Which ones here are the pre-cat oxygen sensors?

autoque · 11-04-2012, 10:08 PM

The ones that are changed when something is amiss, which are they?

1QuikWS6 · 11-05-2012, 09:23 AM

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.

autoque · 11-05-2012, 05:38 PM

Thank you for the detailed explanation.

11-04-2012, 10:08 PM	#1
autoque Private 8 Rep 89 Posts Drives: '08 X5 3.0si Join Date: Mar 2010 Location: Outside NA iTrader: (0)	Which ones here are the pre-cat oxygen sensors? The ones that are changed when something is amiss, which are they? Attached Images
	Appreciate 0 Tweet Quote

11-05-2012, 09:23 AM	#2
1QuikWS6 No 55mph 1621 Rep 8,476 Posts Drives: F32 435ix MSport Join Date: Jul 2009 Location: Blitzburgh, PA iTrader: (113) Garage List 2022 BMW M440ix Vert [0.00] 2015 BMW 435ix MSport [0.00] 2000 Pontiac Trans Am [0.00]	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. __________________ F32 435ix//MGM//M Sport-Prem-Tech-Driver Assist-Lighting-Cold Weather-Dyn Handling Pkgs//M4 Black Lthr Int w/M4 Alum Blade Trim//HK w/Bavsound Stg3//763M//M4 Euro LCI Tails//M4 Mirrors w/CF Covers//AWCarbon CF F/R Spoilers-Side Splitters-Diffuser 6WB/ID6 HU+HUD/IND M4 Alcantara Armrest//PURE S2 Turbo//AA FMIC+DP//ER CP+TIC//3.5bar TMAP/TS DV//AWE Tuning Exh w/Blk Tips//Turner MS CF Intake//BM3 Cary Jordan Tune//MPerf Diff//PrecRW Ignition Kit
	Appreciate 0 Quote

11-05-2012, 05:38 PM	#3
autoque Private 8 Rep 89 Posts Drives: '08 X5 3.0si Join Date: Mar 2010 Location: Outside NA iTrader: (0)	Thank you for the detailed explanation.
	Appreciate 0 Quote