Argo Cruise Control Failure

I had a similar cruise control issue with my 2019 Opel Astra, although the brand is completely different. Cruise control system relies on many components working in tandem. Have you checked the connections to the speed sensor? A faulty signal there can definitely disable the cruise control. Also, the pedal switch – that's the brake pedal switch, specifically – is a common culprit. Even a slightly misaligned or malfunctioning switch can prevent the cruise control from engaging. Make sure the switch is properly adjusted and functioning correctly. The error memory likely holds some clues!

Thanks for the advice. When you say 'connections to the speed sensor', are we talking about a simple continuity test, or is there more to it? I have a multimeter and I'm comfortable using it, but I don't want to start probing around randomly and risk damaging anything. Also, with the brake pedal switch, is there a specific resistance value I should be looking for? The service manual only offers general testing procedures.

Regarding the speed sensor, I suggest inspecting the wiring harness and connector for any signs of damage, corrosion, or loose connections first. A continuity test is a good starting point, but also check the voltage signal while the car is moving (safely, of course!). For the brake pedal switch, there isn't a specific resistance value per se. The switch is typically either open or closed. A diagnostic tool that can read live data from the switch would be ideal to confirm it's functioning as expected. At this point, unless you have access to specialized diagnostic equipment, I would advise to take your vehicle to a workshop.

I appreciate the input. Turns out, it was a corroded connector at the brake pedal switch. Cleaned it up, applied some dielectric grease, and the cruise control is back in action. The diagnostic tool at the workshop confirmed the repair. Total cost: 95€.