Oxygen sensors (O2 sensors) play an essential role in keeping your engine running smoothly.
The primary function of an O2 sensor is to monitor the levels of oxygen in the exhaust gases and inform the engine control module (ECM) of any imbalances.
An O2 sensor code P0139 indicates that the ECM has detected a high voltage signal from the bank 1 sensor 2 O2 sensor circuit.
What is P0139 O2 Sensor Circuit High Voltage?
P0139 is a diagnostic trouble code (DTC) that indicates a high voltage signal from the bank 1 sensor 2 O2 sensor circuit.
It means that the O2 sensor is sending a signal to the ECM that indicates that the level of oxygen in the exhaust gases is too high.
This can cause various problems with the engine, including decreased performance and increased emissions.
Causes of P0139 O2 Sensor Circuit High Voltage
There are several possible causes of P0139 O2 Sensor Circuit High Voltage. These include:
- Faulty O2 sensor
- Wiring issues
- ECM issues
- Vacuum leaks
- Malfunctioning catalytic converter
- Exhaust leaks
Symptoms of P0139 O2 Sensor Circuit High Voltage
The most common symptoms of P0139 O2 Sensor Circuit High Voltage include:
- Check Engine Light (CEL) is on
- Decreased fuel economy
- Rough idling
- Poor acceleration
- Increased emissions
- Failed emissions test
Diagnosis of P0139 O2 Sensor Circuit High Voltage
To diagnose P0139 O2 Sensor Circuit High Voltage, the following steps need to be taken:
- Check the O2 sensor wiring and connections.
- Test the O2 sensor voltage and resistance.
- Check the ECM for any faults or malfunctions.
- Test the catalytic converter for proper function.
- Check for any vacuum leaks or exhaust leaks.
How to Fix P0139 O2 Sensor Circuit High Voltage
The following steps can be taken to fix P0139 O2 Sensor Circuit High Voltage:
- Replace faulty O2 sensor.
- Repair or replace damaged wiring.
- Replace the ECM if necessary.
- Repair any vacuum leaks or exhaust leaks.
- Replace catalytic converter if faulty.
Prevention of P0139 O2 Sensor Circuit High Voltage
Preventing P0139 O2 Sensor Circuit High Voltage involves regular maintenance and inspection of the vehicle. This includes:
- Regularly scheduled tune-ups
- Replacing the O2 sensors as recommended by the manufacturer
- Regular inspection of the exhaust system
- Fixing any vacuum leaks or exhaust leaks as soon as possible.
Conclusion
P0139 O2 Sensor Circuit High Voltage is a common problem that can cause decreased engine performance and increased emissions. It is important to diagnose and fix this issue as soon as possible to prevent further damage to the engine.
FAQs
- What is the function of an O2 sensor?
An O2 sensor measures the level of oxygen in the exhaust gases and informs the ECM of any imbalances.
- What causes P0139 O2 Sensor Circuit High Voltage?
Possible causes include a faulty O2 sensor, wiring issues, ECM issues, vacuum leaks, malfunctioning catalytic converter, and exhaust leaks.
- What are the symptoms of P0139 O2 Sensor Circuit High Voltage?
Symptoms include decreased fuel economy, rough idling, poor acceleration, increased emissions, and failed emissions test.
- How is P0139 O2 Sensor Circuit High Voltage diagnosed?
Diagnosis involves checking the O2 sensor wiring and connections, testing the O2 sensor voltage and resistance, checking the ECM for any faults or malfunctions, testing the catalytic converter for proper function, and checking for any vacuum leaks or exhaust leaks.
- How is P0139 O2 Sensor Circuit High Voltage fixed?
Possible fixes include replacing the faulty O2 sensor, repairing or replacing damaged wiring, replacing the ECM if necessary, repairing any vacuum leaks or exhaust leaks, and replacing the catalytic converter if faulty.
