marioeule1
C5 Overvoltage Errors
Summary of the thread
A 2004 Citroen C5 is experiencing overvoltage errors, with multiple system failures and a weak battery on startup. The suspected causes include a dead cell or short in the battery. A suggestion was made to check the alternator's voltage regulator, as its failure can lead to overvoltage issues. Ultimately, the problem was resolved by replacing the defective battery, which fixed the overvoltage errors and electrical instability.
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4 comment(s)
marioeule1 (community.author)
Thanks for the tip! Do you recall what symptoms you had exactly? Was it a difficult fix, or did you end up having to go to a workshop to replace the alternator?
horsthoffmann1
Yeah, the symptoms were pretty much the same: fault codes, weird system failures, and a flat battery. I tried a few things, but eventually, I had to take it to a workshop. Replacing the voltage regulator didn't solve the issue; the entire alternator was faulty. Best to get it professionally diagnosed.
marioeule1 (community.author)
You were spot on! Workshop confirmed it. The battery was heavily discharged and defective, causing the overvoltage. A new battery fixed everything! Repair cost me 290€ Thanks for pointing me in the right direction!
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CITROEN
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C5
horsthoffmann1
I had similar issues with my C5. Lots of weird electrical problems and overvoltage warnings, plus the battery kept dying. Check your alternator's voltage regulator; it's a common culprit. When the voltage regulator fails in the alternator, it can cause overvoltage, and damage sensitive electrical components.