What would make cruise control turn off?

[Geotrash]

That's good literature @Geotrash thank you for that

Happy to help, and of course the subtext to all of that is that any electrical problems in connectivity, resistance in the wiring, bad grounds, etc. would all need to be troubleshot using a methodical process if after all of the items above have been conclusively ruled out as culprits. Alldata provides a guide for that in the Cruise Control section of the manual.

 

[Dustin Jackson]

I appreciate it, I think I've annoyed enough people with my "how does it work" questions for the time being lol

 

[iamdub]

You guys are usually not quick to resort to throwing parts at the problem so I’m sure there’s a good a reason for it but it hasn’t been explained to me yet.

I hope you can understand my caution to throwing my wallet at the problem without a little investigation, I would be surprised if there is literally no other reason cruise control would disengage other than a faulty brake pedal switch but that hasn’t been explained.

The first time my cruise control disengaged was accompanied by a check engine light so I know there are other parameters that can have influence on cruise control operation.

Also stated in my initial post the brake pedal switch was replaced when I bought my Tahoe 4 years ago

It's such a commonly failing part that, with no other symptoms pointing elsewhere, it's worth throwing the $16 and 10 minutes at. You're correct that there are other causes for the cruise to disengage and/or not set. As they said, it is automatically disabled when there's a drivabilty and/or safety (Traction Control, StabiliTrak, etc.) concern. Look at it from the other way: What if you went on a deep dive checking circuits, troubleshooting modules, sensors and switches and still drew a blank? THEN you replaced the switch and the issue never happened again? You'd be aggravated that you wasted a whole weekend crawling through your Tahoe when all you needed was 10 minutes to lay in the floorboard.

It's not a critical system and you could wait until it does it more frequently if you wanna get every cent out of the current switch. Speaking of, is it an OEM switch or aftermarket? If it starts happening more often, try those tests I listed to help confirm.

 

[Geotrash]

As they said, it is automatically disabled when there's a drivabilty and/or safety (Traction Control, StabiliTrak, etc.) concern.

100% agree with everything else you said but just one small clarification on this point. StabiliTrak and Traction Control faults won't prevent the cruise control from working. It's not listed in the disablers for the cruise in the troubleshooting guide, and the steering position sensor on my '07 has been throwing a Stab/TC light for a couple of years now and the TC still works fine.

 

[Dustin Jackson]

@iamdub @swathdiver I appreciate it guys, not so much of a problem yet just educating myself. The only other time cruise control shut off on me was when my lifter failed as you could imagine I just about shat my pants when cruise control turned off again unexpectedly

 

[iamdub]

100% agree with everything else you said but just one small clarification on this point. StabiliTrak and Traction Control faults won't prevent the cruise control from working. It's not listed in the disablers for the cruise in the troubleshooting guide, and the steering position sensor on my '07 has been throwing a Stab/TC light for a couple of years now and the TC still works fine.

Thanks for clarifying. Now that you mention it and that I think about it further, those times the CC wouldn't set and the TC and ST warnings must not have been directly related but both the results of a failure further up the chain. It's been too long for me to remember exactly what it was, but I recall it was a sensor issue.

To reinforce your clarification and dope slap myself, my TC and ST warnings are still on due to that dead rear speed sensor I haven't bothered to replace. My CC works fine.

 

[Geotrash]

Thanks for clarifying. Now that you mention it and that I think about it further, those times the CC wouldn't set and the TC and ST warnings must not have been directly related but both the results of a failure further up the chain. It's been too long for me to remember exactly what it was, but I recall it was a sensor issue.

To reinforce your clarification and dope slap myself, my TC and ST warnings are still on due to that dead rear speed sensor I haven't bothered to replace. My CC works fine.

Yeah, a misfire code would deactivate the CC, for sure. And I'm with ya - replacing that steering angle sensor isn't that hard, but it's just enough of a pain in the a$$ that I keep procrastinating about it.

 

[DaDenaliDude]

Brake light switch would be the first thing I’d try. When I bought my 07 Denali it wasn’t working and I replaced that part and it’s been working ever since. 20 minute job and the part is like $25.