robin_frank63
V40 Auxiliary Battery Error
Summary of the thread
A 2017 Volvo V40 diesel with 204,394 km is experiencing an auxiliary battery error message and related fault code, accompanied by weak engine starts and electrical malfunctions like flickering interior lights. The suspected cause is the auxiliary battery not charging properly. A similar issue in another vehicle was resolved by replacing a dead auxiliary battery, suggesting that testing and potentially replacing the battery could resolve the problem. After taking the car to a shop, the auxiliary battery was confirmed as the issue and replaced, resolving the errors and improving engine start performance.
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4 comment(s)
robin_frank63 (community.author)
Thanks for the quick reply! I haven't checked the voltage while the engine is running, but I did check it when the car was off, and it seemed a bit low. What was the eventual cause in your case with the BMW?
michael_schwarz1
Turned out to be a dead auxiliary battery. Voltage drop was causing all sorts of weirdness. If your voltage is low even when off, it's probably toast. Best bet is to get it tested properly at a workshop. Save yourself the headache.
robin_frank63 (community.author)
Thanks for the advice! I took it to a local shop, and you were spot on. The auxiliary battery was indeed the culprit. They replaced it for 290€, and all the errors are gone. Starts like a charm now. Appreciate the help!
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VOLVO
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V40
michael_schwarz1
Sounds familiar. Had a similar gremlin with my BMW 3 series. Auxiliary battery kept throwing errors. Symptoms were like a weak circulatory system in a human body. Have you checked the voltage across the battery terminals when the engine is running? Could be a faulty alternator not topping it up.