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 Marty Your Own Question

Marty
Marty, ASE Certified Technician
Category: Mercedes
Satisfied Customers: 53165
Experience:  Bosch Certified Master Technician with over 35 years experience in the automotive industry.
13230946
Type Your Mercedes Question Here...
Marty is online now

Sl55 amg electric consumer offline warning. has been an

Resolved Question:

sl55 amg electric consumer offline warning. has been an ongoing problem.large fuse replaced improved but didnt fix it.fault codes found and reset,no change. consumer battery showing a healthy 18.5volts with engine running so alternator not a problem. with engine off for two hours battery still shows 15.5volts which should be enough to run the systems however nearly all the systems have shut down until car is started [using starter battery]when systems start coming online again. after about an hour warning goes off and everything is fine until next day. i would suspect the battery is not holding charge but shows that it is [15 to 16 volts] the car seems to think there is not enough power to run the various systems so closes them down but there is enough AAAAAAARRRRRGGGHHH PLEASE CAN YOU HELP I do not want to start throwing ludicrously overpriced mercedes parts at this until i am sure what the problem is.
Submitted: 1 month ago.
Category: Mercedes
Expert:  Marty replied 1 month ago.

Hi, my name is ***** ***** is way too high. It sounds like you have a voltage regulator fault. You should get the vehicle scanned for fault codes with the Mercedes tester. More than likely you will find fault codes for excessive voltage, not undervoltage. You will probably need to replace the voltage regulator or alternator to remedy this problem.

Customer: replied 1 month ago.
ok but would this excess voltage cause the systems to go off. With 15 volts available after a short while with the engine off the doors wont unlock and there is barely enough juice to cancel the immobiliser
Customer: replied 1 month ago.
why wont this send
Expert:  Marty replied 1 month ago.

Overvoltage will cause the systems to shut down the same as undervoltage. What you are describing sounds like a weak battery though. What do you mean when you say there is barely enough juice? Is the rear battery going dead?

Customer: replied 1 month ago.
no the rear battery allways shows afull charge. by juice i meant that there is not enough power to run anything after a short period when the engine is off but the battery still shows a good charge. If the overcharging caused the systems to shut down why would they recover when the engine is running.However if you are sure there is too much charge then i will start with voltage regulator. I told this is a tricky one four engineers have failed to fix this problem
Expert:  Marty replied 1 month ago.

When an overvoltage situation occurs the system will shut down to protect them from damage. You need to get the voltage down to the proper range. 14.7V running is about as high as it should ever go.

Customer: replied 1 month ago.
ok thanks ill get the regulator changed and see what happens
Expert:  Marty replied 1 month ago.

You're quite welcome. Let me know if you need anything else.

Please remember to leave a rating for my service in order for the website to credit me for helping you.

Marty, ASE Certified Technician
Category: Mercedes
Satisfied Customers: 53165
Experience: Bosch Certified Master Technician with over 35 years experience in the automotive industry.
Marty and other Mercedes Specialists are ready to help you

What Customers are Saying:

 
 
 
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil
< Previous | Next >
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil
  • Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible. Charles
  • As a single woman, I really appreciate an excellent and affordable opinion.
    Thank you Geordie, I will not hesitate to contact justanswer in the future!
    Sue
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff. Jim
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C.
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex
 
 
 

Meet The Experts:

 
 
 
  • Matt

    Matt

    Mechanical Engineer

    Satisfied Customers:

    482
    BEng hons Mech engineering, in auto industry 22 years
< Last | Next >
  • http://ww2.justanswer.com/uploads/35/350matt/2012-6-7_182356_matsavatr.64x64.jpg Matt's Avatar

    Matt

    Mechanical Engineer

    Satisfied Customers:

    482
    BEng hons Mech engineering, in auto industry 22 years
  • http://ww2.justanswer.com/uploads/EU/eurotec/2012-6-11_13153_mpjaphoto.64x64.JPG Marty's Avatar

    Marty

    ASE Certified Technician

    Satisfied Customers:

    21371
    Bosch Certified Master Technician with over 35 years experience in the automotive industry.
  • http://ww2.justanswer.com/uploads/MI/mikeamechanic/2013-4-2_175558_photo.64x64.JPG mike_a_mechanic's Avatar

    mike_a_mechanic

    Mercedes Mechanic

    Satisfied Customers:

    116
    17 years experience as a auto mechanic, foreign and domestic.5 years running my own repair business.
  • http://ww2.justanswer.com/uploads/MB/MBpaul/2013-8-21_204936_paul.64x64.jpg MB Paul's Avatar

    MB Paul

    Mercedes Technician

    Satisfied Customers:

    212
    Mercedes Benz Qualified Diagnostic Technician
  • http://ww2.justanswer.com/uploads/IN/indytech/2013-8-8_102717_SantoDomingo146598x6402.64x64.jpg Greg's Avatar

    Greg

    Technician

    Satisfied Customers:

    1080
    Automotive diagnostic tech
  • http://ww2.justanswer.com/uploads/TE/techmachine/0601821347169_717372168_8940977_39623330_o.64x64.jpg Ross's Avatar

    Ross

    Diagnostic and repair technician

    Satisfied Customers:

    453
    Licensed diagnostic and repair technician