[dyam]

2017 Colorado Z71 (25,000 miles-never a problem before) towing a boat, about 4,000 lbs max, in tow/haul mode traveling down a long downhill highway, Gaviota Pass. Hit the brakes to slow and usually the trans downshifts so that the exhaust brakes can help slow but not this time. After a few mile the trans quickly down shifts 2 or 3 gears and revs really high. I shove it in neutral and then back into drive and the truck goes into Reduced Power mode. Check engine light comes on.
So I'm coasting down the pass looking for a place to pull over and end up drafting behind a big rig. Then the engine shuts down and will not restart.
Now I'm really just coasting and go a little longer and the power brakes go away. Finally get to the bottom of the pass and there is an area next to a rest stop that I can pull into.
Tried to restart and every time the dash goes blank and engine will not crank.
Call Auto Club and get the towing process started.
After about 10 minutes the engine starts, no reduced power but a check engine light is still on.
Was able to drive home, another 70 miles, with no other issues.
Goes in to the dealer tomorrow to see whats what.

 

[Burgess159]

That’s scary. Glad you’re okay though. Hope they find the cause to the problem

 

[dyam]

Thanks!
Service guys are going back and forth with the Chevy Tech guys to try and ID the problem.

Doesn't sound like they have a clue though.

I would have thought it would have thrown a code that would help but what do I know.

 

[dyam]

So I got my truck back after 2 days.
They found a P25BD code, unmetered fuel-forced engine shutdown.
They checked oil level from crankcase and excessive engine oil at air cooler assembly.
No oil detected, no drips or puddling noted.
Reassembled and drove for 28 miles.
No abnormal engine concern noted at this time.
So I guess at best this is a one time deal and at worst its the start of something.

I will not be using the tow/exhaust brake mode anymore.

May start looking into a gas silverado.