Hello32

Hi all, Every time I turn my car off or open the door i get this message with a yellow battery indicator. I just replaced the battery last month, does anyone know what the problem could be? i have heard this model does not carry a luxuary battery. Its a 2015 c300 w205. thank you

Andy74

Battery is weak. I replaced my battery last month also but i i dont drive my car much. Sometimes i get the same message. I think the battery is to small or there is a leak of power when the car is off. I will see an electrian.

Hello32

I took the car to autozone and he checked the battery and said was fine. Ive read somewhere their is a module in this model that takes place of auxiliary battery, that might need to be replaced

Andy74

I also changed my auxiliary battery when i saw auxiliary battery malfunction on my dashboard. I am not sure why its diying so soon. Is it normal for a battery to die because the car has not been driven for a week. There must be a leak somewhere something that is still running when the car is off. I will let you know if I find something.

Ron P Baker

This is the warning message you see when the auxiliary "battery" malfunctions, it is not the warning you describe:



More on "Auxiliary Battery Malfunction" warning and its components:

https://mbworld.org/forums/c-class-w...lfunction.html

Hello32

sorry didnt releize this was a n old thread,

fred9x

I had not been driving my GLC for weeks and when I got in to drive it, I got the message/icon that is the 3rd one down on the attached. I interpret it to mean the battery needs to be driven some to charge the battery.

Hello32

Anyone know how to properly diagnose if this issue is caused by a faulty voltage converter? I was having this issue last year and I installed a new battery from auto zone and the issue went away. Now it has came back after a year, so i ordered a voltage converter from amazon and plan on replacing it later this week. Just wondering if anyone knows how I would diagnose this properly, The light says Stop Vehicle, Shift to P, leave engine running. After doing some research, This could either be my main battery, the voltage converter or my alternator. Sometimes I am able to turn the car off and the light will go away and other times it will stay on. the voltage converter i bought is

MitchellC

Start Engine. See Owner's Manual solved

There is a service bulletin published for this and it is a £0 fix.

This also prevents the Stop/Start from working. "W205 Stop/Start not functioning"

Symptom - Yellow battery symbol fault message in multifunction display "Start Engine. See Owner's Manual" is caused by battery sensor detecting battery resistance of 8 mΩ and above.

Cause - The cause could be an internal resistance problem with the battery but in the case of the common issue reported by the bulletin the cause is: - Excess hot melt adhesive from the heat-shrinkable tube on the cable lug of the measurement line (0.75 mm²) from the on-board electrical system battery G1 (main 12v Battery) to the battery sensor B95 leads to an increase in the internal resistance of the battery. Due to the detected high battery internal resistance (caused by the hot glue), the yellow fault message generated in the multifunction display.

Bulletin, including pictures how to fix are here: MC-10134790-9999.pdf (nhtsa.gov)

Also check ODB2 Codes - Use ODB2 reader to confirm fault code "B1F4500" in the driver side SAM module.
Also check ODB2 real-time data - Use ODB2 reader to view data in driver side front SAM module - check the Stop/Start function data, this lists all the reasons why Stop/Start is inactive - "Battery Condition preventing Stop/Start from operating" will be set to "Active"

Hope this helps

Hello32

I ended up changing the auxiliary battery and it fixed it.