Checking Oxygen Sensor Heater

SYMPTOM
CHECKING OXYGEN SENSOR HEATER

POSSIBLE CAUSES
- 1/2 02 sensor voltage between 0.4 V & 0.6 V
- 1/1 02 sensor defective
- 1/2 02 sensor defective
- ASD relay output circuit open (1/1 02 sensor)
- ASD relay output circuit open (1/2 02 sensor)
- Heater ground circuit open (1/1 02 sensor)
- Heater ground circuit open (1/2 02 sensor)