I posted a week or so ago regarding my poor gas mileage, etc. due to my original o2 sensor wiring splitting and blowing my EFI fuse. Well being the cheap person i am decided to buy a new 02 sensor for $15 off of Ebay. Went to install it last night and its a 4 wire connection just like the OEM with 2 black, 1 blue and 1 white wire. Spliced into these and was wondering if it matters which black goes to which black on the other end? My CES light is still on so im not sure if it makes any diff. or if its due to the actual sensor itself being cheap. I did try to reset the ECU and drove it 60 miles to work this morning to see if it would make any diff. but no luck. Tonight ill rewire the old sensor and see if it goes away but thought id ask you guys since its really bugging me. ( i did search but the only thing i could find was that universal sensors usually dont help) i can get my $ back for it though

 

i know the 4 wires are one signal, one ground, and two
heater but dont know which is which. i have a service manual but doesnt tell me.

 

what brand of sensor is it

 

its supposed to be a Denso sensor. so does anybody know about the black wires? none of them have any stripes or anything, just 2 black out of one harness and two black out of the sensor.

 

i have a universal on mine i will go look at the wires and tell you where they go

 

id greatly appreciate it

 

i forgot to ask but what color wires are on the universal one

 

2 black , one blue , one white and when splicing into the existing harness its the same colors but dont know if it makes a diff. which black goes to which black

 

Did you clear the CEL code by pulling the EFI fuse or disconnecting the negative battery terminal for 10 minutes?

Maybe i missed it.

MIke in AR

 

i dont think it really matters where the black wires go i think there both a ground

 

Does make a difference! one is ground for heater and one for signal! I put a universal on my wife's Honda and the CEL would come on, if I let it warm up for about 30 secs then cut it off and restarted it no more CEL(Heater part never worked correctly). I finally bouth OEM and no more CEL at all!

 

well i took out the new one and put the stock one back in and the CEL light is STILL on. ive pulled the fuse and had the negative battery cable off last night with no luck. i drove to work this morning (60 miles )but CEL is still on. seems to be a little lower on power for some reason and cant tell about gas mileage yet. i guess ill return the newest one and buy an OEM type with the harness from autozone for $90. any other suggestions? what is this ive heard about Toyota replacing sensor for free at 80K miles? if the original owner never took advantage of that am i eligible or is it BS?

 

So, for reference, this is your original post from the other thread:

To recap, the original problem was that you found a loose wire that was (seemingly) grounding out and blowing the EFI fuse. Was that wire one of the wires to the O2 sensor? If so, then what "O2 wire" did you cut in half? If you had two wires hanging, then why not just tape them up without cutting anything?

After you did this, you threw a code, which you/we suspected was because of you basically the O2 sensor out of the circuit. But now.. you've replaced the O2 sensor with a universal, reset the ECU, and there's still a code? Have you pulled the code?

When you reset the ECU (by pulling the battery cable) then does the CEL come on as soon as you start the truck?

It may all seem academic, but I think it could be worthwhile to pull the diag code to be sure that you're fighting the problem you think you are.

 

it was actually 3 out of the 4 wires had rubbed themselves pretty much raw and were literally frayed and shredded. they must have come in contact with one another causing the EFI fuse to blow and causing the truck to cut off. Instead of repairing it then, i just cut all 4 wires and taped them up. I figured it would be a good idea to replace the 02 sensor since the truck has 150K+ miles on it and after rewiring im still getting a code but i wasnt getting one before the wires shorted out. i havent even checked for codes yet ( i know i should have) but i just figured it had to be the wiring since it wasnt doing it before. sorry to be such a newb

** Ill go outside and pull the codes on my lunch break and see what comes up

 

ok just checked and it blinked 4 times, 2 times, 2 times, 1 time

i went here:
http://www.off-road.com/toyota/tech/codes/index.html

few seconds in between 42 and 21. went to autozone and they couldnt find the port to check the codes

 

Hmm,, the 42 is a speed sensor code, according to the chart. If the speed sensor is out of the loop (for whatever reason), it may be confusing the ECM. You'll probably have to check the speed sensor for accurate operation.

Check here for more info:

http://personal.utulsa.edu/~nathan-b...34electron.pdf

Mike in AR

 

yeah my speedo hasnt worked since i bought the truck and that same page shows a 21 is o2 sensor. so does anybody know a way to figure out the deal with the black wires?

 

Okay, so at least we know that the ECU really is complaining about what we hoped it was. Thanks for doing that - I can sleep at night now.

I just found these:
http://dodgeram.org/tech/gas/Trouble/O2_sensor.htm
http://www.ecanfix.com/~mdhamilton/o2sensor.html

I think that between the two of them you may be in a better spot.