Service Engine soon with P1404 code

[grampp1]

Ok, I have often consulted this website with answers on how to service my Grand Am (2001 3.4L V6), so I thought it was time to add some tech help of my own.

I recent had an issue with my Grand Am throwing the "Service Engine Soon" light. Well, first I went to AutoZone and had them hook it up, but it came out as generic code, so they reset it. The light came on the next day. I then had them hook it up again, but this time I thought to ask for the code: P1404. Thanks to OBDII.com, I was able to learn that this was related to the EGR valve pintle sticking. So, I'm not overly car savvy, but I wanted to know just where the EGR valve was located. Despite much searching, nobody had a picture, but I was finally able to figure it out. So, I took some pictures of my own GA (see attachments below) to hopefully help others.

So, then the next was to find a fix! Well, I came across all sorts of possible solutions from replacing the EGR valve completely, to cleaning the old one, etc, etc ... but alot of people continued to have the same problem. Now as a note.... my GA was only lighting the "Service Engine Soon" and was only showing the P1404 code. If you want to know the exact codes, I would highly recommend that you take your car to AutoZone, or "rent" the tool from AutoZone. As a sidenote, AutoZone has a loan-a-tool program that includes a OBDII scanner. Essentially you buy the scanner ($149), but as long as you bring it back, you will receive a complete refund, but if you decide to keep it, you did already buy it. I love the loan-a-tool program and have used it numerous time for many repairs ... wheel bearings, oil changes, etc, etc.

OK, so now onto a (potential) fix... this was posted on another site and seemed to cover all of the common issues I encountered in my searches:

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"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 of 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. :eek:

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.

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 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."

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Thanks to Aggie who I got this post from on Edmunds.com

Now, if the code does repeat, you probably truly have a problem and should plan to replace the EGR valve.

Hope this really helps someone on here as much as it helped me.

Thanks --- G

[JBlack16]

ahh crap wish i would have known of this earlier i just bought a new one because it happend once to me and then went away. 3 weeks later it just came on and i took it the dealer to get it fixed today dang. 160 bucks for nothing!!

[2K SE]

Very good info. Thanks for sharing.

[arthurgoboom]

Do you think this reset would work by disconnecting the EGR connector and disconnecting the negative battery cable for ~30 mins to reset the code, or does the key have to be on while you do it? I don't want to drive to the AP store if I don't have to.

My car threw this code today (P1404), suspiciously on the first trip after changing my front (ex. manifold) oxygen sensor.

Edit: Nevermind, I just took it to the AP store and did the procedure. So far the CEL has stayed off, it is about a 15 mile trip back and forth. So far this is a good thread :)

[gt00]

Do you think this reset would work by disconnecting the EGR connector and disconnecting the negative battery cable for ~30 mins to reset the codeNo :D

[GAJ83]

I just replaced the EGR on my 3800 equipped Firebird and posed a similar question to the F-body forum. When I replaced it, it seemed not to make a difference. So what you're saying is the thing needs a reset to relearn the new EGR?

[arthurgoboom]

That's apparently the case. What I got out of the article is that GM has a PCM reflash to take care of it, but running the above procedure apparently makes it relearn its "normal" values. *shrug* Sometimes it seems the cars drive us anymore.

[grampp1]

Well, it has been nearly 2 months since I originally posted the fix above and I am still going without a SES light anymore. I did have it come on once for about 2 days, then it went off on its own. I did check it at that time and it was the same P1404 code. Nonetheless, I will likely plan on replacing my EGR valve soon, as obviously, mine has turned out to be more than just a "relearn" problem. Still, I will use the "fix" to reprogram after I have installed the new part.

[arthurgoboom]

I'd like to leave an update here for future reference. I ran the relearn procedure and after about 100 miles the CEL came back on with the same P1404 code. Running the procedure 2 more times, as well as removing and cleaning the EGR valve still resulted in the P1404 returning after about 100 miles each time.

This last time it came on, I decided not to worry about it since I knew what it was and it didn't seem to be having any other effects. After driving an additional ~150 miles with the CEL on, the light went back off on its own. I am hoping that means that the PCM relearning just takes some time, and is not instant as I thought.

I talked to my GM service department about it, and they basically gave me the same procedure that is listed here, and kept talking about the "auto-zeroing feature" in the PCM.

[grampp1]

It has been near 2 month now since I ended up replacing the EGR valve on my Grand Am. I did reset/relearn after I installed the new one using te above procedure and the light has not returned (*knocks on wood quickly*) I have driven over 3000 miles+ since that time.

As a note, from reading various forums and posts, I don't think cleaning the EGR valve is a viable option. Most posts I read noted how the EGR valve in the case of the GM/Grand Am has a strong electronic influence and is hard to get the cleaners where they need to get to truly clean or fix the sticking or gunked-up pintle valve.

Nonetheless, my GrandAm has been doing ok since the install of the new part.

[Kodiak]

Grampp1,

You didn't mention whether or not you had any drive ability problems with your code. I understand that some 2001 get a code because of a firmware programming issue that its fixable.

My 2000 has over 220K miles and I'm getting the P1404 with stumbling and misfires. I'm going to RPL my EGR because I believe that mine is either worn or full of carbon to the point where it doesn't close when it should, hence the stumbling and misfires.

Regards

K

[arthurgoboom]

I'm not sure about the EGR valve on the 3400, but on mine, the valve sealing surface was right out in the open where you could clean it nicely with some carb cleaner and a toothbrush. It is basically a poppet valve much like the intake or exhaust valve, except instead of pushing out of the hole like a valve in the cylinder head, it is drawn down inside the EGR valve to open.

Kodiak, my P1404 came almost immediately after a tune up, I'm not sure if it was just coincidence or what, but I have a feeling that with my tune up, the emissions level changed, and the EGR valve had to work at a different position and it was "confused". Anytime you change any parts related to engine performance (spark plugs, O2 sensor, etc) Based on this I think you should disconnect the negative battery cable while you're doing the job, to force the PCM to relearn the timing and fuel curves so they'll be optimized for the new parts.