Cruise control cuts off abruptly

[koley5]

Driving down the highway at, say, 70 mph. Cruise control on. Everything's fine and then, after a half hour or so, it abruptly cuts off. I've discovered that if I turn the CC off and wait a few minutes, I can turn it on again and most times it will begin working. Or, I can pull over, turn the ignition off and on and enjoy CC again for awhile. Is this brake pedal related? Or what? The CC cuts off on it's own, not because I've touched the brake. I just thought I read somewhere that it was related to an old car and an old car's brake pedal. My car is a 2001 XC70 with 165,00 miles. Any help would be appreciated. It's not a life-altering problem, but I'm retired and like to take highway trips around the country. A working cruise control makes life much more enjoyable. Thanks.

[AKAMick]

Any ABS warnings when the cruise cuts out?

[koley5]

Thanks for replying. No, no warnings of any kind. I checked the codes and saw a 1237 code, but there was no CEL or anything. I cleared the code.

[tmcmilli]

When you say it cuts off, does the Cruise indicator on the gauge cluster disappear? Or does cruise control simply stop controlling your speed as if you had tapped the break pedal, with the Cruise indicator remaining on? And if the Cruise indicator is staying on, it will not resume if you press the resume button, correct?

[BillAileo]

According to a posting elsewhere code P1237 indicates a problem with your turbo control valve and that it's either malfunctioning due to old age or one of your vacuum lines has disconnected and is giving false readings. I don't know how accurate that is.

[koley5]

Thank you. The Cruise indicator stays on and simply stops controlling my speed as though I had tapped the brake pedal (which I have not done). It will not resume until I either shut off Cruise and the re-turn it on again, or if I shut off the ignition and re-start it.
Yes, I'm aware that the 1237 code has to do with the Turbo Boost Control valve.

[albertj]

I'd check to see if I had a vac line accidentally disconnected during other service. This may or may not help: https://www.matthewsvolvosite.com/ho...-tcv-work.html

Albertj

[Thang Vora]

Check the speed sensors at all four corners in the wheel hubs.

[AKAMick]

Check for cracked and corroded tone rings if in a rust belt state. also this thread is Zombie, past its sell by date.