What does Error Code P0140 mean?
Moderate Issue
DTC Code P0140 indicates that the O2 Sensor Circuit for Bank 1 Sensor 2 is not showing any activity. This occurs when the voltage signal from the sensor to the Engine Control Module (ECM) remains constant, suggesting a lack of response in monitoring the oxygen levels in the exhaust gas.
What are the symptoms of Error Code P0140?
- Engine Light ON: The check engine light or service engine soon warning light illuminates, indicating an issue with the O2 sensor circuit on Bank 1 Sensor 2.
- High Fuel Consumption: The vehicle may experience increased fuel consumption due to improper air-fuel mixture caused by the lack of activity in the O2 sensor circuit.
- Excessive Smoke from Exhaust: There may be excessive smoke emitted from the exhaust, which can be a result of an incorrect air-fuel ratio due to the O2 sensor circuit not detecting activity.
What causes Error Code P0140?
- The rear heated oxygen sensor on Bank 1 may be faulty, leading to no activity detection.
- An open or shorted harness in the rear heated oxygen sensor on Bank 1 can disrupt the circuit.
- Poor electrical connections in the rear heated oxygen sensor circuit on Bank 1 can cause signal loss.
- Inappropriate fuel pressure can affect the sensor's ability to detect activity.
- Faulty fuel injectors may lead to incorrect air-fuel mixture, impacting sensor readings.
- Intake air leaks can alter the air-fuel ratio, affecting sensor performance.
- Exhaust gas leaks can cause incorrect readings by the oxygen sensor.
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How to fix Error Code P0140?
- Verify DTC Code: Confirm the presence of DTC P0140 using an OBD-II scanner. Ensure no other related codes are present.
- Inspect Wiring and Connectors: Visually inspect the wiring and connectors for the Bank 1 Sensor 2 O2 sensor. Look for signs of damage, corrosion, or disconnection.
- Check Sensor Voltage: Use a multimeter to measure the voltage at the O2 sensor connector. The voltage should fluctuate between 0.1V and 0.9V. A constant reading indicates a faulty sensor or circuit.
- Test Sensor Heater Circuit: Verify the heater circuit of the O2 sensor is functioning. Measure the resistance of the heater circuit; it should be within the manufacturer's specifications.
- Replace O2 Sensor: If the sensor is faulty, replace the Rear Heated Oxygen Sensor Bank 1. Clear the DTC code and test drive the vehicle to ensure the issue is resolved.