you should have at least one of these: code P0 136-abnormal ouput signal, P0137-open circuit or P0138- short circuit. check your wiring first. the black wire (terminal 2) should have battery voltage against ground, the pink wire computer (terminal 1) grounding (heater driver), the shielded white (terminal 4) AF (--), shielded black wire (terminal 3) AF (+). with the connector to HO2S disconnected, check the resistance between terminals 1 and 2 of the sensor ( not the harness) the resistance should be between 1.8-3.4 ohms at about 20 degrees celsius, between terminals 1 and 4 should have 10k ohms or higher.