Mercedes R Klasse Diesel auxiliary battery problem

I had a similar issue with my R Klasse Error messages all over the place especially during engine start Turned out to be low voltage on the auxiliary battery Have you checked the battery's voltage with a multimeter Also make sure the connections are clean and tight A faulty voltage regulator could also prevent the battery from charging properly Was it just the error message or did you also experience difficulty starting

Thanks for your reply I haven't checked the voltage with a multimeter yet but I will The connections look fine at first glance but I'll double-check them Besides the error message the engine start is sometimes weak and some other electrical systems seem to be acting up Could you elaborate on your experience Was it definitely the auxiliary battery causing all the problems

Yep for me it was definitely the auxiliary battery Exact same symptoms error messages weak engine start the whole shebang I tried cleaning the connections but it didn't help Ended up taking it to a workshop They confirmed it was the auxiliary battery not holding a charge Replacing it fixed everything I suggest you do the same especially if you are getting low voltage readings

Thank you for sharing your experience It seems like a battery replacement is the most likely solution I checked the voltage of the auxiliary battery and it was indeed low I've booked an appointment with a workshop to get the battery replaced Hopefully this will resolve the battery malfunction and the other electrical issues I've been experiencing