BigApe

Fellas,

All was going well on a sunny Saturday running errands. Go to get on the freeway and I romp on it and as I do, the radio shuts off, the red "visit workshop" pops up with the battery sign and a secondary message about the 'convenience features having been disabled' pops up.

I had just (2 weeks ago) put a new battery from O'reily's in it (760 CCA) so I shot down there to have them test it. They tested the battery at 100% but could not test the alternator as the tester could not get past some 'internal diod' code of the car.

Have any of you had experience with this happening? Doesn't sound good for my alternator

JEYVILLE

I had the same issue a month ago, it turn out to be the secondary battery.
Its located on the passenger side under hood,there a black cover below that is the battery. Have the voltage check on that one. $69 at sears

Hope this help!

xtc130iii

One of these.
Main battery, External battery, voltage regulator, alternator, battery control unit, external battery relay.

ripgut

it's your secondary battery in the engine compartment. don't spend $130 on an oem battery from the dealer, plus the deposit before returning the bad one. go to any battery store and buy an aftermarket one. i can't recall the size, but it should run you around $70-80. it's essentially a motorcycle battery and only takes a few minutes to remove/install.

sszgo

here is my situation with the voltage in the car

its a 2006 cls 55 amg


at idle does not charge, shows battery voltage
when i rev it up around 1500, voltage goes up to 14, 14.1 volts

while driving tends to stay around 14v, but as soon as rpms drop, seems to stop charging

any ideas?

neomaxmaya

it could be 2 things:
Your battery seems to be at its last days as its not holding charge consistently.
the battery regulator is faulty and not regulating charge to/from battery.
Worth to say, the meter fluctuates usually while revving the engine, but not like this though!.

Dat Carguy

The exact same thing happened to me last November. I was cruising on the highway and in a matter of 5 minutes i went from radio and massage seats to my headlights struggling to stay on with no power steering luckily home way the next exit. I had the same red screen "visit workshop" and stop immediately pop-up. It ended up being like everyone else has said the secondary battery which was shot along with my alternator, my main battery was still working just low on voltage so I only ended up replaced the secondary battery and alternator.

sszgo

most likely voltage regulator

scheduled workshop visit in few days, will see what happens