Oxygen Sensor: Testing and Inspection

1. Start and operate engine until coolant reaches normal operating temperature.
2. Stop engine and remove oxygen sensor wire from connector, then separate connector from oxygen sensor.
3. Start engine and, using a suitable voltmeter, check that voltage from oxygen sensor exceeds .7 volts when engine speed is kept at 3,000 RPM or higher.
4. With engine at idle, check that voltage at oxygen sensor is at ``0'' volts when vacuum hose is disconnected from gas filter.
5. Install oxygen sensor connector, then clamp wire.