Mercedes Used Warranty, Stop Start still not working after new Mercedes Battery

[TW666]

I have an Approved Used C Class still under warranty. It has a new Mercedes battery and yet the Stop Start still does not work, it shows a crossed through amber icon. To ensure the new battery was fully charged I connected a Ctek mxs 5.0 charger to it for 24 hours, the Ctek completed its cycle and the car voltage showed 12.46 volts (whilst connected). I’ve allowed time for the engine and transmission to reach normal operating temperature although it has been a cold morning outside.
Does this sound like a fault or am I missing something ? I’m aware Stop Start can be very sensitive to battery voltage/ temperature etc.
I intend to ask my dealer to check if there is a fault somewhere and if it’s covered under the Mercedes used car warranty.
Any comments appreciated.

 

[MeQ]

Which battery did you check/charge?

 

[TW666]

Which battery did you check/charge?

I charged/checked the starter battery voltage, I think I may have a capacitor instead of a second battery in a 2020 facelift C Class.

 

[rf065]

I charged/checked the starter battery voltage, I think I may have a capacitor instead of a second battery in a 2020 facelift C Class.

Mine has the capacitor, 2016 model, I've had both that and main battery replaced as stop start was not working.

 

[TW666]

Mine has the capacitor, 2016 model, I've had both that and main battery replaced as stop start was not working.

Ok thanks, sounds like I need to get the capacitor replaced too.

 

[BTB 500]

It has a new Mercedes battery and yet the Stop Start still does not work, it shows a crossed through amber icon.

Presumably you've seen the list of conditions in the handbook (this is for my 2019 non-AMG car):

I intend to ask my dealer to check if there is a fault somewhere and if it’s covered under the Mercedes used car warranty.

I would drive the car normally for a few days and if stop/start never becomes active (bearing in mind the above criteria) then simply ask them to fix it. This will be covered under the Approved Used warranty.

 

[TW666]

Presumably you've seen the list of conditions in the handbook (this is for my 2019 non-AMG car):

View attachment 153969




I would drive the car normally for a few days and if stop/start never becomes active (bearing in mind the above criteria) then simply ask them to fix it. This will be covered under the Approved Used warranty.

Thanks that’s a very long list, I’ll give it a few decent runs to check that Stop Start is never activated before contacting the dealer.

 

[Will]

OP - has it ever worked since you had it?

 

[TW666]

OP - has it ever worked since you had it?

No it’s never worked. I’ve only had the car about 6 weeks and done 200 miles due to family circumstances. I recently paid for a new starter battery as the dealer explained that it was not covered by the used car warranty.

 

[NJSS]

I have to say that I don't like Stop/Start sp would view this as an advantage!

 

[Will]

No it’s never worked. I’ve only had the car about 6 weeks and done 200 miles due to family circumstances. I recently paid for a new starter battery as the dealer explained that it was not covered by the used car warranty.

IMHO you shouldn’t have had to replace the battery, just let the dealer fix whatever the issue is.

Even if the battery was at fault, within the first 6 weeks I’d have expected the dealer to cover that.

If there is a fault with the system, I’d be making it clear to the dealer that you expect them to fix it at their cost - the warranty should not come into it if this was faulty when you got it.

 

[Smiley]

Maybe a previous owner found a way to permanently disable the (stupid) stop start system. I would treat it as a bonus. And I'd get my money back for the battery from the dealer; 1. because they misdiagnosed the problem and 2. it was their responsibility to fix it anyway if it was a fault on delivery.

 

[herby thr cls]

No it’s never worked. I’ve only had the car about 6 weeks and done 200 miles due to family circumstances. I recently paid for a new starter battery as the dealer explained that it was not covered by the used car warranty.

If you have Mercedes Used and Approved warranty the starter battery is covered by it, my starter battery was always showing only partially charged on the mercedes app and the Stop/Start never worked since i bought it.

I phoned Mercedes of Bishops Stortford and asked if they knew if it was covered? their answer was they didn't think it was but they would find out for me, a day later they called and told me only the starter battery is covered, but the Aux battery isn't, Happy Days.

If I was you I would call them and ask for a refund,

 

[W1ghty]

Can you call Mobilio breakdown out to check the car using their diagnostic kit ?

 

[Will]

Can you call Mobilio breakdown out to check the car using their diagnostic kit ?

I think the trouble is it won’t stop, not a problem starting

 

[TW666]

I’ve got the car booked in for mid April at my local dealer to have a warranty check on the stop start system, will keep you updated.

 

[mioba]

I have replaced two SS capacitors in my w205. They fail. It has died again and I am leaving it. SS does nothing good for the car but wears out components at an alarming rate. .