Ml400 epc light
The code it logs is p2020 rail pressure afterunning test quantity control valve.
Can anyone advise if they have seen this before or have any advice, I don't want to change the qcv if it's not likely to be that and could just be fuel filter or something, i have twice seen 1 air bubble in the clear pipe from filter to pump, i wondered if the pressure would be dropping off too quickly after shutdown? To add, the epc light never comes on whilst driving, the code is logged when I turn the engine off.
I look forward to any replies, thanks all


