02 Sensor issues after engine swap.

K-Series Programmable ECU installation questions / support issues
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02 Sensor issues after engine swap.

Post by token »

I have a 05 Honda Civic SI EM2 with a k20a type r dc5 engine with kpro on the jdm ecu. Last fall i pulled the engine for a winter rebuild. When I dropped the exhaust manifold I forgot to unplug my hybrid racing 02 harness. The wires on the harness side pulled out from the plug. When I parked the car last fall I had absolutely no engine codes. Never had an 02 problem. I found a diagram online for the plug but I think it was wrong and I had the wires pinned incorrectly for a day. I found an actual picture of the harness online and re pinned it correctly but I am still getting P1166. When I checked the relay for the 02 sensor the white wire for 02 power (pin 87 on the relay) is a bit deformed as if it got hot. I replaced the relay which is clicking fine with engine running/ignition on cranking.
I tested the heater circuit on the oxygen sensor itself and I am getting 1.3 ohms of resistance.
Is it possible the ECU circuit is fried or should I try to replace the sensor?

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Re: 02 Sensor issues after engine swap.

Post by Spunkster »

You should try the ECU on a known working vehicle to see if it is working correctly. This is the only way you will be able to tell if it is the ECU or something that is in the vehicle causing the issue.

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