1990silverbullet
New member
so I replaced my O2 sensor yesterday but it is still giving me code 21. The Previous owner took out the cat. My question is, with the cat being gone does that effect anything or not? Could that be my culprit?
O2 Sensor replacment
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grousehunter 61
New member
Not sure but that would imply the o-2 works with back pressure, I don't think so, what ever goes past it is what it regusters. I THINK???
1990silverbullet
New member
So should I put a cat in just for safe measures? What are the benefits of having a cat?
128keaton
New member
1990silverbullet
New member
Still wondering if bolting a cat back in will solve anything. ill just have to buy one and find out. Thanks for the help ill let you know what I find out
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O.B.A.K
New member
I have a cat delete from lc engineering. It hasn't affected my new o2 sensor, I had the code, replaced the o2 and it went away.
My guess is the o2 sensor wiring is compromised somewhere. Did you use an oem o2 sensor? I have heard of sensors not functioning properly if they are non-oem. I went with a Denso unit.
My guess is the o2 sensor wiring is compromised somewhere. Did you use an oem o2 sensor? I have heard of sensors not functioning properly if they are non-oem. I went with a Denso unit.
grousehunter 61
New member
I am fairly sure that the wiring from the 02 has a fixed ohm reading any thing that changes that reading, cutting the wire, splicing the wire, will change the reading. Try to find a complete new wire and replace the old with it.
4RunnerAquasport
Senior Member
Not much experience with o2s, but have heard of bootleg sensors and other parts going around on the market, so be careful where you buy.
Really no way to hold online sellers accountable. A true Denso part is most likely closest, or OEM originally as you pointed out, but the evil ones have been doing good copies of those right down to the logos on the box.
