Another Red Battery message - help thread
Thread Starter
Member
Joined: Nov 2008
Posts: 132
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From: Columbus OH
A4, M3, 996, E55
Another Red Battery message - help thread
Guys, trying to clear up this issue up, hoping for a little help as it seems it could be many possibilities
I get the Red Battery / visit workshop message every time I start the car. Immediately on start up I get this message. The car never fails to start, doesn't crank slow, does not show any other messages and functions completely fine other than the warning message.
Car can sit for days and still start just fine.
Breaking out the volt meter tonight to diagnose further but where to start?
Aux battery (it's still the original)? is my gut but doesn't fall in line with others experiences here. IF we leave the car sit for like a week in the winter without driving I will get the convenience functions unavailable message which goes away pretty quickly. If it's daily driven we never get that message otherwise.
Thanks,
Andy
I get the Red Battery / visit workshop message every time I start the car. Immediately on start up I get this message. The car never fails to start, doesn't crank slow, does not show any other messages and functions completely fine other than the warning message.
Car can sit for days and still start just fine.
Breaking out the volt meter tonight to diagnose further but where to start?
Aux battery (it's still the original)? is my gut but doesn't fall in line with others experiences here. IF we leave the car sit for like a week in the winter without driving I will get the convenience functions unavailable message which goes away pretty quickly. If it's daily driven we never get that message otherwise.
Thanks,
Andy
Super Member
Joined: Nov 2009
Posts: 724
Likes: 31
Car free at the moment
This is indicative of the aux battery not holding charge. If you want to diagnose with the DVM, check the resting voltage on the aux battery before starting the car. I am not sure at what voltage the red error message is triggered, but anything below 12.25 volts is holding less than a 50% charge. You can google up a voltage vs. charge level graph for lead-acid batteries.
If the main battery is low you get slow crank and/or the convenience functions disabled message. A fast crank and start with immediate red battery message is the aux battery.
If the main battery is low you get slow crank and/or the convenience functions disabled message. A fast crank and start with immediate red battery message is the aux battery.
MBWorld Fanatic!
Joined: Jul 2012
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From: Canada
07 E63 + 07 CLK63CAB
If either battery is older than 5 years, replacement is not wasting money. A supposedly good battery will fail on the coldest morning or the hottest day or when you need the car the most. As the battery ages the alternator must work longer and harder to return the battery to top charge so while doing this the life expectancy of the charging system will be lowered. Also surges are more prominent on startup which will potentially cause other electrical gremlins, these cars like nice stable voltage.
Thread Starter
Member
Joined: Nov 2008
Posts: 132
Likes: 1
From: Columbus OH
A4, M3, 996, E55
Update. Volt meter tells the story I believe. Front battery reads only 7.5v at rest. Rear battery reads 12.8 at rest and 13.9 when running at idle.
Ordering aux battery tomorrow.
Ordering aux battery tomorrow.
Super Member
Joined: Jan 2010
Posts: 563
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From: The Villages, Florida
2006 E320 CDI
Those small batteries are something. I had my car at the dealer a couple of weeks ago and they performed a complete check of the car. They told me that the auxiliary battery is bad. Lucky, I had just purchased a AC Delco battery off of ebay about two months ago for like $38 and was waiting for a time to install it. I figure that both batteries are originals and are approximately seven years old. I have the old battery sitting on my bench for a couple of weeks now and the voltage will register anywhere from 10.34 to 11.60 volts. The voltage is weak, but it is still hanging in there.
Mike T.
Mike T.
Junior Member
Joined: Mar 2013
Posts: 35
Likes: 0
From: Mooresville, NC
Black 2005 E55
Andy, I had the exact same issue with the red warning light. It was the AUX battery. Changed out the battery, messages were cleared out, and no issues since the new battery. Good luck.
Senior Member
Joined: Apr 2013
Posts: 472
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From: Gainesville, FL: In a garage or in a bar, or a garage with a bar in it.
2005 E55, 2011 Honda Push Mower (21 inch deck bishes)
I had this exact issue a few months ago, and with a brand new battery in the trunk, I looked towards the front aux battery. Sure as can be, I replaced it and no more red dash...well, until I hooked my dual Aeroforces up and didn't wire a 12v lead to them thinking the OBDII port would power them..which it did......24/7 LOL.
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MBWorld Fanatic!
Joined: Jan 2009
Posts: 3,182
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From: Northern VA
W211
thought that was the problem with my 4matic. Replaced the aux battery, still had red death message and alternator, and a couple more messages. Replaced alternator as well and good to go.
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Thread Starter
Member
Joined: Nov 2008
Posts: 132
Likes: 1
From: Columbus OH
A4, M3, 996, E55
To update this thread on my resolution, in my case it was the Aux battery causing the issue. As stated above it was only reading 7.5v when the car was not running. Replaced Aux battery and no more warning lights.
Andy
Andy
