Peugeot 607 Terminal 15 Ignition Problem

I had a similar issue with my old Opel Astra. Same symptoms - engine wouldn't crank, and the error codes pointed to a power supply issue. It turned out to be a corroded relay switch in the fuse box. Have you checked the relays? Also, give the wiring harness a good look-over for any signs of damage or loose connections. A voltage drop test might also help pinpoint the culprit.

Thanks! I'm not very experienced. Could you elaborate on the relay switch location and how to check it? Is a voltage drop test something I can do myself with basic tools, or should I get a professional?

On my Astra, the relays were in the main fuse box under the hood. I pulled each one out and checked for corrosion or damage on the terminals. For the voltage drop test, you'll need a multimeter, and it involves measuring the voltage at various points in the circuit while the engine is trying to start. If you're not comfortable with electrical diagnostics, it might be worth taking it to a workshop. Could save you a lot of time and potential headaches!

I've decided to take it to a workshop. The diagnosis confirmed a defective connection, and the repair cost 95€ and resolved the issue. Thanks for pointing me in the right direction!