USMCR O-5

Lately I've been getting the message in the photo below, "Low Battery, Convenience Functions Temporarily Unavailable." Along with that, the dashboard clock keeps adjusting its time. Could it be as simple as needing a new battery? And if so, which one? The car starts and runs fine, but I understand that there is a second battery in the engine compartment. Is that battery for accessories? Right now, I don't have the Comand Unit to include radio, navigation and satellite. Thanks.

mersum1es

Message is due to main battery low voltage. Either real one or false readings due to bad grounding or contact. When the message appears? If right after start, you may have drain current (should be under 60mA when car at sleep mode). If coming while driving alternator/voltage regulator may be faulty. Or battery just bad, cannot keep or receive charge.

Measure battery voltage, again when engine running. Measure drain current. Check all lead contacts near the battery.

Some related reading here:
http://www.benzworld.org/forums/w211...ule-fault.html

Plutoe

Yep the battery control module has sensed the poor quality of the battery------if you turn on either your heated seats or rear defroster---do the light switches blink??

Regardless, have the system, not just the battery, checked out!!