Oxygen Sensor Woes

[jplong]

Ok im at wits end here trying to trace out why i'm still getting CELs for my 2 downstream Oxygen sensors. Should i have a spacer on Both of the rears? I have a 2009 TSI with 3 Oxygen sensors. 1 (what seems to be a wideband) up at the turbo outlet. 2nd just before the highflow cat in the CTS DP. and the 3rd just after the Cat in the DP. I am consistently getting errors on sensor 2. Does sensor 2 modify fuel curves? or is it only in place to monitor Cat effiencey of the "pre-cat" that was in the stock turbo downpipe? My car seems to run very rich as well.

 

[snobrdrdan]

Get a Stage 2 tune, to go with that downpipe, and that'll solve ALL of your problems
More power and no spacers needed

 

[jplong]

Stage 2? i guess i should list out my other mods. but no a stage 2 will not fix my problem. K04 with a full 3" exhaust, AFE intake, R8 Coils, Divert Relocation. Im on a K04 Tune already oh....and GO Bucks!

 

[BurgerGuy]

What codes are you getting?

 

[jplong]

P0140 O2 sensor circuit no activity detected
P0141 O2 sensor heater circuit

Have tried 2! known good O2 sensors. so thinking the wiring is messed up somehow. but i have tested the car side of the connector and the wiring seems good. ground is ground and there is voltage on the heater circuit. wondering if the wiring is in corect pins...?

 

[jplong]

finally took to a shop and after 3 days they said i had a Bad ECU. I find this hard to believe. as they also said that there was no continuity between the ECU and the O2 Sensor. does anyone have a pinout for an 09 ECU?

 

[GTI's]

So to confirm this is a CBFA engine code.

 

[jplong]

yes

 

[GTI's]

Check PM and yes a O2 heater issues can cause damage to ECU that why you need to fix asap.