Thread: Rear O2 sensor (OBDII)

I've got a CEL for my rear O2, and I've got emissions coming up (scanner only no sniffer). I can clear the code, but it always comes back.

I did a little searching, and I found the thread on removing the O2; but I didn't see any updates on if that works after initially clearing the code.

Cheap is my preference, and it looks like $20 to do the mod in the thread, $40 for a "simulator", or $100+ for a new O2. If this modification to the existing sensor actually works I think I might give it a shot, but I wanted to see how long it lasts (we have emissions checks every 2 years).

Thanks,

Josh

I can tell you from personal experience. The rear o2 sensor does nothing as long as the front O2 is working properly. That mod works because the CEL gets thrown if the ECU does not get a signal. I have had mine out and off the car for 5 years, no issues.

As long as you make it watertight if you are leaving it out of cabin or keep it in cabin it will last forever.

So did follow the method in the How To? It seems like the 2nd method would be better, but I didn't know if any long term results were in.

Thanks for the feedback.

I believe Vadim has been using the mod for a long while now, see what he has to say.

It works well, especially after I got rid of the resisters for the heater and plugged in the O2 sensor instead. The problem that I'm having is finding a safe place to locate the O2 sensor, it does heat up and will burn your carpet. I was going to just weld another bung onto the exhaust and screw it in, but lost motivation .

But I highly suggest you have it plugged up for "visual" inspections too.

I was leaning towards your method that just puts the electronics in the loom, and leave the O2 in the exhaust.

So it looks like this:

well, you can get a new one for $40. Just sayin..

But yeah, it is useless for the car's performance, it only exists to nag you when your catalytic converter is not doing it's job.

With that resister fix the only time I will EVER have to get a new one is when the wire rip off

I'm curious about one for $40. According to RockAuto, most of the rears are $70-80. Fronts are $40, and I would have replaced it already since that actually functions.

Fronts are usually more expensive if you get the ones with a plug. Universal ones are cheap and work like a charm.

Use the Bosch Vehicle Part Finder to find which Universal Part# to use.