Hi all,

I posted here a while ago regarding the fuel economy of my W212 E250 (that post can be found here: https://mbworld.org/forums/e-class-w...w212-e250.html)

I have been so busy with life and haven't got a chance to take it to the mechanics for a complete check. I'm going to do that but I want to make sure I have at least a basic idea of what is going on. I bought an OBD II scanning tool, plugged it in, and get some data. Would appreciate it if you can offer some insights.

Live data (After drive for 30min, idling when taking the data. Can provide more information if needed):
DTC_CNT: 1
LOAD_PCT(%): 15.7
ECT(。C): 83
MAP (KPA): 83
RPM: 816
O2SLOC: B1S1---B2S---- (For this one, it is kind of odd as it doesn't show the B1S2)
EQ_RATB1S1: 1.999 (sometimes it fluctuates between 1.000 to 1.999, sometimes it doesn't fluctuates at all)
O2B1S1(V): some times it fluctuates between 0 and 1.5, and some times it fluctuates between 0.1 and 0.97. Very odd.
CATEMP11: 338.7
CATEMP12: 607.1
FUEL_RATE(L/H): 0.65
EGT11(C): 357.2
EGT12(C): 1200.00
DPF1_DP(C): 0.00
DPF1_INT(C): 600.7
CPF1_OUTT(C): 1200.0
NOX11(PPM): 65535
NOX12(PPM): 0

Other information: The car gives a P0471 error code which is related to the exhaust pressure sensor, and the check engine light is on. However, the check engine light will disappear after a few drives, then comes back up after another few drives, then disappear ... and so on. When it is on, the car has some weird behavior (e.g., shift at a different RPM, only goes to 6th gear, only goes to 60mph, etc. It will return to normal after restarting the car.).

Question: I somehow didn't see anything related to O2 sensor B1S2. I suspect some of these are related to the poor fuel economy I'm getting (~21/22 mpg on average). Previous owner of the car has done AdBlue delete and coded out the emission component (as identified by Mercedes dealer a while back).

Any help will be greatly appreciated!