Richard Baker

Hi 👋 I drive a C220 w205, The other day I was going up a big hill and flicked into sport+ got to about 70mph and suddenly the EML light comes on and the car looses alot power, also whilst the EML is on the car is shifting horribly, not changing until very high rpm and also shifting down to 1st too early when I'm slowing causing a jolt, also whilst the EML is on I cannot use the paddle shift, guessing it's some sort of safety mode. So I had the code erased (p0101 MAF sensor) and went for long drive to see if it came back, drove for about 20 miles perfectly then when I was joining onto the motorway on the way home, exactly the same scenario. I flicked into sport+ to join from the slip road got up to 70ish and boom loss of power and EML back with horrible shifting. Ordered a new genuine continental MAF and fitted it today, had the codes erased and took it for a drive, it drove perfectly until i thought I would try out the sport+ again and put my foot down, bang same boat 😭 EML on again! Any advice greatly received. Thanks.

PaulR7

Did you have the car tuned or does it have a piggyback chip on it?

Richard Baker

No not been tuned and no piggyback chip

PaulR7

Then you might have a vacuum leak considering the sensor was replaced. I'd suggest connecting the car up to Xentry and running all of the related tests, you might need to take the car to the stealership or a specialist.

Richard Baker

Ok 😢 what was the thought process with there being a tuning chip? Because there is something fitted to the car... Not for tuning and it's been there a couple of years with no issue but it is a electrical chip of sorts

PaulR7

An ECU tune should normally actually change the values in the brain of the car so that should not throw an error but it's still possible that the tune itself is faulty which could potentially make the car think it's getting too little/too much airflow and throw up an EML.
With a piggyback chip most of them read the boost data and feed a lower value back to the ECU so MAF compensates for it and changes the fuel trim.
If whatever electrical chip you've got connected down there messes with anything related to the turbo, engine or even thermostat I'd just remove it and run the car for a week without it to see if that fixes your issue. If not go back to what I said about Xentry.

Richard Baker

Yea good shout, I will definitely disconnect it and test without it. Thanks for your help