Oxygen Sensor Bypass/ Simulator

421 Views 6 Replies 4 Participants Last post by Incognito, 13 d ago

Incognito

So recently went back to catless after passing emissions and didn't want that little engine symbol popping up again with the typical P0036 and P0139 codes. After scouring the interwebs I located a hack where you place a resistor and a capacitor in the O2 sensor wires. This got rid of the P0036 and P0139 codes even without a O2 extension but now I have a P2270 code (O2 sensor stuck lean), so FML. I'm wondering if a lower ohm resistor would get rid of the code. Just thought I'd share and maybe see if someone else has done this.

Parts:
One 1 MEG ohm 1/2 watt 1% metal film resistor
One Capacitor 1 uf/microfarad 50 v/volt 85C Kemet Radial

... and here's my hack job. Everything was shrink wrapped afterwards and heat shielded.

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RPW00Mirage

· #2 · 15 d ago

this worked great for my 2000 mitsubishi mirage going catless... not so sure about todays modern veloster turbo.

why wouldnt you use the tried and true o2 spacer?

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Incognito

Discussion Starter · #3 · 15 d ago

RPW00Mirage said:
why wouldnt you use the tried and true o2 spacer?

I have, several iterations of them too, but the CEL ultimately comes back. Oh well, 1st world problems I guess 😄 Maybe i’ll do the electric tape mod, lol.

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trdtoy

· #4 · 14 d ago

A proper spacer or elbow or tune will get rid of the catless CEL P0420 and not cause other codes. Tune to do so is the sure bet.

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Bland

· #5 · 14 d ago

But tuning it out leaves the sensor in a not ready state. That would usually cause a fail for emissions testing. On one of my previous cars I managed to get a secondary 02 in a ready state with a spacer, but it was temporary. The cell would come up every now and then, but I made sure to schedule my appointment when it was green

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trdtoy

· #6 · 13 d ago

Bland said:
But tuning it out leaves the sensor in a not ready state. That would usually cause a fail for emissions testing. On one of my previous cars I managed to get a secondary 02 in a ready state with a spacer, but it was temporary. The cell would come up every now and then, but I made sure to schedule my appointment when it was green

This can be true in some cases regarding tuning it but not always.

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Incognito

Discussion Starter · #7 · 13 d ago

trdtoy said:
A proper spacer or elbow or tune will get rid of the catless CEL P0420 and not cause other codes. Tune to do so is the sure bet.

Maybe I'll try it again. I ended up having to replace the O2 sensor for it was faulty so maybe the new one will cooperate. I've never had a P0420 code. Its always been the heater circuit codes.

Bland said:
But tuning it out leaves the sensor in a not ready state. That would usually cause a fail for emissions testing. On one of my previous cars I managed to get a secondary 02 in a ready state with a spacer, but it was temporary. The cell would come up every now and then, but I made sure to schedule my appointment when it was green

I just swap between the catless pipe and the catted pipe for emissions testing. Incidentally I had one occasion where there was no CEL codes but the ECU was in a "not ready for emissions" state. Ended up having to drive it for a couple of days until the ECU performed several tests and became "ready".

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