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EGR Code P1406

Old 07-07-2019, 10:02 PM
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Default EGR Code P1406

On the way home yesterday the ole check engine light came on, ding ding. Had the scanner in car and the 1406 was a bit of a surprise.
Lifted the hood checked connection and said huh the car just got 43mpg what, and then realized it was possible a burnt off chuck of carbon could be responsible on the pintle.
Decided no way I am dealing with this on side of the road, and drove the rest of the way home, no issues.
Now I do not know why they would design a bracket around the EGR to make sure with man hands, you are probably going to drop the nut into the abyss without a 13mm magnetic socket.

I used my handy telescopic pick up tool to remove the nuts once they were loose, and it really helped for re-install as well.

I cleaned the EGR Pintle with carb cleaner and port. Pintle looked clean, moved freely & did minor scraping around the pintle seat area.

I hope that solves the 1406 issue.
I also wonder if I should clean the Maf Next?

Last edited by Soft Ride; 07-07-2019 at 10:04 PM.
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Old 07-08-2019, 09:55 AM
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Wouldn't hurt to clean it, but only if you have a way of resetting your fuel trims so that the ECU can relearn. I'm not sure if GM platforms reset fuel trims when the check engine light is cleared out.
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Old 07-08-2019, 01:56 PM
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Thanks for that information Mike.
I think I will leave MAF alone for now, as it displays no codes or symptoms of any stalling, high rpm, or other related issues.
Even though I think this is a GM MAF Part, are these the corrects screws? I thought they should be Torx bit?

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Old 07-08-2019, 02:30 PM
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Some are Torx, some are Phillips. I've been watching these in the yards for years. Doesn't seem to be a rhyme or reason that I can see by make/model or if the MAF is original or replaced.

A sign on MAF going out is sluggish performance from a dead stop. My 1997 LeSabre used to have this from 0MPH to about 10MPH. Step on the gas any amount (from barely touching it to WOT) and it would do parking-lot acceleration until about 10MPH, then start acting like normal. Tall gear ratio and high altitude made this miserable and had to really plan out some acceleration events in traffic. All other speeds ran as they should, and when the engine was cold it didn't have the issue. No codes set. Cleaned the MAF with MAF cleaner, changed a few sensors, all the plugs, all the wires, etc. to attempt to troubleshoot this and no luck. Finally found a 3800 in a yard that still had the same model MAF as mine (they're the first part to go around here) and swapped it in as a cheap experiment. Voila' all fixed, like night and day. That was probably ten years ago. Same MAF sensor is still on it today.
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Old 07-08-2019, 06:02 PM
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^ Good information about Maf there CC.
Even though I have not tested the performance at mountain altitude lately, I can say my PA runs great with a very smooth idle & will chirp the tires off the line no problem.
I also run non ethanol 94 octane, & the Buick gets way better mileage with this fuel, with an occasional Techroline Concentrate additive a few times a year. This engine should be clean!
I just came from another hwy test in the car about 60 miles with some city mix and car hot. All is well as no codes coming back so far.
Actually seems smoother today, hopefully the EGR cleaning did the trick.
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Old 07-08-2019, 06:58 PM
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I've seen both also. Actually, now would be a good time to break those screws out and apply anti-seize to them. Leave the sensor in place though, the bottom part of the sensor housing tends to break off inside the TB, which will actually cause the engine to run like ****.
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Old 07-08-2019, 07:26 PM
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Originally Posted by Soft Ride View Post
Even though I have not tested the performance at mountain altitude lately
FWIW during this issue, I did drive it down to ~3,000 feet and the issue was still there, just a little less pronounced.

Originally Posted by Soft Ride View Post
I can say my PA runs great with a very smooth idle & will chirp the tires off the line no problem.
LOL, I haven't seen that from mine in years, even when I used to have the skinny 205'* on it. E10 gas plus altitude plus tall gearing.

Originally Posted by Soft Ride View Post
I also run non ethanol 94 octane
That would help. Mine'* never seen anything higher than 93 octane, but that was long ago on the West coast. Out here the pumps top out at 89 octane thanks to the altitude. Every once in a while I can find some non-Ethanol fuel, but usually that'* in Nebraska, Wyoming, or South Dakota.

Originally Posted by Soft Ride View Post
I just came from another hwy test in the car about 60 miles with some city mix and car hot. All is well as no codes coming back so far.
Actually seems smoother today, hopefully the EGR cleaning did the trick.
Woohoo!
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Old 07-08-2019, 07:31 PM
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Originally Posted by Mike View Post
now would be a good time to break those screws out and apply anti-seize to them.
That'* an excellent idea. Every one I've touched has felt like I was going to break the screw when it first comes loose. I hadn't thought about anti-seizing my own. Duh.

Originally Posted by Mike View Post
Leave the sensor in place though, the bottom part of the sensor housing tends to break off inside the TB, which will actually cause the engine to run like ****.
I never liked how thin the housing is around the hole. I haven't had one break but it wouldn't surprise me if it did.
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Old 07-11-2019, 06:59 PM
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Originally Posted by Mike View Post
I've seen both also. Actually, now would be a good time to break those screws out and apply anti-seize to them. Leave the sensor in place though, the bottom part of the sensor housing tends to break off inside the TB, which will actually cause the engine to run like ****.
Yes sounded like a good plan to me Mike, & today I got er done.
Did not remove MAF (no codes still) and used a bit of deep creep before breaking them free.
Anti-seize used along with new identical stainless steel Phillips screws!
They wont rust LOL..
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Old 07-11-2019, 07:33 PM
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Originally Posted by Soft Ride View Post
along with new identical stainless steel Phillips screws!
They wont rust LOL..

I can see the sparkle from here! Pretty!
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