Oxygen (O2) Sensor Current Feed & Heater Resistance
- Connect voltmeter between ground and terminal No. 1 of 2-wire connector located next to firewall. Voltage reading should be battery voltage. Remove ground wire from fuel injection ECU terminal No. 20.
- Connect ohmmeter between oxygen sensor harness terminal No. 2 (Black wire) and ground. Connector is located next to firewall. With a cold oxygen sensor, resistance should be 2-3 ohms. With a oxygen sensor warmer than 660°F (350°C), resistance should be 7-14 ohms. Replace oxygen sensor as necessary.