Hello. A while back both Cruise Control and Parking Break Stopped Working, at the same time on my 2008 V70. I can turn on the cruise control button on steering wheel, the cruise icon lights up on in the dash, but the cruise system does not engage or function. The indicator for cruise turns off when you turn off the steering wheel button too. Simultaneously, the electronic parking brake system has stopped working too. It does not turn on or any indicator lights coming on/off either. I do get the error messages on the dash, Parking Brake Service Required, and Park Assist System Service Required, which has not worked for a while either. I can turn on the park assist sensors switch on, it stays on for a brief second and then shuts off (assuming a short or grouding issue somewhere among the eight sensors).
The fuses are fine and of appropriate amps.
Any thoughts and repair ideas are greatly appreciated. Of all of these the cruise control is the most needed feature when driving this car, as the others can be mitigated otherwise.
Thank you all in advance. Be well.

 

have you looked at a wiring diagram to look for any common circuit paths and ground points? I'd be looking for a damaged connector etc (possibly under the car?)

 

I am by no means a mechanic but I bought a 2008 V70 with 75k on it. Driving home from Atlanta to Indy my cruise didn't work. I also got a Parking Brake error. When home I mistakenly engaged the parking brake to see if I could clear error and I managed to lock the back wheels and had to have it towed. Turns out my mechanic said the cruise is hooked in to parking brake system. I had my mechanic just disable the parking brake (Indiana is very flat) because it was going to take buying a new circuit board and having Volvo reprogram it which my local dealer will not work on any Volvos over 10 years old!!!

 

My 2005 V70 R has a manual transmission and manual hand brake. However, he car requires the driver to engage the clutch to start the engine. At one point ~10 years ago, the clutch-in to start feature stopped working, and as I recall, the cruise control went out at the same time. My Volvo guy found a bad sensor for the clutch. He replaced that and the cruise also came back on line. It's been fine ever since. Your diagnosis will be different with an AT and E-brake, but the answer is likely in a similar sensor. RE your mechanic search - I had the same issue. My guy was a 30-year Volvo veteran who moved from a dealership to his own shop. Unfortunely he died during COVID. My new place has the same 10-year policy but agreed to service my 2005 because I became an existing customer with my wife's 2021 Volvo.

 

Good point about the clutch - I'd expect that pressing in the clutch should also disengage the cruise so it makes sense that its position sensor (as well as the brakes) is tied to the cruise. Same with the ebrake.