Citroen C3 Undervoltage Error

I encountered a similar problem with my C3. The sluggish starts and electrical issues point to the battery. Did you load test the battery? What's the voltage at rest and during cranking? A voltage drop during cranking suggests a failing battery, even if the resting voltage seems adequate.

I haven't done a formal load test yet, but the resting voltage was 12.4V. During cranking, it dropped to 9.8V, which does suggest a compromised battery. What was the resolution in your situation? Did a battery replacement fix it, or were there other complications like charging system issues?

In my case, the voltage drop during cranking was due to a defective battery. Replacing it fixed the issue. Given your numbers, a similar outcome is likely. Still, get a diagnostic assessment at a workshop to rule out alternator or voltage regulator problems. It's a good idea, considering potential electrical failures.

Following your advice, I replaced the battery, costing 290€. The undervoltage error is gone, and all symptoms are resolved. Your suggestion about charging system issues was good, as I'll monitor the charging voltage to ensure no hidden problems exist. Your expertise was invaluable.