Also, this is one of my threads on the subject, though it doesnt help that much since the images are broken. Still looking for them to repiar.

https://www.evolutionm.net/forums/in...sting-ecu.html

Here are a bunch of docs I kept while doing that troubleshooting.

attachment.pdf

Evo 9 ECU.pdf

Evo 9 USDM ECU pinout.pdf

evo ix pinout.pdf

 

amazingl response. I will do my best!

 

So are 1 & 2 grounds? And does 4 go to ecu pin 3?

None of these tests led me to conclude anything except it was hard to get a good ohm reading between 1-3 but when it did work it was under 20. I cut the 02 sensor plug off and hardwired the connection for fear of the plug being bad.

This Didn't solve anything though

Ecu pin 3 heater control ecu pin 71 sensor wire
So those are likely 4 and 3 respectively.


This drivin me nuts

 

I don't know or remember if they are grounds. You'll just want to confirm what color wire goes to 3 and 71 on the ECU, so make sure which is which. I assume you already have the ECU free and available if you did the resistance test from the plug to the ECU. That test will require a multimeter and a bit of wire to extend, so you can meter from near under the dash and the plug. This is how I found that that the wire was damaged.

However, in the docs I linked in the previous thread you can see the color coding which is/was the answer for colors on my end.

The White is pin 71 ad the Blue/Red Stripe is pin 3.

Check for continuity of the harness by connecting a meter up to either end of those wires. One end on the while wire in the plug at valve cover (unplugged from 02), and one wire on the plug end by the ecu, and then you'll know if the wires are whole.

 

Further more the ecu Pinout calls for a wire in pin 2 which is absent should be an injector wire.

 

Are you sure you are not looking at 72 and not 2. Maybe getting the plugs mixed up when unplugging them, and looking at the backwards?

72 is not in use.

I am logging right now so I don't want to take the ECU out to confirm (It my afternoon I can actually do a couple of pulls). But, I seem to remember my wiring following exactly the docs I had. I did however frequently consure which plug was which, so I finally put a big fat marker with tape on them.

 

ill double check. was the color of the wire at the ecu the same as the color on the o2 plug?

 

ok in my haste I pricked the green wire not inverting the wiring diagram to compensate for the ECU connector. Obviously its the blu with purple wire. I will have to make a jumper for this to see if it solves my issue. Thanks a lot for helping me get this far. I will know tomorrow. If I can get my o2 sensor to work, Im going back to MAF ASAP and focusing on my SAS/factory ALS thread!

 

OK, remember too, from one of my other posts on this stuff, one of those wires, pin 71 I think is wrapped in a shielding wire. The big fat wire is Green from my recollection, and it has the other one running through it. It is also weird, as you should see it with a bare end if you uwrap the wiring loom a bit. In my other posts, that was my initial question, "Is this correct?" and several stated they are all the same. however you could still trace from the pins to the plug in the manner above.

Let me know how it goes.

 

i thought that was the knock sensor wire that was shielded? Man, too many wires Ill have to check for sure.

 

Oh Crap. Now I'm not sure. I also replaced the knock sensor a long time for another troubleshooting issue. I actually think I did that before I found it was the wiring of the o2.

I am going to check my old threads, because I show it with a pic...

 

OK, found at least one of my threads where I talk about that, and YES, you are correct. That shielded business is for the knock sensor. Sorry about making it more confusing. My memory sucks. Too much 'fun' in college I think, erased most of any ability to remember stuff.

https://www.evolutionm.net/forums/ec...ck-sensor.html

Post 12 confirms you were right. never mind .

 

Can u snap a pic of the sensor side of the Plug?

 

You mean of the plug that wires in the sensor itself? Its an after market replacement, so those wires beyond the valve cover are no longer factory colors. It just has a factory connecting harness.

Or, do you mean another pic facing the disconnected plug. Give me an example pic if you have it, and I will copy that.

 

Idk I jumped the blue wire to the ecu blue with tracer and cel still there . Second brand new sensor I'm at a loss.

I have the fsm and I was simply looking for something that would show the connections between the ecu conn to the 02 connector.