Datsun_76

Need some advice on where I should start troubleshooting.

I have a 2006 CLS55 AMG. It is currently -10 F outside and my car does not want to start. It will crank but not turn over. My battery voltage is a bit low at 11.9 volts when the car is off. If I can get it to finally turn over (most days it won't start) the voltage is 13.9 and I get the "low battery conven functions temporarily unavailable" error for a few minutes. If I leave the battery on a tender that car will start up without issue. The car only has this issue when the temperature is below 15 F. Anything warmer than 15 F and it starts beautifully.

I replaced my alternator, crank position sensor, starter, and both batteries over the summer. I have had both batteries tested multiple times at different places and they are good.

I am not sure where to start troubleshooting from here. Could there be a parasitic draw? Should I get a better battery designed for cold weather? I do not think it is fuel related. I have good pressure at the rails.

Any suggestions/input would be appreciated. Thanks!

Datsun_76

Anyone?

machild

You will get much more eyeballs looking at your posts if you posts in the E55 forum. As you likely know, the CLS55 is basically identical mechanically to the E55 of the same year but there were a lot more E55's than CLS55. To get to that page go here: https://mbworld.org/forums/w211-amg-81/