Volvo S40 Terminal 15 Ignition Error

Hey there, that sounds familiar! I had a similar problem with my old Opel Astra, though it was a petrol version. The car would just randomly refuse to start, and the error codes pointed to some kind of power supply issue. Did you check the main earth points in the engine bay and near the battery? They can get corroded and cause all sorts of weird electrical gremlins.

Thanks for the tip! I'll definitely give the earth points a look. When you say main earth points, are you referring to the ones that connect the engine block and chassis to the negative terminal of the battery? And did your Astra also throw the exact same error message about terminal 15 being interrupted?

Yep, exactly those earth points. Give them a good clean with some sandpaper and contact cleaner. As for the exact error message, I can't recall the precise wording, but it definitely indicated a problem with the power supply to the ignition system. If cleaning the earth points doesn't work, honestly, I'd take it to a workshop. Electrical issues can be a real pain to diagnose without the right tools.

Thanks a lot for sharing your experience! It was indeed a defective cable. I brought the car to a trusted workshop, they replaced the faulty wiring, and it cost me 95€. Now my old Volvo runs smoothly again.