Volvo V40 Terminal 30 Power Interruption

Ah, Terminal 30 issues on a Volvo, sounds familiar! I had something similar with my V40 (petrol too). Cranking was a nightmare, especially in the cold. Did you check the circuit breaker? I had a corroded connection there once; caused all sorts of mayhem with the power supply. Check the wiring harness too, especially near the starter motor!

Thanks for the insights. Could you say where the circuit breaker you checked is? Was the corrosion obvious, or did you need to examine the wiring harness more closely?

Yeah, it was a pain. The breaker was near the main fuse box, under the hood. I didn't see the corrosion at first glance. I had to wiggle the wires and then saw the green crusties. Honestly, after messing with it, I just took it to a shop. They confirmed my suspicion and sorted it out. You might want to consider doing the same if you're not comfortable digging deep into the electrical system.

I appreciate the confirmation and recommendation. I took it to a certified Volvo technician. The diagnosis matched our assessment: a defective battery and corroded wiring leading to the circuit breaker. The repair, including parts and labor, cost 290€ Thank you for steering me towards a quick fix.