Dynasty Overvoltage Electrical Issue

Indeed, a heavily discharged or defective battery could very well be the culprit behind the overvoltage errors and system failures you're observing. Modern vehicle electrical systems are intricately interconnected, and the battery serves not only as a power source but also as a voltage stabilizer. When a battery is severely depleted or failing, it can no longer effectively dampen voltage spikes and fluctuations generated by the alternator. These uncontrolled voltage surges can then trigger overvoltage detection by the vehicle's electronic control units (ECUs), leading to fault codes and system malfunctions. Before condemning the alternator or other components, have the battery properly load tested to ascertain its condition. Also, check the battery terminals and connections for corrosion and tightness, as these can contribute to voltage irregularities. What voltage readings are you observing when the engine is running?

Thank you for the detailed explanation. That makes a lot of sense. I don't have the equipment to measure the voltage myself while the engine is running. I'm not sure I understand the intricacies of modern vehicle electrics well enough to diagnose this myself anyway. Is it likely that the alternator is damaged as a consequence of this?

It is certainly possible that the alternator has sustained damage due to being forced to work harder to compensate for a failing battery. Over time, this increased load can lead to premature wear or failure of the alternator's voltage regulator. However, it's also possible that the alternator is still functioning correctly and the overvoltage is solely attributable to the battery's inability to buffer voltage fluctuations. Given the complexity of the issue and your lack of diagnostic equipment, I would strongly advise taking the vehicle to a qualified workshop. They can perform a comprehensive electrical system diagnosis, including battery load testing, alternator output testing, and voltage drop testing, to pinpoint the root cause of the problem and prevent further damage. Replacing parts without proper diagnosis could be costly and ineffective.

I appreciate the advice. I took it to a local workshop, and after their diagnosis, they confirmed that the battery was defective and had indeed put a strain on the alternator. The final repair cost was 290€, including a new battery and testing the alternator. Thanks again for your help!