O2 sensor secondary

[Drift King]

yeah this is a 4 wire denso. The colors on it are, black, black, white, and blue. I havent taken the old one off yet.

[Smoghog]

Originally Posted by Drift King

OK. Got it superblue. Last problem, do you remember what wires were which on the OEM plug? This one came with a chart saying this color goes to that color ect, but I cant see how it can be the same for all cars. I guess I need to know the ground, heater power 1 & 2?, and signal wires.

You have two grounds, one power and one signal
Two black
one yellow or red=heater+
one white=signal

Get out the voltmeter Yellow should be 12v. with key on. White should be 0v

SH

[superbluecivicsi]

the two blacks are ground and its polarity does not matter with the old harness. there should be a power and signal. match those two with the old harness. the denso instructions should identify those.

[Drift King]

Ok sounds easy enough. Just looked around the sensor before and it didn't look like you can get the whole thing out including the pigtail connector because it goes up through a small whole in the underbody. Did you just use the small amount of wire under the car to connect the new O2? It would be easier to get the whole thing out, if you did it that way, how? thanks.

[Drift King]

guess not..

[superbluecivicsi]

you can just make start splicing wires right under the car, or, you can yank on the harness until the junction plug comes out.

[Drift King]

Oh man... back. I finally got around to doing this, eveything went fine until I had to crimp the wires together at the end. When I was stripping the coating off the wires hanging out of the underbody one of the wires fell out. So that must mean it pulled right out of the pin connector, great. I was thinking that might happen so I was trying to hold the wire steady the whole time but it just came out. So is it hopeless now? even if I found wherever the pin connector is, how could I put a wire back into it..

[superbluecivicsi]

just go back up the wire and solder them back on color matching the original wires. if not, you can always rewire from the ecu back down.

[Drift King]

ok, but I dont know where the wires go up into the car. It looks like its just behind the firewall or something, how do I get to the location. Or are you saying the wires go straight to the ecu, because the wire that came out was only about 5in. long.

[Drift King]

Yeah, I still cant find the hole the wires come through inside the car. I tore up the whole area around the upper console but I don't see any hole in the floor, is it even able to be reached?

[Drift King]

OK, I found the hole, rewired everythings in place. I thought there would be a short because I was driving for a while without the wires connected. So a code did come up, 65 short in circuit of secondary O2 sensor. My owners manual doesnt have a location for the fuse. Can somebody tell me which one it is? That is what the short is linked to right? By the way the wires on the old one were blue white black black, the new one was green white black black. I connected the whites, blacks and then the blue to the green, hope theres no problem with that.

[superbluecivicsi]

rewire it up and reset the ecu. also, check your other post.

[Drift King]

Alright, looks like I have to go back under there. But first, how do you reset the ecu, I never did that.

[superbluecivicsi]

pull the negative cable off the battery for 10 secs then put it back on. cel is reseted.

[Drift King]

Well, I reset and the light came back on so the code wasnt stuck in there. I bought a voltmeter and tested the volts on the ecu side of the O2 connector. The wires on that side are; white with a red stripe, green with a white stripe, black with brown dots and black with silver dots. Oddly, the only reading with the key on came out of the black with brown dots. Even stranger, the other side on the O2 connector that connects to that wire is one of the black wires. So thats definitely something wrong then right. We thought those black wires were grounds but one isn't and on the O2 side they are both flat black, cant distinguish between them. So on the O2 side green goes to green, white goes to white, one black to the black with silver and the other black to the black with brown. Now how do I distinguish between those colors connecting to the new O2 sensor. I have the old O2 and can match up the wires as to how they go around the connection to the O2 but its impossible to tell between the two blacks. Also, when I tried to read the ohms I didnt get anything, and I saw it says it cant read under 100 ohms in the instruction book. What am I going to do!?