2019Sierra

I cleaned the ground wire. It wasn't that bad but I haven't had it happen since. Not yet at least.. I would feel more confident that the problem was the ground wire if it was actually corroded. I never did check UBEC.

Thanks Silverasodid. I don't have time to get too far into it today, but I did have a look at the connection on the frame. It wasn't too bad, no rust, but I wire brushed the frame and cleaned the lug on the strap.

Back in January, after driving my truck to town, stopping and starting a couple times, it wouldn't start. After half a dozen tries, it started but the check engine light was on. I couldn't get a hold of the shop I go to, but after 3 days, the light went out. Everything has worked fine since. Today, while in for an oil change, they did a scan and found codes P062B, P1682, P16A7 and P16BC. They told me it's either the MAF Sensor or wire chafing. I did find Service Bulletin 21-NA-032 online. I have no idea if this is the right bulletin but it looks like it might be. It says to check UBEC connector X3, position H6. Sounds easy enough.. but.. where and what is UBEC (I assume is the fuse block under the hood) and how do I get to X3? If that's not the problem, where else should I look? As it stands now, I don't trust this truck and don't want to be stranded on the side of the road or in the bush somewhere.. Thanks.