07 Silverado Ltz 2 Codes

cvfd1615 · June 15, 2011

Hello,

While sitting in the parking lot today idling the truck starts going crazy with beeps and messages.

First the check engine light comes on and stays on then all of a sudden I get two messages of " Service Traction Control " & "Stabiltrak Off ", Go to autozone and get 2 codes of P0171 and P0174.

Put the vehicle in gear and the traction messages and light goes off.

Am running a K&N Drop In Filter and all that and have a service appointment on Friday at my local dealer.

Anything the "shadetree mechanic" can do to try to resolve issues with this?

Notice no loss of engine power or anything like that.

Notice no performance in engine power or anything like that.

Any help woudl be greatly appreciated.

cvfd1615 · June 16, 2011

50 views and no help?

cvfd1615 · June 16, 2011

Just got in the truck and now the check engine light is off as if nothing happened...

Thoughts.

Willshire · June 16, 2011

Wheel speed sensors, computer glitch? google the codes to get clarification but, traction and stabilitrak are dependent on wheel speed sensors in the bearing hubs.

cvfd1615 · June 16, 2011

Computer codes showed MAF issues or whatever.

I'm kinda believing it is a computer glitch it hasn't done it since. I know any issues with the traction/stabilitrak would be covered under powertrain however, not sure about the other. I don't want to go to the dealer in the morning with it not reading any codes and just giving them 90+ bucks for a computer read when I already have the codes that read yesterday on a print out from autozone.

So should I cancel, wait to see if it does it again then go to the dealer for a service?

Wheel speed sensors, computer glitch? google the codes to get clarification but, traction and stabilitrak are dependent on wheel speed sensors in the bearing hubs.

Willshire · June 16, 2011

Silly question, did you try cleaning the MAF, i am sure there is a detailed instruction somewhere in here

ChevyTech77 · June 16, 2011

DTC P0171: Fuel Trim System Lean Bank 1

DTC P0174: Fuel Trim System Lean Bank 2

Have you run any ethanol lately? If you have, and you don't run the ethanol completely out before refilling with gasoline, or vise versa, or your engine isn't E85 compatible, those are the biggest things that cause those two dtcs to set in these trucks. Could have a vacuum leak too but of course there are many possibilities. Neither of those two dtcs are for a mass air flow sensor. The stability and traction systems will shut off, and notify the driver of said change, if you have any engine or transmission dtcs setting at any time, that is normal.

P.S. If you don't dab the extra oil out of any K&N air filter out of the box when its new or if you over oil them when you service them, you CAN wipe out MAF sensors quite easily. Again though, these dtcs aren't pointing that way. They point to crap or incorrect fuel or dirty injectors, for the most part.

cvfd1615 · June 17, 2011

DTC P0171: Fuel Trim System Lean Bank 1
DTC P0174: Fuel Trim System Lean Bank 2

Have you run any ethanol lately? If you have, and you don't run the ethanol completely out before refilling with gasoline, or vise versa, or your engine isn't E85 compatible, those are the biggest things that cause those two dtcs to set in these trucks. Could have a vacuum leak too but of course there are many possibilities. Neither of those two dtcs are for a mass air flow sensor. The stability and traction systems will shut off, and notify the driver of said change, if you have any engine or transmission dtcs setting at any time, that is normal.

P.S. If you don't dab the extra oil out of any K&N air filter out of the box when its new or if you over oil them when you service them, you CAN wipe out MAF sensors quite easily. Again though, these dtcs aren't pointing that way. They point to crap or incorrect fuel or dirty injectors, for the most part.

I put the K&N filter in about 8000 miles ago so wouldn't think that would be any issue never noticed it before hand.

My truck is not flexfuel and as far as I know I haven't added any fuel that shouldn't be. I thought it might be bad gas or something that triggered the codes but from yesterday the check engine light is now off and not having any issues and I tried to do the same thing just sitting somewhere in idle just like I did when all the bells started going off.

The stabilitrak and service traction light and messages only came on while I was in park idling, as soon as I put it in gear the light went off and as stated from yesterday to today it has not came on since.

So, I guess I could clean the MAS...

My main question is this:

Since I'm not getting those warnings now, the check engine light is now off, and the truck seems to be back to normal, should I still take it in? I know they will read it on their computer and then there is $100 bucks out the door just like that plus whatever the cost is to "repair" the issue that isn't arising now?

slomo007 · June 17, 2011

I had the exact same thing happen to me a few weeks ago. It also went away after I restarted the truck, but only after I restarted it twice?

I have no idea what caused it and it hasn't done it since. With 65,000 miles on the truck I think I'll wait until it's closer to the warranty expiration before worrying about it any further.

ChevyTech77 · June 17, 2011

I put the K&N filter in about 8000 miles ago so wouldn't think that would be any issue never noticed it before hand.

My truck is not flexfuel and as far as I know I haven't added any fuel that shouldn't be. I thought it might be bad gas or something that triggered the codes but from yesterday the check engine light is now off and not having any issues and I tried to do the same thing just sitting somewhere in idle just like I did when all the bells started going off.

The stabilitrak and service traction light and messages only came on while I was in park idling, as soon as I put it in gear the light went off and as stated from yesterday to today it has not came on since.

So, I guess I could clean the MAS...

My main question is this:

Since I'm not getting those warnings now, the check engine light is now off, and the truck seems to be back to normal, should I still take it in? I know they will read it on their computer and then there is $100 bucks out the door just like that plus whatever the cost is to "repair" the issue that isn't arising now?

Without the condition current, the most the tech can do is look the engine management system over good through it's stored data, check the fuel composition and possibly find something in those two things that could have caused it. It probably wouldn't hurt to get a fuel system clean done on the vehicle either, if you've never had one, just in case.