So this appeared on my SL500. Anybody have any idea what it means? It disappears after I scroll through the menu, but leaves a malfunction message in memory. I plan to take it to the dealer but would like a clue as to what it might be before I take it in. It occurred after the car had been sitting for a few weeks. At first I thought it might be the alternator, but the batteries seem to be charged. I took it for an extended drive and no other problems occured. Both batteries are new within the last two years.

 

This means that the voltage in your car has dropped below a safe threshold. It could be that the rear (consumer) battery is bad and needs to be replaced, or that it has simply discharged due to lack of use, or that you have a bad alternator, or a problem with the BCM (battery control module). The reason this is a red (severe) error is that low voltage can cause the SBC brake system to malfunction, leaving you with very limit braking. You need to get this diagnosed and fixed ASAP.

 

I appreciate your explanation. Thanks!