I have a 94 civic with a B18A1 swap with a S80 tranny. I have a PR4 ecu that I am running but I wanted to switch to a P75. I purchased a virgin P75 from a guy on here who "claims" it works..... When I plug it in I get a code 41, o2 sensor heater. I currently have a 4 wire just like the P75 uses and I don't get this code with my PR4. I have tested the heater circuit and its fine. No problems in the wiring back to the ecu. Is there anything I am missing. Is this not just a simple ecu swap? Is the P75 ecu bad.....??????? Thanks.

 

I have another ecu comming. Hopefully this will tell me.

 

Well turns out the ecu I bought off the guy on here was bad. I put in the new one and the car runs great. Idle problems were solved and everything. Didn't get my money back but oh well.