If you have a minute can someone take a quick look at this scan. I'm having a reoccurring issue around 10 minutes into my trip when I'm cruising my O2s go lean and i see 15-16afrs. If I give it some petal when I see this occurring it snaps out of it. At first I thought I may have had a MAF failing and was defaulting to SD. However, I replaced MAF with a new one and same thing.
Thank You in advance for looking!
Last edited by slowmo934; 09-26-2014 at 02:51 PM.
Going to take a wild stab here and guess that you have no cats and that you no longer have the rear o2 sensors on the vehicle at all.
Does the truck ever just go at random times rich aswell and then lean and they always seem to happen at different times?
I had this problem untill I plugged back in my rear o2 sensors and just zip tied them to the frame. It's like a cat test that you can't disable, but having the sensors plugged in allows for only 1 test after it hits closed loop and then it won't do it again.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Yes you described it pretty well. I will have to dig around and see if I still have the sensor #2s and plug them in to see what happens. Thank you
If you do find them and get them in, go a drive and figure around the time it switches over to closed loop (if you are running it that way and depending on temp) it will try to do a rear o2 sensor/cat test. The wideband should read rich around 12.5 to 13.5 for about 1 minute or so, but you must keep the vehicle speed above 15-20ish mph and rpms above 1200-1500 as anything lower it can snap it out of it. It should do the test and go right back to it's regular sweeping of around stoich and it won't happen again on that drive cycle.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Just disabled all sensor 2 stuff, no rear O2s in place, and 12 minutes into ride it's still doing it. Attached the scan and you can see around 12min it goes lean then rich. I did not find my old rear O2s to connect just to see if it would stop doing this. Hard to go spend money on a useless part.
I see whats going on and it's pretty much doing what I said, only plugging in the rear o2's will fix this. Even with everything shut off and all codes disabled, once they are in place it will run the test once and go rich for 30-60 seconds and never again.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Ordered two rear o2s from Amazon. The o2s will be here tomorrow, I will update with my findings. Thank you for the help. Below is an interesting link that address this problem on a TBSS.
http://www.tbssowners.com/forums/showthread.php?t=74260
I hooked up the new rear o2s and sure enough problem solved. About 13 minutes into trip it went 1 point richer for a minute then back to normal. Thank you for the help!
Yup no problem.
Kinda of a stupid thing to deal with but it is what it is.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Thanks for sharing! I never knew this but had seen some strange behavior like this before I went open loop about a year ago.
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