Just curious... i have done a obd0 to obd1 swap in my 89 prelude with a b20a. The car originally was obd1 and is now obd2 with the new motor. I have a ecu conversion harness for the new obd1 ecu. I am having problems with code 41, (heater circuit) The new motor has a single, 4 wire o2 sensor on the downpipe before the cat. The engine harness is obd1, however the shock tower harness that leads into the car is still obd0, hence the conversion harness. I have a o2 sensor plug that i soildered all four wires too inorder to wire it directly to the ecu. All four wires are taped up toegether and run from the 02 sensor through the fire wall and direcly to the ecu. However, im still getting a code 41 , even with a brand new OEM 02 sensor. Any recommendations?? any specific type of wire i should have used?? This problem is driving me nuts! Please help.