KevMBC300

Hello everyone, I have a 2015 C300 4 Matic.. A few days ago the check engine light came on throwing the code p052e71, My mechanic told me it was the crankcase ventilation valve that needed to be replaced and that I should also change the thermostat as well. I had him change both those parts, I got the car back but I noticed the acceleration is extremely slow. Before the parts were changed the car would get up and go fast there was no delay or anything. Now when i hit the gas the RPMS are going up to 5000 before I feel any substantial movement and the car feels sluggish, Comfort, Sport and Sports Plus all feel the same. Its doesn't feel like turbo lag cause there is no sudden burst of speed. I contacted the mechanic but he's saying if there is no check engine light he can't do anything and i should see if the light comes on first before I bring it to him. If anyone has any advice please let me know. Thanks.

chassis

Open the cam magnet and cam position sensor wire connectors and check for signs of oil. With a nearly 10 year old car, replacing the O2 sensors is never a bad idea.

CaliBenzDriver

Kev, you went to the wrong shop. Nearly anyone can hang cheap parts... troubleshooting is what you need.

CEL are extreme fault conditions... your case is only halfway there without active light.


Someone you or technician needs to read the chassis computers to help come up with a matching course of actions.

The list of suspects for reduced power is pretty wide... wastegate filled with oil or some intake parts that were disturbed during PCV replacement.

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KevMBC300

Took the car a Mercedes Benz service center, They changed the knock sensor, spark plugs and serviced the transmission. Car runs perfect now and lesson learned.