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MAF [B2/5] is applicable to M276 with code U1020 [Valid for gasoline engine with stratified operation] and it would be a 5 wire connector. IAT [B17] is applicable to M276 with code U1021 [Not valid for gasoline engine with stratified operation].
Mercedes has quite the few variants/codes that can get you in trouble when looking things up. Since you mention 2 wires, then what your seeing is an IAT. The braided cable loop I just assumed is a built-in lifting "ring"... older models had stamped metal plates with round holes.
Figure below is likely M276 variant with code U1020:
Last edited by bmwpowere36m3; Feb 23, 2021 at 01:28 PM.
Reason: added variant code
Attached is the GDI system control unit wiring diagram, which distinguishes the stratified vs. non-stratified operation (U1020 vs. U1021 code, IAT vs. MAF).
Unless someone can definitively say... the documentation indicates only stratified M276 engines have a MAF. If you google M276 DES, DEH and stratified, there are few sources indicating the US market got non-stratified M276 variants and ROW (rest of world) got stratified M276. Seems all related to emissions, EGR and NOx levels...
WIS has A LOT of info and there's a learning curve. When using it, always best to enter the VIN of the car your working on and exercise care when reviewing documents/procedures whether its model year (month/year) cut-offs, option codes and/or variants.
2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
Originally Posted by Senecan
So we've been looking at DES info from WIS, which gave us B2/5. I need to get in front of my laptop. Thanks for the link, that was a good read. I'd really like to know how they are achieving a 14.7:1 AFR with no MAF. Not sure that calculation can be accomplished with precat O2's alone. Germans are smart, man.
RPM, displacement, manifold pressure, intake air temperature, and precise throttle position and you can calculate the air mass, accurately.
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