grizzly67

2006 E55 AMG
Non-technical Newbie struggling with the red "Visit Workshop" battery light.
Have replaced the main battery in the rear.
Have replaced the 2nd battery under the hood.
Both show >12.5V when out of car.
When car is running, reading between rear main battery posts is near 14V.
I assume this eliminates the batteries and alternator as the issue?
No codes via reader, just the ugly red "Visit Workshop" light.
No noticeable performance, electrical or other issues.
Any ideas? What should I try next?

grizzly67

Maybe I should try this next?

https://mbworld.org/forums/w211-amg/...lternator.html

machild

With your reading of nearly 14volts at the battery the alternator and its voltage regulator are doing its job. If you are using a simple OBD II scan reader that is not going to tell you much about your car. Those scanners will only report engine operating faults - not any of the faluts from the many, many other computers throughout the car. You likely have an issue with the Battery Control Module (one of the many computers I referred to). Was the Red dash light showing before you replaced the two batteries?

grizzly67

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grizzly67

The red light appeared after the battery went completely dead. Put in 2 new batteries (front and rear) and red light remains. Do you know if that "Visit Workshop" light clears itself once the problem is fixed or does it stay on until cleared? For all I know, there is no longer a problem and the light is there from the previous event. I now have the regulator part 003-154-65-06 that's a simple change on the alternator, but I am reluctant to attack that as my hunch is the alternator is actually working. I will go with your advice and get a shop with an advanced scanner to read it but this is a logistic challenge too as the vehicle needs to be re-insured to drive it there (already stored for the winter).

machild

I suspect that the fault just needs to be cleared. I have not had that specific fault so I don't have any direct experience with it. Maybe someone else can share some light on this? Have you done a thorough search of the site to see if the issue does remain after correcting the low battery problem?

Fantomas

What he said, you need a decent scan tool to read the Auxilary Battery module and reset that code.

kevm14

I'll pile on because it's related - does anyone run AGM for the main battery and if so, is there anything to code for that? And can that be done with something like the iCarsoft?