Is it possible that you accidentally activate the ‘limiter’ function?

 

Unfortunately not. I think it maybe a faulty throttle body or the module that operates it. When you turn the engine off and on it reboots the system like your PC at home.

 

One last thing to try when you experience this next. At the end of the throttle pedal travel, there is a "kickdown detent" - ie - the pedal travel will be smooth until near the end, then when you press further with your foot, it has a further 1/4 inch to travel, past a notch/detent.

Try pressing the pedal past the detent/notch to see if that brings it out of idle.

 

Thanks. I will try it.

 

I have a 2020 a200d automatic. It has been great so far, no issues until a few days ago. I was coming off a roundabout and pressed the accelerator and it didn't accelerate like normal, it accelerated really slow like it was stuck in a high gear and not downshifting. I drove for a few miles and it continued like this, with very little power. I pulled over, restarted the car and the issue was gone. My question; is this a common issue? There were no weird sounds/smells, nothing that would indicate any form of hardware issue. Could it just be a software bug? Is it worth contacting Mercedes? If it is a software bug I doubt they will do anything.

 

It depends on how much you like visiting your dealer. If there’s no obvious problem at present they are going to look at your car over several hours and be very sympathetic but nothing is likely to change. I’d advise waiting until this becomes a more regular and repeatable issue before contacting your dealer.

 

@stuartlz You accidentally activated the speed limiter?

Try going past the ‘detent’ position on the throttle pedal as described in post #4 above next time it happens.

 

I think this problem is now resolved. I took my car to an independent Mercedes workshop I have known for many years. We put the car on the diagnostic tester. We found that the alternator was overcharging. My dealer did not pick this up. If the charging system is is charging too high the ECU shuts down to protect its self. The car is back at Temple Fortune (London) awaiting a new alternator from Germany. Everyone is convinced this is the problem. I hope they are right.