P0140

Tests 1 - 2:

Tests 3 - 7:

Tests 8 - 9:

SYMPTOM
P0140 - 1/2 O2 SENSOR STAYS AT CENTER

WHEN MONITORED
With the vehicle engine running for more than two minutes, engine coolant temperature greater then 170 °F, in closed loop.

SET CONDITION
If oxygen sensor voltage stays between 0.29 volts and 0.72 volts for 30 seconds, the PCM pulls the sensor voltage to 5.0 volts for 60 seconds and monitors the sensor voltage. If the voltage stays at 5.0 volts, this trouble code will set, indicating no activities.

POSSIBLE CAUSES
- 1/2 O2 sensor connector observable defect
- 1/2 O2 sensor signal circuit open
- 1/2 O2 sensor ground circuit open
- 1/2 O2 sensor defective
- PCM connector observable defect
- PCM defective