Check engine when cranking

[strafingmoose]

Hey there

 

So I've Googled the problem quite a bit and found nothing of interest about it. For a while now, I've been seeing the check engine light come on while cranking the truck.

 

It'll turn off as soon as it's started though.

 

Did not go to the dealer yet, but this shop I went to did a TSB on it related to a possible anti-theft system shortcircuit. They said they found a code in the memory saying such (I don't have the code on hand right now, I'll post it later). They cleaned a bunch of electrical grounds and even added a new one, no luck. They say there's another part of that TSB that needs to be completed, but I wanted to get some opinions about it before going ahead.

 

The truck works fine, except for that light that comes on when cranking and off when started. It's just making me nervous to see the light come on like that. I wouldn't want to be stuck in a boat launch or deep in the woods with a dead truck.

 

Ever seen that problem before ?

[newdude]

Has it done it since you purchased the truck? 99% of vehicles these day, when you key on (the spot before crank) the light comes on, and then while cranking and for a second or two after firing the light stays on then goes off.

[schnid21]

I'd be pretty sure all your seeing is a bulb test. Normal start up process.

[maplesig]

Yes the SES comes on all these trucks when started.

[Gurrzt]

My 2013 Yukon Denali does this, in fact all the warning bulbs light up @ start up, as stated above, it is some sort of test.

[MikeNH]

It's called prove-out. All the lights come on for a bit. This is nothing to worry about as it is working as intended.

[strafingmoose]

The weird thing is that sometimes it does turn on, sometimes it doesn't. I had this problem this winter where my battery cables were not connected properly and lead to a charge problem. It once or twice did not crank and had the check engine light on.

 

Then this anti-theft code on and sometimes it would simply not crank (after fixing the loose battery cable issue) but would always start on 2nd try. I guess that was the anti-theft shorting and getting in the way and choking the ignition. Got a part of a TSB done on it, so I don't have this problem either.

 

But the check engine does come on from time to time when cranking, so really, after all this, I'm a bit confused as to what is the normal behaviour!