Oxygen Sensor (O2S)/Heated Oxygen Sensor (Ho2S)
- Start and warm engine to operating temperature. Pull back seal at O2S/HO2S connector. Using a DVOM with at least a 10-megohm input impedance, backprobe O2S/HO2S connector between sensor signal and sensor ground terminal. See Figure .
- Increase engine speed to 2000 RPM and hold for about one minute while watching voltmeter. Reading should fluctuate between zero and one volt, without being constantly high or low. If voltage is not as specified, see CODE 13 in the TESTS W/CODES article.