Conflicting reports from dealership and Good Year. Which one to trust
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2020 gls 450
Conflicting reports from dealership and Good Year. Which one to trust
Hello.
I just bought a 2020 GLS from Carmax and got it checked at a local MB dealership.
The report came back with the rear brake and battery need to be replaced.
I brought the car back to Carmax and they asked me to take it to Good Year for a second opinion.
The report from Good Year said that the rear brake indeed needs to be replaced, but the battery is still good and does not need to be replaced.
Below is the details about the battery from dealership report:
+ "Battery has high resistance and failed test"
+ "Has current codes in front SAM and EIS for no- load current off output switch has a malfunction" -> "may need a battery, will have to diagnose" (Could anyone please explain what this means and why they want to charge $1017.89 to diagnose when changing the battery cost $650?)
I would like to ask for your opinions which report should I trust in this case. Did the dealership try to upsell or they used a higher standard preventive check, or maybe Good Year just did not check properly?
Thank you so much!
I just bought a 2020 GLS from Carmax and got it checked at a local MB dealership.
The report came back with the rear brake and battery need to be replaced.
I brought the car back to Carmax and they asked me to take it to Good Year for a second opinion.
The report from Good Year said that the rear brake indeed needs to be replaced, but the battery is still good and does not need to be replaced.
Below is the details about the battery from dealership report:
+ "Battery has high resistance and failed test"
+ "Has current codes in front SAM and EIS for no- load current off output switch has a malfunction" -> "may need a battery, will have to diagnose" (Could anyone please explain what this means and why they want to charge $1017.89 to diagnose when changing the battery cost $650?)
I would like to ask for your opinions which report should I trust in this case. Did the dealership try to upsell or they used a higher standard preventive check, or maybe Good Year just did not check properly?
Thank you so much!
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Current/Last 5-years:GLS;G70;Alpina B8;X7;Accord. Sold:X7,TeslaS;S560;S550,X5;530e;L.Navigator;LS460
Mbenz has the right tool to look into the errors and battery health condition. I’d say just buy a new battery for $650 and let Carmax install it. Alternatively, it sounds like Mbenz should have cleared the errors first, let you drive the car for a few days, and then re-do the diagnosis to see if the errors will show up again. Note that new Mbenz cars with the 48V system don’t like anything less than 100% healthy 12V battery. That will cause all kind of glitches for a minor issue like this, all cause of that low voltage battery.
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From: Tennessee
2015 MB S550 & 2020 MB GLS 450
While I can't address your situation, I still have the original battery in my 2020. Last year I received an email from my dealer with an offer of a new 12v battery for $463. Sent my SA an email about it given the price, and he advised me to wait saying I likely still had a year or two on the current battery. I've had no issues. I just looked on the dealer's website and they still have the battery offer. If you still have the original battery and are concerned, I would check your dealer's website for Service coupons and see if there is one for the battery. I would just have the battery replaced and not consider their diagnosis, with the additional fee. If you have the original battery, it won't be long until it will need to be replaced.
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2020 gls 450
Thank you for your responses.
In the report from Good Year that considered the battery as good, the battery's at 86% health (and most likely be the original one).
I will schedule with the dealership to have it replaced.
Again, really appreciate your advice.
In the report from Good Year that considered the battery as good, the battery's at 86% health (and most likely be the original one).
I will schedule with the dealership to have it replaced.
Again, really appreciate your advice.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
While I can't address your situation, I still have the original battery in my 2020. Last year I received an email from my dealer with an offer of a new 12v battery for $463. Sent my SA an email about it given the price, and he advised me to wait saying I likely still had a year or two on the current battery. I've had no issues. I just looked on the dealer's website and they still have the battery offer. If you still have the original battery and are concerned, I would check your dealer's website for Service coupons and see if there is one for the battery. I would just have the battery replaced and not consider their diagnosis, with the additional fee. If you have the original battery, it won't be long until it will need to be replaced.
I usually get 7 - 9 years out of my OE batteries. I put them on maintainers every month or so, or when I won't be driving it for a week or more.
There are a lot of phantom draws when the car is waiting for or receiving data. Or you walk by with a key. Or your app queries.
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W213 All-terrain
Also, the 'health" measured by a generic workshop it's just a generic advice The MB dealer read data inside of your car SAM ( Signal Acquisition Module ) which is the real data based on many parameters that none generic workshops can read.
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2020 gls 450
On the Negative terminal you can see the production date something like 22/20 where the 22 is the week and the 20 is the year
Also, the 'health" measured by a generic workshop it's just a generic advice The MB dealer read data inside of your car SAM ( Signal Acquisition Module ) which is the real data based on many parameters that none generic workshops can read.
Also, the 'health" measured by a generic workshop it's just a generic advice The MB dealer read data inside of your car SAM ( Signal Acquisition Module ) which is the real data based on many parameters that none generic workshops can read.
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GLE 580
Did that include labor?
I usually get 7 - 9 years out of my OE batteries. I put them on maintainers every month or so, or when I won't be driving it for a week or more.
There are a lot of phantom draws when the car is waiting for or receiving data. Or you walk by with a key. Or your app queries.
I usually get 7 - 9 years out of my OE batteries. I put them on maintainers every month or so, or when I won't be driving it for a week or more.
There are a lot of phantom draws when the car is waiting for or receiving data. Or you walk by with a key. Or your app queries.
Last edited by wildta; Sep 21, 2025 at 02:08 PM.
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Senior Member
Joined: May 2019
Posts: 330
Likes: 119
From: Tennessee
2015 MB S550 & 2020 MB GLS 450
Did that include labor?
I usually get 7 - 9 years out of my OE batteries. I put them on maintainers every month or so, or when I won't be driving it for a week or more.
There are a lot of phantom draws when the car is waiting for or receiving data. Or you walk by with a key. Or your app queries.
I usually get 7 - 9 years out of my OE batteries. I put them on maintainers every month or so, or when I won't be driving it for a week or more.
There are a lot of phantom draws when the car is waiting for or receiving data. Or you walk by with a key. Or your app queries.
