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"Sevice Engine Soon" days after air filter replacement

2130 Views 9 Replies 7 Participants Last post by  sierra99
I have an 04 Armada (same motor as a titan) and have 70,100 miles on it. Last week I replace the air filter with a fram air filter. 3 days ago I have had my "Service engine soon" light go on and my gas mileage is terrible and very noticeable. I took it in to an auto parts store to get the code read and it is a P1279 code (Fuel /Air metering) or a air/fuel ratio Sensor. I looked again at the air filter box and i did see orange from the air filter and noticed that it was not completely installed correctly. I have taken off the clamp and totally removed and re installed the air filter and air box. I now see no orange at al from the air filter and I am 100% sure that the air box is installed correctly, and no wires or sensor connections are off or loose.

I have a pretty good knowledge of auto motors but with all of the sensors now days, I dont know where to start looking with out some tutelage.

the parts guy told me that the air box couls be totally removed and still not give me a code or a "SES" light, but I think he may be wrong.

I have not driven the truck yet but will tomorrow.

Could this air filter and air box not being totally sealed cause a p1279 error code?

If not where do I look now??

If I take it in I know they will just start replacing parts untill the code is gone
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Flash your ECU
By flash your ECU ,do you mean reset the ECM?
After the air filter is correctly installed, reset your ECU. Search for that topic on these boards. From what I gathered, it's pretty easy to do.
Was the filter real oiled down? If it was and possibly installed wrong, you could have gotten some oil on your MAF. Or it could have been reading too much airflow if the filter wasnt seated properly too. Check all the small details first, then reset the SES light. Then possibly try to reset your ECU, that never hurts anyway because the ECU learns how you drive and adjusts accordingly. You basiclly start off with a fresh OEM tuned truck by doing so. Good luck and let us know what you find.
the old filter was pretty bad and the new one is oil on it likw a k&N filter. Is ther a differenc between resetting the SES light and resetting the ecm and resetting the ECU or is the ECM and ECU the same????
Could it be the MAF is gunked up?
I would pick up a can of MAF sensor cleaner, clean it, then reset the ECU (there's a DIY here about just how to do it). You should be good to go then.
You can either choose to reset your ecu or just keep driving it and the "SES" light will go away. I'd rather that you reset the code with an OBDII code reader, that way, your ecu map doesn't have to start over. It takes about a week or two of driving for the ecu to relearn. What probably happen was your air filter was probably dirty as hell for a long time and the ecu got used to it. Then when you put a clean, more free flowing filter on, the ecu threw a code saying it's getting too much air because of the improper installation and freer flowing filter. Nothing big to worry about. If this is all you did, I wouldn't mess with the maf, you might damage it and it will cost more money to have it replaced.
just did the "EASY" reset and worked 1st time and 2nd time. Easy is the way to go, but the code is gone and SES light is out. Drove for 5 miles and light is still off.

I will drive about 300 miles sunday and we will see if it is still off..

Thanks guys...
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