Rear O2 sensor bypass/CEL fix.

I'm going to "lob the ball" here and post that it's going to take a bit of research on your part. Sorry, but I don't have those values and test procedures for your specific truck and sensors in front of me. A quick look around TW found some interesting reads. Some stuff on youtube about heating sensors and checking for top values and response time of the sensor, for a 4 wire, 3 wire, 2 wire, 1 wire.

I needed a pic of your exhaust in front of me,,so this was found pretty easy and I think it is close.
https://www.tacomaworld.com/threads/cat-converters-3-4-underbody-pictures-please.168614/

Just spitballing here, but I think you need that second cat or your muffler in place again for this to work. Your muffler is gone and the second cat is gutted. From what I have seen so far, it needs the factory back pressure of at least the muffler.

 

The only reason I joined the forum is because YOU GUYS GOT IT WRONG!!!. i don't know if you all are really dumb or just ignorant. but THAT IS NOT HOW YOU WIRE IT.
i hope for fucks sake not one of you is a real mechanic. cause this is 3rd year shit simple wiring. and it works on most brands of cars and trucks in north America with a 4 or 5 wire set up

this is the proper way to wire it. the other way is retarded and won't work at all, you just make a loop.. like plugging an extension cord into itself. i suggest you kids go back to school. yes i know this is an old post but i found it on google and got pissed off at the stupidity.. i should have guessed import owners are too dumb to figure out simple wiring

 

Like my original post,,from info put together years ago from someone else. It works. Works better for some,,not so much for others.

Thanks for the optional wiring path, might try it to see.

 

Well I put it in this morning and reset the light. I drove around 30 miles so far today and no light so it's looking good!

 

I'll be damned. Just proves the theory, that all trucks are not created on the same shift.

If that pops back on again, Reset it overnight. leave the batt leads off till its needed if you can.

 

I jinxed myself. Right as I pulled back into the driveway. Reset it and it came back on after about 30 miles the next day.( with my scanguage) I'm not giving up on this though I know I made it right I tripped checked it.

 

I'm wondering if you do need a working 02 sensor for this to work. I feel like that's what's throwing the code on mine then if I get a replacement sensor and it works, I'll get a p0140 then this will work for me. Think that's my next step now

 

So I read through this and still am not sure on the best way to wire it in. I'm running 3" exhaust off the turbo, no muffler no cat, and have just been running with no rear o2 sensor for the last year but it's inspection time again and I'd really like to not have to go back to n/a just to pass. I wired my plug back in and zip tied it up to the frame and after about 30 min of driving today, I'm throwing no codes yet *fingers crossed*

 

Inspection crap.

That reads as the sensor is out of the stream, ziptied to the frame, and wired back in with the resistors in place?. Glad the light is now off,,but how in the hell does that pass?. Payola?.

Do they roll under the rig and look at anything during those inspections in NC?.

Lucky to be living here. I really wonder how much longer that luck will remain in WA state.

 

No, i haven't done the resistors yet as I'm not sure which is the proper way to wire them. NC is very lax, unless you go to a big chain they don't look. Luckily I know a guy that can help me out with other things but a CEL isn't bypassable. I'm allowed 2 not ready's so I'm hoping e erything will work out and evap and catalyst can be my not ready's lol

 

I know a bit about wiring diagtams and noticed a couple of discrepancies in the diagrams at this link. First off, the two diagrams are not wired the same. The first diagram does not remove the O2 sensor from the circuit. The resistor is in series with the white wire and the cap is in parallel with the sensor on the white and blue wires. Both white and blue are still connected to the sensor. In the second diagram the resistor is in parallel with the cap and both are in parallel with the white and blue wires and the sensor is disconnected, eliminating it from the circuit. The link talks about eliminating the sensor, so I would assume the second diagram is correct. This is the way Mod has his wired.
The diagram Holyghost23 posted is the same as the first diagram on the link, which does not eliminate the sensor.

 

I went to RadioShack. The exact parts and put on my 99 and it did not work

 

Crap. Have this code. Not entirely sure what it is yet. Got abut 6 months to figure it out/sort it out.

 

more than one way to do it
heres an 02 sensor confuser some guy made (I wouldnt do it because I obey all federal laws no matter how idiotic, and I worship Mother Gaia )
thinwall brass tubing press fit into place, reduces rear 02 reading enough to not throw code and with a new 02 sensor in front it will supply adequate fuel trim to get you by until you get your student loan paid off or play enough gigs at honkey tonks to save up for a magic catalytic converter that will save the world from pollution

 

Cool. Thanks. Another one to add to the list. Had read across that little trick not to long ago. No cross holes drilled in the bottom,, just the tube pressed on with the one I seen. A different material I think.

Would take some serious banjo work to get enough duckets to find that Magicat.

 

The fix works.

Interrupt the blue wire (signal wire) with the resistor (resistors have no polarity).

Bridge between the blue wire (signal wire) and the white wire (earth/ground wire) with the capacitor (capacitors are polarized), the negative leg of the capacitor goes to white/earth/ground.

The diagram in post #83 is correct.

The following Youtube video explains the workaround, it also details how and why it works.
You'll notice that in the video the fixer uses a 4.7μF capacitor as opposed to a 1μF.

(μF = microfarad)

The microfarad rating influences the duration of the of the pulse (oscillating wave length) from the sensor.

Some ECU's measure pulse duration and set a code if the duration is to long or short, typically this software is not found in most Toyotas ECU's.

This fix is for REAR (Downstream) sensors only****



The Capacitor:
https://www.radioshack.com/products/...ant=5717323589

The Resistor:
https://www.radioshack.com/products/...ant=5717290629

 

Cool. Thanks for the info to this thread.

 

Some of you might encounter O2 sensors with different colored wires than the double black/blue/white set up spoken of above.

Here are a couple of links that detail the sensors with different colored wires.

http://www.academia.edu/5496281/O2_...from_http_www.hiflo.com.au_oxygen_sensors.cfm

http://home.earthlink.net/~jcgebhart/o2sens.html