1. Home
  2. /
  3. Complete List of OBD2...
  4. /
  5. P0150 Code – What...

P0150 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


In order to identify specific issues in each component, DTC codes are alphanumeric symbols that make up the diagnostic OBD system of a vehicle. P0150 is a DTC related to the O2 sensor circuit in Bank 2, Sensor 1, and it’s also known as an upstream O2 sensor. This sensor will play an important role in monitoring the oxygen levels of exhaust gases prior to entering a catalytic converter.


The P0150 code indicates that on Bank 2, the voltage in the upstream O2 sensor is too low. In particular, it is found that the voltage output does not correspond to the expected range. The difference may be due to a number of factors affecting the ability of the sensor to provide accurate readings.


  • One of the main reasons for the P0150 code is an upstream O2 sensor that is not working properly. Voltage measurements can become erroneous as a result of dirty or worn-out sensors.
  • Problems with the wire or connections: The upstream O2 sensor’s functioning may be hampered by corroded or damaged wiring and connectors.
  • Mechanical concerns with the engine: Any problems that result in an unbalanced air-fuel combination, including a vacuum leak or a broken fuel injector, will affect the O2 sensor’s results.


  • Check Engine Light On: The most obvious symptom of the P0150 code is the Check Engine Light turning on the dashboard of the car.
  • Reduced Fuel Efficiency: An upstream O2 sensor issue might result in inappropriate fuel mixture regulation, which lowers fuel efficiency.
  • Problems with engine performance: Due to inaccurate sensor readings, your engine may have less power, a rough idle, or trouble starting.


The P0150 code has to be diagnosed using a methodical process:

  • OBD-II Scanner: A skilled mechanic will access the vehicle’s Engine Control Module (ECM) with an OBD-II scanner to extract the recorded DTCs.
  • Visual Inspection: To check for any obvious damage or problems, the technician will visually examine the upstream O2 sensor, its cabling, and its connections.
  • Sensor testing: Under varied engine circumstances, specialized diagnostic instruments may be utilized to examine the voltage output and responsiveness of the upstream O2 sensor.
  • Cross-checking: To validate the problem, the technician may contrast the sensor readings with the predicted values and the data from the O2 sensor farther downstream.

Common mistakes

  • Replacing the O2 sensor without confirmation of the root cause because it could be another factor, such as an electrical malfunction or engine failure, that caused the code. 
  • A lack of attention to the monitoring of associated trouble codes, which could give further insight into the problem.

How serious is this?

Although the code P0150 does not present an immediate and serious problem with drivability, it should not be ignored. If the downstream O2 sensor is not functioning properly, there may be an increase in emissions and a loss of fuel efficiency, as well as the potential for more serious problems over time that need to be addressed.

What repairs can fix the code?

repair manuals

  • O2 Sensor Replacement: If the upstream O2 sensor is shown to be defective, the problem can be fixed by replacing it with a brand-new, high-quality sensor.
  • Repairing wires or connections: Correct signal transmission can be achieved by addressing any corroded, damaged, or attached wires and connections.
  • Repairing mechanical issues with the engine: The O2 sensor will give more accurate readings if mechanical faults with the engine that impact the air-fuel combination are located and fixed.

Related codes

  • P0146: O2 Sensor Circuit Signal Stuck Rich (Bank 1, Sensor 3)
  • P0147: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 3)


The P0150 DTC code relates to the O2 sensor at Bank 2 and indicates a voltage malfunction in its circuit. Car owners and mechanics are empowered to take appropriate action if they recognize the meaning, cause, symptoms, or possible repair of this code. It can help to maintain the best engine performance, fuel efficiency, and emission control when a problem is promptly diagnosed and resolved.

A trained technician is essential for the efficient resolution of the problem, which ensures the smooth and effective operation of your vehicle if the P0150 code or suspected problems with O2 sensors are encountered.

P0150 Code – What Does It Mean & How To Fix It