need help with oem codes

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by regcab, Feb 16, 2013.

  1. regcab

    regcab New Member

    ok so today i bought a truck and well either way on monday im gonna call and complain. but 2 and a half hour drive and dealer said every mechanical thing was perfect and showed me the information and that it checked out for there lot, test drove and seemed fine. well 30 min after i left check engine light comes on so on way home got it checked at autozone. codes were p0171, p0174, and p0101. trying to figure exactly what they mean but can really find straight answers? but what does this mean if someone who knows all this stuff could help. i dont know if it matters but it is a 2004 chevy silverado 1500. 5.3 v8 flex fuel.
  2. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Based on those codes (which you can readily Google), it's most likely a mass airflow sensor issue. Perhaps it is dirty. Perhaps the connections to it are poor. Perhaps it needs to be replaced (they are spendy)...
  3. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    The meaning I'm giving you are from my 96-98 trucks codes but they are pretty much the same on current trucks.
    P0171: fuel trim lean bank 1
    P0174: fuel trim lean bank 2
    P0101: as Surreal said MAF system performance problem.

    So pretty much your truck isn't injecting as much fuel as air is coming in causing a weak fuel to air ratio. This means the MAF isn't reading accurately and is telling the computer the wrong amount of air that is coming in to the intake. If you replace please use only AC Delco parts or you will have another problem down the road.

    Btw Welcome to the GMTC!
  4. regcab

    regcab New Member

    Last edited by a moderator: Aug 20, 2014
  5. shibby2oo8

    shibby2oo8 Member 2 Years 100 Posts

    With that code it sounds more like the sensor itself like Conlan said than just a vacuum leak, prob need a new sensor. Have to watch buying a used car, last fall my uncle picked up a 07 colorado and brought it over for me to look at. Had mud everywhere even in the above door grab handles, been wrecked on the whole drivers side and cheaply repairedand a list of other probs. it had a clean car fax and dmv report but the previous owner was a fleet and it was used for statue of liberty mait and was repaired in house so the hell it went through was undocumented. Iwould test every switch, handle, button, function, light on the thing, spend a hood hour with a fine tooth comb to give you some ammo to go in there with. I took his truck back with him and walked around it with the sales person for a good 20 mins bitching til they gave his money back.week later the truck was back on the lot, priced at kbb agian. Sorry i just realized how much i rambled but with used cars you have to spend time to avoid getting screwed.
  6. regcab

    regcab New Member

    ino i just i figured since from a dealer itd be trust worthly but guess not. imma try to clean it and check wire first but how much they cost?
  7. shibby2oo8

    shibby2oo8 Member 2 Years 100 Posts

    $125 ish with a core charge usually. You can clean it but if its throwing a circuit code it prob toast. Is there an aftermarket intake or filter on it? These are sensitive to filter oil from k&n type washable filters.
  8. regcab

    regcab New Member

    ok got the truck pretty decent so thats not to bad as long as thats the problem. ha and no its stock
  9. j cat

    j cat Epic Member 5+ Years 1000 Posts

    with the MAF code and the lean codes on both banks 1/2 this I guess would be a leak between the MAF and throttlebody. could also be leak in the upper intake . loose IAC or PCV crankcase venting etc oil dip stick no seated some other vacuum leak. A 2004 5.3L I think does not have a PCV. internal to driverside valve cover ?

    - - - Updated - - -

    so you on your drive home from a "dealership" you had the DTC check engine light come on. what was the warranty ? most likely they reset the PCM before selling to you . was this GM sales or auction buyer auto/truck sales ?
  10. regcab

    regcab New Member

    bought it from johnson motors in menominee, wi. of course had to sign off on that everything was ok. so called and bitched today but they say not there fault. so pretty pissed. sodont buy from Johnson Motors!!!!

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