Throwing this one out there... feel free to throw your 2 cents in. This is a 97 DX civic. D16y7 5speed OBD2a. stock Throwing CEL code 1. This is trouble with primary 02 sensor. (Tried swapping with known good 02 sensor and same trouble code.) (Checked continutiy from the o2 sensor terminal to the ecu,. Good) Typically an ECU will throw an 02 sensor code after then engine has started and approaching normal operating temperature. If fault is present at this point the trouble code appears. In this situation, even after the ECU is reset and prior to starting the engine this code is present immediately after the ignition is switched to the on position. What are your thoughts Hondaswap pers?