Does your car smell of gasoline after you fill it up? The 211 is equipped with a fuel tank pressure sensor. If your tank does not pressurize the code will trigger. The fuel tank on these cars is known to leak and the fuel tank warranty was extended to 15 years and unlimited miles. You might be experiencing this issue.

 

Car has no smell of any sort! I pulled out the back seat. Which side is the fuel tank pressure sensor located? I believe driver side is the fuel pump and passenger side is fuel filter

 

Void of fuel odor, fuel cap fine check following emission related parts. Although each will throw its own code if malfunctioning, P0452 relates to fuel tank pressure of which suggested parts contribute.

Check filler neck
Purge valve (part # 0004705593)
Charcoal canister valve (0004707193 + harness 211440034)
Charcoal canister (2114700159)

 

Thank you konigstiger. BTW where is the the fuel tank pressure sensor located on W211? is it by the wheel housing on the passenger side? I checked the purge valve and the filler neck. I don't see anything obviously wrong with them.

 

Part 1635422818 located @ driver side fuel filter.

 

I looked at both sides under the rear seat. I did not find a connector similar to this one. There is a 5 pin connector on the rear drivers side but the fuel tank sensor has 3 pin connector according to pictures I have seen. I am not sure where its located now

 

Try this...

 

The sensor in the video does not match the sensor at AutoZone, dealer or online. Do you think it's by the cannisters in the wheel well??

 

The pressure sensor and whole fuel sender/filter housing was redesigned after the whole fuel leak fiasco. You likely still have the old sensor.
https://imgur.com/a/6CaNUZv

In the first and second pic you can see the old design sensor. In the last pic is the PN for an adapter harness that makes the car's old wiring harness connect to the redesigned sensor. The pre redesign sensor is NOT serviceable on its own. You have to replace the whole filter/sensor/sender housing (driver's side). This has hoses and wires that snake through the tank to the passenger side where the pump resides.

This device is notorious for leaks. Fill it up to the top, park it over night with the full tank of gas. Pop the cover and check for leaks in the morning. If there's any leak or smell of gas at all the whole fuel tank including all the internal components gets replaced by Mercedes under the 15 year warranty free of charge.

The fuel tank in the video is a W204 not a W211. It does not apply to our cars.

 

I called Mercedes, my car was only covered till July 2018! I also called the dealership and have them look at the vin number for any recalls, they said my car has no recalls for fuel system. It might be a late 2003 model.
Btw I did see some fluid on top of the filter assembly but it had no odor to it, I don't know if it is gasoline or something else?

 

The campaign to extend the free replacement was for 5 years from the "in service" date of the car. It is very possible that
the car has been in service more than 15 years.