Peugeot 4007 power steering fault

Sounds like a power steering issue. Vibrating wheel and spongy handling are classic symptoms. Wheel alignment can contribute, but usually not that drastically or suddenly. Since you have an error code, the system is detecting a fault. Before assuming it's the steering rack or pump, have you checked the cable and plug connections to the power steering components? A loose or corroded connection can cause electrical issues.

Thanks. I haven't checked the cable and plug connections yet. Where exactly should I be looking for these connections? Are they easily accessible, or do I need special tools?

Locating those connections can be tricky. Start with the power steering pump and trace the wiring harness. The connections are usually secured with clips or plugs. Check for any signs of corrosion, damage to the wires, or loose connections. A multimeter can be helpful to test for continuity. If you're not comfortable working with electrical systems, it’s best to leave it to a professional. Given the stored error code, a workshop visit might be best.

Thanks for the advice. I took it to a workshop, and you were spot on – it was a defective plug connection, now repaired. The total cost was 95€! I appreciate your help!