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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4959
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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It lit up a warning light that says: "Alternate battery Low"

Customer Question

It lit up a warning light that says: "Alternate battery Low"
JA: How old is the battery? And have you tested it with a voltmeter?
Customer: No car is 2015 C300. Think it has the battery from new
JA: Are you fixing your C300 yourself? What have you tried so far?
Customer: No. It is a used car just bought
JA: Anything else you want the mechanic to know before I connect you?
Customer: When waiting in traffic light for long a A green light lit up (Eco) and then hit something an get steady
Submitted: 4 months ago.
Category: Mercedes
Expert:  Lou P. master tech replied 4 months ago.

Hello, my name is***** and i will do my best to assist you.I am going over your story now and will reply back soon with some info,thanks!

Expert:  Lou P. master tech replied 4 months ago.

with the eco start stop you have a auxiliary battery , the battery will need checked along with the battery sensor, either the battery is weak or the battery sensor is faulty and reading the wrong voltage to the control units, this can only be checked with a mercedes scan tool so its best to take to a dealer for this because the independent shops do not have knowledge of this style of system yet,

please let me know if there is any additional info you need, I am here to help,

Please take a second and click the stars at the top of the screen to rate me so i may receive my credit , 5 stars is ideal , please request me in the future.Keep in mind then when you rate it does not end our conversation, you can still return here to me for follow up information if needed just simply reply back, thanks!
Lou P.
Master Mercedes-Benz Technician
Master ASE Certified