Long story short My 00 Si has the obd2a dash harness. The current engine harness i'm using is a POS (previous owner) I have the option of getting a 97 HX M/T harness for $70 which beats buying a obd2a ex harness for $200. I've tried to find what is different from the 2 engine harnesses but couldn't. Does anyone know what would need to be modified so I don't have a CEL. The ecu I'm using is a obd2a p72

 

only ones i can think of is there is an EGR valve and no knock sensor on the hx.

 

you could try running the right ECU, assuming you have a b16a. You need to specify what engine you have though.

 

Says right in the title...b18c1

x2 with kyden

 

Crap, I am stupid

 

Is the current harness causing the CEL?

 

No your not.....


OP, what cel code(s) is it throwing?

 

Thanks for all the quick replies. The cel codes are P0118, P0122, P1337, P0113.
Another thing that bothers me is that there is no knock sensor or any o2 sensors hooked up but the only codes I'm getting are the ones i posted. Probably should have mentioned that at the moment the motor in the car is a jdm b16 as the gsr is getting a rebuild.

 

I'm not stupid!

 

Primary O2 sensor wiring is also different on the HX harness.

 

No your not, but that swap will be a gsr once the machine shop finishes my block.
You are correct the HX has a 5 wire wide band O2. Could I still make it work?

 

Yes, absolutely. You'll need to compare an HX pinout to any other '96 - '98 trim level and move some stuff around and cut the HX O2 sensor plug off and solder on a 4 wire plug.

 

Not all hx's are 5 wire. Only the 5 speeds. The ex harness is what you need. Unless you can read schematics/pin outs and solder. Even then I'd say you will have a couple hours work in modifying the hx harness.

 

Well I just bought a obd2a ex m/t engine harness off ebay for $160. Any thoughts on why I'm not getting mil codes the o2 sensor's or knock sensor?

 

You really should have gotten a 99-00. The OBD2a engine harness has 3 plugs and the OBD2b has 2 (and one incorporated into the dash harness). You're going to have a heck of a time trying to repin everything.



As far as your codes go the problem you're probably having is swapped around connectors or lack of sensors (ECT/TW, TPS, CKF, IAT) which getting a new harness won't fix. Is your B18C obd1 or 2? If its OBD1 then there's half your issue right there. The OBD1 B18C1 doesn't have a CKF sensor so you'll have to bypass it. Also the IAT is round and not square like the car's harness you have now so you'll have to swap connectors to plug it it. Your ECT/TW sensor wire either isn't plugged in or the wires have pulled out. You also either has a broken TPS or the TPS and MAP wires are swapped. Here are some pictures of the sensors check and confirm what I said above:

 

He stated in the OP that he's using an OBD2A dash harness as well.

 

Out of curiosity why does the car have an OBD2A dash harness?

 

Either way I don't think a new engine harness will magically fix those CELs. Oops missed the op that it is an obd2 dash harness but can the op confirm that with a pic?

 

I'm sure it's obd2a but ill upload a picture. The car is a theft recovery and had a d16y8 when i bought it. I let my buddy borrow my harness when we swapped motors and he sold the car before i could take it back. I understand some modifications will need to be done also i live in CA were there is emssion control so i cant have any mil codes. The motor i will be running is a obd1 b18c1 with obd2a p72 ecu.

 

Thanks for posting this, I't will be of great help when I get the new harness. Also Yes the TPS is broken but not broken off. If it will still throw a code once I get everything rewired I will probably just replace it. Any thoughts on what I could do about the GSR IAB (secondery butterfly)?