Malfunction of auxiliary battery
Asked by louie2452 Jun 27, 2018 at 11:48 AM about the 2015 Mercedes-Benz E-Class E 350 Sedan RWD
Question type: Maintenance & Repair
I have an error that states that the auxiliary battery malfunction. What is the risk
for a failing auxiliary battery. Please explain just what the reason my car has an
auxiliary battery. I have asked the dealer but the dealer does't know.
2 Answers
Hornet_2497 answered 5 years ago
I am not familiar with your vehicle but I am guessing that having two batteries means it has a diesel engine rather than a gasoline engine. The reason is diesel engines are higher compression and are harder to crank over and need more battery power (higher CCA rating). They often have glow plugs too. Okay, if one of the two batteries is failing, it will drag down and kill the good battery. Have both of them tested separately and replace the weak one. Some mechanics might recommend replacing both at the same time so they are equal in all ways. That makes sense.
I do not have a diesel engine in my 2011 E 350 . Do I need to replace my battery?