Would catless 3in downpipes have an effect on primary o2 sensors?

[616_S4]

My shop seems to think that having no cats in my system makes my primary o2 sensors read wrong. I bought new ones but they dont want to put them in because they think it wont make a difference and I will still get the same codes. Any help is greatly appreciated!

[getslideways]

What are the codes? They WILL make the secondarys toss codes (obviously), but will not make the primaries read anything thats not actually happening.

However, it is not uncommon for the primaries to go bad during a downpipe swap as they get knocked around, and are likely old to begin with.

[vavJETTAw36]

What are the codes???? I say if the codes are related to the primaries, go ahead and add them. They are easy to replace.


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[616_S4]

P1113 H02S 1 bank 1 heater resistance too high and P1131 H02S 1 bank 2 heater resistance too high are two codes I get, the shop seems to think that having no back pressure makes them go

Shop thinks I should put cats back in lol ya right!

[NOTORIOUS VR]

The primaries couldn't care less. You can tell your "shop" not to worry about it.

[S4tech2]

I agree I just replaced my primary O2 sensors today, I have 3 inch down pipes without cats and assuming that the sensors were from when the car was new in 2001 and getting faults for slow/no response is cause enough for replacement. Most shops don't have an understanding of how upgrades relate to the system and are "afraid" of them.

[kewe24]

I had the same fault after I put in aftermarket downpipes. I replaced the sensors and codes never came back. Plus they are super easy to do so you can save some money and do them yourself!

[airjawed]

Do not spray any contact cleaner or liquid wrench on the o2 wiring... it will make them go bad. Even the connector end all the way at the firewall. The liquid can travel down the wire and mess it up. Also the o2 uses the air coming in the wire as part of the sensoring system. Anyway, don't spray O2 sensor wires at all.