5.3 Sierra Throwing Codes

[Justheman80]

My truck is a 05 Sierra 5.3 with a K&N replacement air filter and aftermarket muffler, otherwise stock. I bought a inTune and filled up with 91 octane, then I installed the diablo tune. I have driven over 100 miles and I am getting p0131 and p0151 codes under hard acceleration. I have cleared the codes several times thinking my truck needed to learn the new tune, but they just keep coming. All my o2 sensors were replaced 3,000 miles ago and while in stock tune I am not getting any codes. I attached a data log where the codes pop up during hard acceleration, the rest of the log is freeway cruising.

Thanks for any help.

Also what settings do I need to change so that the fans act as stock or nearly stock?

[06MonteSS]

those codes are for your FRONT O2 sensors... so, something is wrong with both of your front O2 sensors and/or their wiring harnesses.. you need to get it checked out/fixed...

[avalanche04]

possible intake gaskets leaking??

[06MonteSS]

no, it's not an air leak/lean code... those are low voltage trouble codes.. has to do with the O2 sensors, electrical issue / their wiring...

[avalanche04]

not trying to start an argument or saying you are wrong but.....copied and pasted directly from the gm service manual for these codes...

 1. The HO2S may be detecting a lean exhaust condition or may be contaminated. Inspect for the following conditions:
Notice: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices.

◦A silicon contaminated HO2S
◦Any water intrusion into the HO2S connector
◦An exhaust leak between the HO2S and the engine
◦Any vacuum leaks
◦An incorrect fuel pressure—Refer to Fuel System Diagnosis.
◦Any lean fuel injectors—Refer to Fuel Injector Balance Test with Tech 2.
◦An inaccurate mass air flow (MAF) sensor—Refer to Scan Tool Data List.
 2. Repair any of the above or similar engine conditions as necessary.
Did you find and correct the condition?

[mikel]

best way to chase a code for the rest of your life is to follow the factory service manual.

You have to diagnose it yourself, using common sense and whatever info is available, going by the factory guidelines is a mess. I want to kill dealer techs sometimes when I watch them chase a dumb code, when it is plainly obvious to me whats causing it, but they love to go through these crazy procedures since GM says thats how you do it

[avalanche04]

oh come on...we're not all bad!! i'm just suggesting that its a possibility there may be another issue causing a possible lean condition under hard accell. i have seen it go both ways....electrical and mechanical and i'm not a fan of throwing parts at something to fix it. i have fixed many of these things over the years, a few o2's have been replaced but not a whole lot of them....just my .02. i will say the gm manual can lead you astray sometimes, but like you mike, i try to use common sense. if this truck only sets them under load and on both sides, i myself would be cautious about replacing both 02 sensors. i would even check the MAF sensor to make sure the sensor wires are clean too, that as well could cause low voltage codes to set (have personally seen it). not ruling anything out, just making suggestions. ok...off my soapbox (please dont kill me)

[06MonteSS]

http://www.gearchatter.com/viewpost14779.php

http://www.gearchatter.com/viewpost17819.php

[Justheman80]

When I installed the o2 sensors I placed they all locked in and I placed the factory plastic lock pin in all of them. I don't off-road my truck or have not done anything to cause wire harness issues and it appears to be in good shape. I checked there are no exhaust leaks. And it idles smooth, leading me to believe there is no intake leaks, gas mileage is decent.

Also I have switched back to the factory tune (over 100 miles ago) and I am not getting those codes and it did not get those codes with the factory tune prior to Diablo. With the Diablo tune those codes were popping up all the time! The obvious link is the tuner.

Does anything stand out in the data log? I don't have the software to view the tune.

[Justheman80]

Can anyone help with the problem I am having?

[06MonteSS]

i still say it's something wrong with your front O2's..

when you're WOT, your ltft's show 16%+.....

and when you're just cruising, they're not reading anything, all 0....

so something's not right with 'em....

[Justheman80]

I have attached a data log similar run to my first one, but with my factory tune. I did not change a single thing other than moving back to factory tune! I downloaded the data viewer software and I can see my o2's are there and giving me numbers at cruising. I am still learning, so I don't know what the numbers mean, but I know the o2s are working with the factory tune. I have tried going back and forth between the two tunes (with good drive time in between) and the diablo tune gives me engine codes (p0131 p0151) codes.

Could someone please look at the tune in this post to verify normal o2 activity and help to a resolution on this problem.

Thanks for the help I have received so far.

[Justheman80]

Help.

[sarah_ima64]

I need help last weekend my Chevy suburban turn on light check engine I had this codes p0420 p0430.

I installed shorty headers with stock cats.

Can you help me to turn off o2 sensor ?

[06MonteSS]

I need help last weekend my Chevy suburban turn on light check engine I had this codes p0420 p0430.

I installed shorty headers with stock cats.

Can you help me to turn off o2 sensor ?

I can certainly get you hooked up with a custom tune for your truck and mods, and disable the necessary trouble codes and related items, etc etc...

www.diablewtune.com

and you can email me at diablo DOT help AT gmail DOT com