LexBrett2

Hi All, I just purchased a 2003 sl500 from a friend and had the sbc brakes repaired for free under warranty. I have not been able to register the car due to covid 19 so have not driven much (submitted forms in the mail). So I have not been driving, and just starting her occasionally, and detailed the car all week with the door open for a few minutes which I know can draw down the battery.

The worst possible thing happened last night. I went to start the car, and the esp light came on, the radiator fan went crazy, and some other warning lights. and I turned off the car and now it won't start. The key turns but there is no crank. Thinking it was a low starter battery, I tried to jumpstart and trickle charge overnight to no avail.

My icarsoft mb2 reader says something about general communication failure with the sam/canbus. It does not make any sense at all?!

My plan is to look more closely at the battery, call the dealer who did sbc repairs, and check every fuse in the car.

Does anyone have suggestions? Pleas help!!

MikeJ65

Did you check/charge the consumer battery in the trunk?

LexBrett2

yep

Aussiesuede

Try disconnecting both batteries for 5 minutes. Then reconnect just the starter battery under the hood and leave the consumer battery in the trunk disconnected. Turn the key and all of the warning lights should illuminate. Try to start the vehicle. After it starts, then reconnect the consumer battery in the trunk. BCM should then be resyncronized.