HB10 - Check HO2S Integrity

Heated Oxygen Sensor (HO2S) always lean, slow to switch, lack of switching or fuel at adaptive limit could be caused by:

- Moisture inside the HO2S harness connector resulting in a short to ground.

- HO2S coated with contaminants.

- HO2S circuit open.

- HO2S circuit shorted to ground.

- Key "OFF".

- Inspect the HO2S harness for chafing, burns or other indications of damage. Service as necessary.

- Inspect HO2S and connector for indication of submerging in water, oil, coolant, etc. Service as necessary.

- Run engine at 2000 rpm for two minutes.

- Key "OFF".

- Run Key On Engine Running (KOER) Self-Test. Key ON Engine Running (KOER) Self-Test

- Are Diagnostic Trouble Codes (DTC) present?

Yes -- Go to HB11. HB11 - Check HO2S On Engines With MAF Sensor

No -- Go to HB15. HB15 - Check Resistance of Heater Element On HO2S