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 temperature greater then 170 °F, in closed loop.

SET CONDITION
If oxygen sensor voltage stays between 0.29V and 0.72V for 30 sec, 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 oxygen sensor ground circuit open
- PCM connector observable defect
- 1/2 O2 sensor defective
- PCM defective