How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Pete Your Own Question
Pete, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 27862
Experience:  Over 15 years experience as a Mercedes dealer technician
Type Your Mercedes Question Here...
Pete is online now
A new question is answered every 9 seconds

I have MB SL 350 year 2006 and the battery warning light is

Customer Question

Hello! I have MB SL 350 year 2006 and the battery warning light is on and visit workshop. On the diagnostic tool we got three codes under eloctronic stability programe (6210 abs control system, 6230 esp operation, 5B13 test battery control module). These codes are parmanent and cannot be deleted. When the engine is on the voltage on both batteries is around 14V. We are assuming battery control module in the rear right side of the trunk, but how to be sure? Thank you
JA: Just to clarify, what are the exact lights you're talking about?
Customer: just for the battery (red one)
JA: Are you fixing your SL yourself? What have you tried so far?
Customer: we checked both batteries and all the fuses, measure the voltage on both batteries, do the diagnostic...
JA: Anything else you want the mechanic to know before I connect you?
Customer: Is there any wiring scheme (voltage input or output) of N82 (battery module) that i can check to see if N82 is bad?
Submitted: 7 months ago.
Category: Mercedes
Expert:  Pete replied 7 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Did you have the batteries actually tested at all?They may have the correct voltage but may be weak or low on amperage causing this issue here.I have seen this before and had to replace the affected battery.I have also seen where the alternator will not charge properly or sufficiently and cause this as well and this should be tested.Usually if your at 14 volts all of the time the alternator is trying to recharge a weak battery.This is common with a battery needing replaced.

I would have the batteries and alternators properly tested (usually a local parts store can test these at no charge to you) and if found to be o.k. with all of these then the battery control module needs replaced.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete