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I drive a C350e 2018 (plug in hybrid). Since yesterday i have an error when starting the car: Auxiliary Battery Malfunction Since then it also seems the electric motor is almost not used at all while driving. And in driving modes the E-drive option is greyed out. Start and stop feature also does not work. Car ignites the petrol engine when turned on even when e-drive battery is full.
Is the electric motor operation issue related to the Auxillary Battery issue? Is it normal that an Auxiliary Battery dies after 18,000km?
Hi,
Auxillary batter Malfunction will display when your part paul capacitor on passenger side under glove box goes bad there is no auxiliary batter in mercedes c300 2015 w204 cars. Injust replaced with dealer parts is $154.81 Labor $257.37 approx $412.57. You can drive you car without fixing but for me it annoying so I fixed it. This job you can dyi but I wanted the dealer to xenry , diagnostic my car also I replaced crank valve p052e71 code which costs around $1750 .
C350e with Comand, Vision Package and seat package, 2017 Mini Cooper S 7
I've just replaced the Auxiliary Battery on my C350e after 17,000 kms (3.7 years old).
Apparently this is a common fault with the W205.
However, be aware that the Auxiliary Battery for a Hybrid car is different to the Capacitor type battery on the standard car. It is, in fact, a mini acid type battery.
I had mine replaced by Mercedes for AUD 635.
I've just replaced the Auxiliary Battery on my C350e after 17,000 kms (3.7 years old).
Apparently this is a common fault with the W205.
However, be aware that the Auxiliary Battery for a Hybrid car is different to the Capacitor type battery on the standard car. It is, in fact, a mini acid type battery.
I had mine replaced by Mercedes for AUD 635.
So as a precaution I went in and disassembled the foot well to test the aux battery which did turn out to be a whole other AGM battery. It tested fine, here is a pic of the top sticker. My issue turned out to be the main 12v AGM battery, replaced it and the emode reactivated.
Hi guys… the 12v in my 2016 C350e needs to be replaced and the local dealership is quoting ~$1000US to do it. The majority of that cost must be the labor. Anyway, when they went to perform the replacement they said a tie-down or hold-down strap was missing so they couldn’t (wouldn’t?) do it until they order and receive that from Germany. I was shocked to hear about the strap to begin with because it seems to me that the way the battery is situated in the trunk/boot it could not possibly move. Any thoughts on whether or not this “missing” strap is actually necessary??
Originally Posted by charlzie88
So as a precaution I went in and disassembled the foot well to test the aux battery which did turn out to be a whole other AGM battery. It tested fine, here is a pic of the top sticker. My issue turned out to be the main 12v AGM battery, replaced it and the emode reactivated.
Battery tie-downs hardly go flying to the point of getting lost. Perhaps this is using a short tie-down by the base.
Is there a way you can produce couple good pictures of your trouble battery showing the base in particular??
$1000 battery quote :
Sounds more like the $200 starter 12V battery rather than the tiny $100 Aux.
Last edited by CaliBenzDriver; 02-27-2022 at 02:53 PM.
The main starter battery sits in a tray in the trunk with the hybrid battery cross member running directly over it, even if the metal tiedown is missing its unlikely the battery will move based on the weight and the position of the battery. Here's a video of the process, the tie down can be seen at 3:07
If this is the Aux battery, that actually sits in a snug enclosure in the foot well and I don't believe there is an actual tie down but the same thing can be said, it is unlikely it will shift or move.
Hi guys… the 12v in my 2016 C350e needs to be replaced and the local dealership is quoting ~$1000US to do it. The majority of that cost must be the labor.
No - the majority of that must be profit. I stopped relying on dealer service departments 20 years ago when a service manager told me it would take a week to order and receive a grade 8 engine mount bolt. I drove down the street and bought one at True Value for 49 cents. Still annoys me I have to visit MB service depts for recalls.