OE: 250-24675, 250-24253, 25024675, 25024253 Features: Extensively Tested During Manufacture to Guarantee Quality and Reliability Supplied With a Factory-Fitted Connector for Easy Installation Precision manufactured with a sensing element incorporating premier technical ceramics Where are my oxygen sensors located? Diagnostic Trouble Codes (DTC) When oxygen sensor failure occurs, a DTC is recorded in the Engine Control Unit (ECU) and a Malfunction Indicator Lamp (MIL) is illuminated on the dash, alerting the driver the vehicle has a problem. .