June 18 UPDATED Cliff Notes
Plugged in IAT and no more CEL 1 . Still getting CEL 41 heater code. Heater wire is wired directly to the A6 ECU pinout. I took my multimeter and check the resistance between the two white wires and here are my results. I admit I am not good with this crap so......

2000k.....000
200K.......00.0
20K.........0.00
2000........004
200..........04.3

does that mean anything to anyone

CLIFF NOTES FOR THREAD BELOW:
converted from 5wire to 4wire oxygen using OBD2A plugs/sensors. Matched wire functions and then splicedyellow/black wire into #4 injector yellow/black wire. Car throws CEL 1 (primary O2)


Info:
2000 Civic HX
OBD2A
P28 ECU

Okay I traced down what colors go to the 5wire and 4wire respectively.

Here is what I came up with:

5wire (OBD2A)
D11 grn/black wire - sensor ground
D7 white - 02 sensor output
A6 black/white - heater control ground

4wire secondary (OBD2A)
grn/black - sensor ground
white/red - 02 sensor output
black/white - heater control

Here is what I did...

Cut the 5wire engine harness side plug off, cut the 4wire engine harness side plug off. Then matched up the wire functions and spliced/taped (soldering was going to be done once I knew everything was running like there originally was a 4wire plugged in).

So:

green/black - green black
white - red/white
black white - black white

I then spliced the yellow/black wire to the #4 injector yellow/black wire.

car starts, idle is between 1.5 - 2K and I am throwing a code 1 which is primary oxygen sensor according to the ECU FAQ on this forum. My next question is I am using OBD2A plugs/sensors on a OBD1 ECU. That shouldnt make a difference correct.


Modified by specv5150 at 8:20 PM 6/18/2005


Modified by specv5150 at 8:20 PM 6/18/2005


Modified by specv5150 at 9:25 PM 6/18/2005

 

Anyone???? I have tried several different wiring setups and I still get the same code. I even tried using a brand new oxygen sensor to no avail....

 

From what i heard it is hard to convert 5 wire to 4 wire. but it seems that you are on the right track. I may be wrong but...

 

May I ask why you chose to do this conversion?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM-97CX &raquo;</TD></TR><TR><TD CLASS="quote">May I ask why you chose to do this conversion?</TD></TR></TABLE>

A) 5wire is WAAAAY more exspensive than 4wire

B) I am using a chipped P28 to go turbo and P28 requires 4wire oxygen sensor

 

Gotcha. I wish I could help you out man but I don't really do things like this too often at the dealership. I will ask around and see what I can find out though

 

WHITE WIRE(PHO2S (PRIMARY HEATED OXYGEN SENSOR,SENSOR 1) Detects Primary heated oxygen
sensor


Black/White PRIMARY OXYGEN SENSOR HEATER CONTROL) Drives primary heated oxygen sensor

Green/Black (SENSOR GROUND} Sensor ground.

Yellow/black - going to injecotr #4 yellow/black. I took these from the Helms.


Can anyone see if I am missing something? I re-checked all my wiring today and I am still throwing CEL 1

 

https://honda-tech.com/zerothread?id=1180819

run all the o2 wires into the ecu

 

i just ran all my wires directly to the ecu

 

I am goign to use some of the info supplied in the linked thread ans ee how it goes......I dont know what I am doing wrong.....I got the oxygen sensor to heat up........the car idles fine after letting it sit for a few minutes.

edit: I can just splaice right? I would splice the original ECU harness OR the conversion harness or does itr matter.....


Modified by specv5150 at 4:51 PM 6/13/2005

 

I see you say the 5 wire is expensive. How much does it cost? I just bought a 5 wire Bosch LSU4.2 from a VW dealer for $54.58.

I'm kind of new to the 5 wire O2 sensor world. what brand does Honda use ?

 

Honda uses the L1H1 or L2H2 NTK sensors - they are money.

 

Heres what You need to do. ur female harness has 7 wires......the 02 sensor itself is 4 wire(green, white, black, and black. You need the female and male harness to the 4 wire 02 sensor. Now. Splice into these wires going from YOUR HX female main harness- Black/white stripe, black, and green wire(i think it has white stripe, but it is the only green wire.) Now The wires coming off the 4 wire 02 sensor female connecter is orange, yellow, white, and green. Heres it how it goes.

Your HX 7 wire female 02 Harness-----4 wire 02 harness

Black/white stripe------------------------orange/yellow BOTH
black wire(solid black)-------------------white
green--------------------------------------green

Hope this helps out.

 

Thanks, I found the Audi Bosch LSU4.2 for a 2002-2003 1.8T was $245.00 the VW 1.8T was $54.58. Same sensor. It is in front of the Cat on those cars. Needed it for the wide band tuner for our 92Si D16Z6 with a GT35R Turbo. They say you can find the LSU4.2 on line for $34.00.

Sorry if I hijacked this thread.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cb7tunerman &raquo;</TD></TR><TR><TD CLASS="quote">Heres what You need to do. ur female harness has 7 wires......the 02 sensor itself is 4 wire(green, white, black, and black. You need the female and male harness to the 4 wire 02 sensor. Now. Splice into these wires going from YOUR HX female main harness- Black/white stripe, black, and green wire(i think it has white stripe, but it is the only green wire.) Now The wires coming off the 4 wire 02 sensor female connecter is orange, yellow, white, and green. Heres it how it goes.

Your HX 7 wire female 02 Harness-----4 wire 02 harness

Black/white stripe------------------------orange/yellow BOTH
black wire(solid black)-------------------white
green--------------------------------------green

Hope this helps out. </TD></TR></TABLE>

HOW?? I appreciate the help but where does the o2 get its signal. The Helms says the white wire is the siganl wire......

HOWEVER what are the symptoms of a bad/not workign oxygen. My car rusn fine, idles fine. Could it be my chip? Another guy said he disabled his oxygen sensor with uberdata. I need to talk to the guy who did mine and see if he did the same. I had my car running and unplugged the oxygen sensor and it still ran fine. I admit, I am not the most knowledgable guy when it comes to oxygen sensor. I will look at wiring like it is quoted in here and if that doesnt work, I will wire directly to the ECU. I wouldnt mind the CEL but I dont want shitty gas mileage and the CEL is also my shift light

 

okay......update...here is what I did follwoing the advice given previously

4 wire plug ........................end location
white/red............................white (signal from original 5 wire location)
grn/blk................................black wire on thermostat housing plug
blk/wht...............................A6 blk/wht wire on ECU plug
yel/blk................................yel/blk on injector 4

now instead of getting just CEL 1, I am now getting CEL 1 (primary o2) and 41 (primary o2 heater)

WTF did I do wrong. I went from one code to two of them

Just so there is no confusion, I am using the 4wire harness side plug from my secondary. The wire colors are different with an OBD1 plug

 

ANOHTER update. I searched more and more and even more and came across an interesting thread. Your IAT in some way is related to your oxygen sensor. Mine was unplugged as I was extending the wires......I plugged it back in....voila....no more CEL 1, I am still getting the CEL 41 heater codethough. I am going to recehck my wirign tomorrow. It should be okay though......the oxygen sensor is working...well at least I am not getting a code. I hope to wrap this up tomorrow. I want to get this straight for us HX guys who want to keep their Y5's and covert to OBD1. I am almost there.

 

WHITE---&gt;D14 (splice wire and join)

GREEN ---&gt;D22 (splice wire and join)

BLACK---&gt;A6 (splice wire and join)

BLACK---&gt;YELLOW/BLACK---&gt;(injectors have 2 wires and one of them is yellow/black. splice one of the yellow/black wires that goes to the injectors and join it with this wire or you can splice the yellow/black wire on the Idle Air Control Valve)

ALL THE COLORS ON THE LEFT SHOULD BE ON THE 4 WIRE OXYGEN SENSOR. IT DOESNT MATTER WHICH BLACK WIRE YOU CHOSE. SPLICE THE WIRES IN THE CONVERSION HARNESS AND JOIN THEM THERE EXCEPT FOR ONE OF THE BLACK WIRES THAT YOU HAVE TO JOIN AT ONE OF THE INJECTORS OR THE IDLE AIR CONTROL VALVE.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ALLMOTORCRX20 &raquo;</TD></TR><TR><TD CLASS="quote">WHITE---&gt;D14 (splice wire and join)

GREEN ---&gt;D22 (splice wire and join)

BLACK---&gt;A6 (splice wire and join)

BLACK---&gt;YELLOW/BLACK---&gt;(injectors have 2 wires and one of them is yellow/black. splice one of the yellow/black wires that goes to the injectors and join it with this wire or you can splice the yellow/black wire on the Idle Air Control Valve)

ALL THE COLORS ON THE LEFT SHOULD BE ON THE 4 WIRE OXYGEN SENSOR. IT DOESNT MATTER WHICH BLACK WIRE YOU CHOSE. SPLICE THE WIRES IN THE CONVERSION HARNESS AND JOIN THEM THERE EXCEPT FOR ONE OF THE BLACK WIRES THAT YOU HAVE TO JOIN AT ONE OF THE INJECTORS OR THE IDLE AIR CONTROL VALVE.

</TD></TR></TABLE>

already got it figured out man. been running good for awhile now

 

anyone have info to help me out with similar situation??
here's a link to my question
https://honda-tech.com/zerothread?id=1520753