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Rapid (CCS) Failure to Charge (now diagnosed as a DC Connection Unit Failure)

3221 Views 9 Replies 2 Participants Last post by  TommyC1991
Hi all,
First time poster.

I’m going to put the end to end experience on here to maybe help others in the future.

I took delivery of an new EQA 250 in October and have put ~5000 miles on the car since.

Up until today all has been well, with a combination of 11kwh (my main source of charging) and 50Kwh charging (about 8 times in total) being used. However, this morning (with a long trip ahead of me and only 25% charge) I went to the local rapid chargers in Glasgow - there are about 12 in one place - I couldn’t get the CCS charger to work.

I tried multiple 50Kwh CCS chargers with the car not ‘seeing’ any of them and not charging. When connecting to the AC 22kwh charger the car recognised it was connected and then began charging successfully - albeit it would take 6.5 hours.

I phoned Mercedes Me who couldn’t help; apparently because I can slow charge, they can’t offer me any resolution on the day. It’s Sunday and the local Mercedes repair centre is closed.

I’ll update tomorrow once I’ve phoned Mercedes again with how I get on. My expectation is they will take the car in to run diagnostics.

I’m very unimpressed and in all honesty it has made me begin to regret buying an electric car.



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Did you try the Mercedes’ assistance tel no via the car or is that whom you mean by Mercedes’ me? Did you try an alternative charging station ie belonging to a diff company? I have only home charged and used a local lidl which has not been easy down to the lidl chargers not working most of the time and even now only 1 of the 2 works. Keep saying I need to get some experience of using public chargers as an experience like yours soon makes life stressful. Keep us posted.
Hi Parkwood,

You are correct - I used the built in tel no via the car; but as previously stated Mercedes were unable to help. They said it’s a “grey area” as the car is still able to charge.

I tried 5 different charges (all the same brand) in the same location- one which has a Tesla charging who kindly stopped to let me try to see if it was indeed the car which was at fault.

I didn’t try another brand. The AC charger on the same brand chargers did work.


Phoned the local Mercedes Garage today; I was correct that it needs to go for diagnostics. The first available appointment for diagnostics is the 15th of April (which is dreadful). They advised I phone Mercedes breakdown - the same number I originally phoned who couldn’t help.

I called the Mercedes breakdown team who did offer to help this time, but they can only send a live breakdown engineer - the car is currently with my wife in a secure carpark which they won’t get access to. I’m to phone back tonight once the car is sitting on my drive and they will send someone out.

I’m not very hopeful tbh. Update 3 will following tonight.
one assumes he might be able to run a diagnostic of the charging system via the obd🤔just the sort of thing to give BEV a bad name. I am concerne that the mercedes me service did not seem particuarly helpful or capable.

The mobile merc tech couldn’t get to me until this morning. He arrived at 7.45am.
He ran diagnostics which showed an error with high voltage charging - and he completed a software update.
I was advised to take the car to a rapid charger and see if this fixed the problem - it didn’t!
I was then told to take the car to the Mercedes garage (the same one which gave me a date of April 15th).
They now have my car but won’t be able to look at it for 48 hours.
I got a lease car (which is also an EQA - however this took 3 hours and much complaining to sort
thanks for update so we at least know there is an error on board await the next uodate with interest. It is no consolation but ICE cars have problems too just as frustrating. 🤞it gets sorted quickly.

Mercedes have been in contact. The car requires a new “Direct Current Charge Connection C/Unit” which is covered under warranty.

I’ve asked for more info; however my understanding is that the DC connection unit on the car (I.e where the cable gets plugged in) has failed after 4.5months/ ~10 usages.

The ETA on the part needed is currently “unknown”. My next update will be hopefully what caused the failure and when they expect the part to arrive and be installed.


Glad you have a diagnosis, I assume there is some sort of chip control unit in these units that governs the conversation between the car and charger and as such could be at risk from charger malfunction as well as it’s own manufacturing failures🤷‍♀️ I do doubt they will identify the cause but it is the first I have heard of. Now the only problem is part availability no mean mountain to climb good luck🤞

Got my car back yesterday after 2.5 weeks of being with Mercedes. Rapid charging is once again working - let’s hope it was a one off.

For future reference if you plug in the charger and the dashboard doesn’t move to the charging animation and the socket doesn’t light up/flash orange - it’s not seeing the charger - Mercedes didn’t really explain to me what caused the fault, just that the DC charging unit needed replaced.


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