibration after installation, before I go to the dealer I wanted to see if anyone else had to do that. after replacement I still get the code, poor mileage and poor acceleration, I plan to check around with other mechanics, then hit the dealer, thanks
Use the Siemens valve kit. Not the Delphi.
I will check out a few more things and if nothing else works I will switch to the siemens. what is wrong with delphi, they are oem? will a pcm flash not work? I understand the siemens needs a flash too. A flash will cost me about 125. I appreciate your help. have you experienced this too?
According to the TSB it says to use the Siemens and not the Delphi. And yes it calls for resetting. If were at the shop it could be ran with the scanner to double check it but you are giving it a go with the resources you have.
ok thanks, I'll let you know how this ends up. For now I disconnected the electrical connector so the car has power and I can get up hills. the egr is closed with no power. that also indicates the problem is the valve is opening more than what the engine needs. I plan to try the pcm flash next.
And it could be a fuel issue as well but let me know what happens.
more info on this- I also have a p0420 cat code for a few months and this p0404 egr code just appeared with the lack of acceleration symptoms. The car accelerates much better with the egr disconnected, but when it is floored it has the same symptoms. So I am thinking it is not the egr and maybe the cat. I plan to change the cat since that code is not going away. I have been through the cat tests- 02 sensor watching, temperature and thought it was not bad, but now it appears I have a clogged cat. I will change it and then clear the codes and see how it runs. I should have mentioned the 404 code, but now it may be apparent that it may be tied into the current problem.
If you have a 10 - 20 lb pressure gauge you could use the pre cat o2 port to see if it is restricted. Anything over 5 lbs is considered restricted. Sometimes you have to accelerate to 3000 RPMs to test for high rpm if not showing at idle.
I put a new cat in today and the car runs great, full power, feels like new again. Cleared the egr and cat codes. I will give it a few days, but I think it is fixed. So it appears the cat got bad enough to cause the egr code 404. I thought the cat code was minor due to the 02 sensor looking normal, inlet and outlet temp ok, no noise and no smell, but I was wrong. Also looks like the delphi egr does not need calibration. I probably did not need a new egr, but at 190k, at least I have a new one. Thanks for your help, a few lessons learned on this one.
Glad to hear it. I love it when it's all good. Happy motoring.