Cruise control problem

[Hellbillie]

When I engage the cruise control it will function OK. I can engage and disengage the cruise several times, but suddenly it is not possible to engage it anymore. I then have to stop the engine and restart, to get the cruise control in function again. There are no codes. I can disengage the cruise with both the brake pedal and the cruise switch, with the same result.

[Randee of the Redwoods]

I had somewhat of a similar problem. My cruise would work fine. While in traffic, if I activated the resume function, the truck would begin to resume with strong acceleration, then just quit. The cruise would not work until after the truck was turned off an restarted. The closest I can come to my problem is in the tranny. I have gotton one or two tranny slipping codes in the past. Me thinks the computer picks up the tranny slipping under the hard acceleration of resume, then cancels the command to avoid a runaway engine or broken tranny, then resets upon restarting.
Like you, in the beginning, I had no codes. I only had codes after running the truck hard. The slipping codes would come and go on their own. If you haven't already, try looking for codes immediately after the cruise fails while driving. That's what I did to get the tranny slipping code. I pulled into a gas station to fill up and checked for codes since the cruise had JUST failed on me while driving. Sure enough, fresh codes abound.

[MTTwister]

My cruise would just drop out randomly, but I also had random 'rolling' stalls, like a brief fuel cutout. It wouldn't always re-set, rarely reliable going down the road.

After 2 years of dinking around, the GM guys had it for 3 days. Told them when they test drove it with the scanner on, not to be in cruise if there was a Big A$$ truck behind them. Guess the first time it happened to the mechanic, and he wasn't expecting it, it scared the poop out of him.

Finally they replaced the IP. Probably the FSD, now that I've read up on stuff.

BTW - I left the PMD pump mounted for a 'back-up' when I installed the remote FSD. Who we kidding? No way in heck could I ever get the plug back in to the PMD with the clearance there. Sounded good, but it's not gonna work.

Anyhoo - after rambling - suspect could be the PMD / IP. Quick defuel would cause the cruise to drop out.

[Hellbillie]

Thanks for replay.

My cruise seems to work OK when engine is cold, or I just been driving 20/30 km. After running 20/30km. or when engine is starting to get hot, it is not possible to engage the cruise anymore.
The resume button is also working OK.(If the cruise is in moode to work at all).
Seems like the PCM recieve some signal that block the cruise control.
My EGR valve is disabled, and I havn't upgraded the program yet. Could that be the reason ?????