Jim_rockford_007 Posted December 25, 2019 Report Posted December 25, 2019 found this a little while ago, thought folks might find it handy, Im going to try it for mine tommorow. Quote Pontiac Grand Am: DTC code P1404 arrie Posts: 312 August 2006 in Pontiac Many GM built cars have a tendency to have the 'Check Engine Soon' light come on as a result of DTC code P1404. P1404 is described as EGR valve pintle stuck open, which in most cases is a false alarm. I had this happen with my '01 Grand Am. A little bit surfing on internet reveals that GM has a solution for the problem, a re-flash for the car's computer. A software re-flash as a fix kind of indicates that the vehicles with this problem were built with it but I don't think GM will be re-flashing cars outside warranty for free. They will want their $100 for it. Some hands on people I found had purchased a new EGR valve and changed it but the problem remained. Possible reason (very likely) for the false P1404 code is that the plastic piston of the EGR valve position instrument (LVDT?) wears over time and starts reading a different position at valve closed than what it was when the EGR valve was first installed. When the car was built and the computer circuits energized for the first time the computer learned the EGR valve closed position signal from the valve position instrument that is built on top of the valve itself. Over time, when the instrument wears, a slightly different signal is sent to the computer and when it differs enough from the 'Valve Closed Signal', that the computer had learned, the trouble code P1404 is set and the 'Service Engine Soon' light comes on. Replacing the EGR valve with a new one does not necessarily fix this problem because the 'Valve Closed Signal' between valves is slightly different and it is just pure luck if your new valve would give a 'Valve Closed Signal' close enough to your original valve's signal not to set the trouble code. This is why the new EGR valve 'Valve Closed Signal' must be re-learned by the computer. So, what this all means is that if the P1404 is a false code meaning that the valve pintle is not stuck open, then new 'Valve Closed Signal' can be re-learned by the computer using the old valve. For fixing this problem the tool you need to have is a simple OBD II code scanner that can be used to erase trouble codes. There are many scanners of different price range on the market. I purchased one from AutoZone for about $90. A code scanner is a very handy tool to have and I recommend everybody who is just slightly hands on type of a person to get one. It will end up saving a lot of money over time. The fix goes like this: 1. Disconnect the wire harness from the EGR valve. 2. Turn key ON and erase the trouble code(s) from the car's computer AND TURN KEY OFF IMMEDIATELY WHEN THE SCANNER SAYS CODES HAVE BEEN ERASED. DO NOT TURN KEY ON BEFORE YOU RE-CONNECT EGR WIRE HARNESS. 3. Re-connect EGR wire harness and your problem should be fixed. I learned this fix from OBDII.COM where carfixer and kozloski discussed it and I think kozloski was the one who provided the solution, so thanks to them. There was also other people stating that this fix really works. Now I have joined this group of people as I got mine fixed using this trick also. I believe erasing codes with wire harness disconnected and turning the key OFF right after P1404 code has been erased re-sets the 'Valve Close Position' reading in the computer and triggers computer to re-learn position next time the key is turned ON. If you don't have an OBD II scanner and don't want to buy one some car part stores may erase the code for free, but if you have it done there you must tell them about turning the key OFF at the right moment. Other wise the re-learn process does not take place. Quote
digitaloutsider Posted December 25, 2019 Report Posted December 25, 2019 I had the same code thrown in my Regal, ended up being a vacuum line on the back of the blower that was broken. Check for vacuum leaks, too. Quote
walterdude Posted December 25, 2019 Report Posted December 25, 2019 (edited) "Sorry how this post came out!!! Below is a copy of a post I made in Sept on this very subject..." I happened to remember that I "thought" that I "might" have saved a note from a post I had msde on 60deg V6.com Maybe 20 years ago... AND after all those years and PCs that there is one folder on rhis PC that I always put on a new/different machine... Here is a copy... I didn't test if the link is still active,,, it WAS a LONG time ago... Speaking of Dead Links I see 60DegreeV6.com is officially DEAD... That SUCKS... Besides this site 60deg was the ONLY form of social media I ever engaged in... Well,,, hope this helps... Good luck!!! Tom B... Before when this first posted they pulled on of their FAMOUS Fire Drills... I just hit submit and hit the road... I see now that the codes are not exactly the same... I didn't have any thumping going on BUT everything else sounds familiar Running the reset won''t hurt anything AND it just might do some good... I'm back!!!! Just found this link and Explains the PCM Reflash... I'd say the 2 codes in question are VERY closely related... https://forums.edmunds.com/discussion/5667/pontiac/grand-am/pontiac-grand-am-dtc-code-p1404 Fix P1404.txt Edited December 25, 2019 by walterdude Quote
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