Sensor Heating Element Test

NOTE: This test should be performed only after basic inspection, and ignition and fuel systems inspections are passed.

NOTE: Only use a high input impedance Digital Volt Ohm Meter (DVOM) when testing components on computerized vehicles.

NOTE: Verify DVOM is set to read OHMS only (not volts). Verify external voltage is not applied to the sensor lead, as inaccurate results will occur.


1. Disconnect the oxygen sensor(s) electrical connector from the wiring harness
2. Connect DVOM across terminals 3 and 4 of the sensors electrical connector. Set to read OHMS.
3. Resistance value should be between 5 and 7 ohms.
4. Replace the sensor if the resistance reading is not within the previous specifications or if the ohmmeter indicates infinite resistance.