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      11-05-2012, 11:23 AM   #2
No 55mph
1QuikWS6's Avatar

Drives: 09 E92 328iX N51 3-Stage ->M6
Join Date: Jul 2009
Location: Blitzburgh, PA

iTrader: (89)

Garage List
Items #1 & 2 are the pre-cat sensors that help to control car in Closed-Loop mode - hence the word 'regulating' in the description. They read the O2 level in exhaust right after combustion & send this info to PCM. If there is a problem with how the car runs, & it's related to the O2 sensors, then these are the suspect ones.

The other (2), items 4 & 5 are for monitoring effectiveness of cats - if the cats are going bad, these will tell the car based on after-cat O2 levels.
2009 328ix E92//SGM//ACS Roof Spoiler//MTech Aero Lip+Trunk Spoiler//M3 Side Skirts//CF Roundels+Grilles//M3 Novillo Interior//Perf Shift Lever+Boot//MPerf DCT Wheel//M3 GT3 eBrake Handle+Boot//ACS Pedals//M3 Mirrors//LCI Tails w/LUX Rev//LUX 160 AE+MTec 6000K D1S+HPB HID 6000K Fogs//HPB LED Interior//RPI Scoops//CF Euro Airbox+Underhood Hsgs//K&N//BMW PE//MTech Rear Bumper-iS Sport Diffuser//CF Strut Brace//AA Stage3//BMW 193M's+Kumho 4X