Exhaust Gas Oxygen (O2) Sensor

O2 sensor is mounted in the exhaust pipe just below the exhaust header. Use a high impedance DVOM (10 Megohm, minimum) to measure the voltage between pigtail connector and ground. A "Scan" tester may be used to measure voltage when in closed loop. Ensure engine is at normal operating temperature. Run engine for 40 seconds (minimum) and measure voltage. Voltage should be 0.1-1.0 volt. If not, replace sensor.