Hello everyone,

My 2011 ML350 Bluetec has been displaying a check engine light intermittently for the past month. The code has appeared once after topping off the adblue tank and a second time after the vehicle had an A-Service done at Mercedes (adblue completely filled by service dept). The code that I have read is 20E821 FAULT: The pressure in the AdBlueregistered system is too low (I know it is not an MB code, but it is all I have!).

Is this code for the adblue pump or the heater? There is some information saying that it could be either according to my online research. Is the heater and the pump one unit?? Because I have already replaced the heater at the dealer and it has a warranty that is still valid.

Thanks

 

20E821 is not a valid code.

 

Just curious is the adblue pump and heater contained in one unit? Or are they separate? Thinking of maybe doing a DIY. The code I have (though not a valid MB code) only comes on in colder weather...

 

The heater element is contained in the pump.

Please UPDATE YOUR PROFILE in USER CP to include the year of your ML.