P0150 code definition

O2 Sensor Circuit Malfunction (Bank 2 Sensor 1)

What the P0150 code means

P0150 is the OBD-II generic code indicating the O2 sensor 1 for bank 2 fails to meet the minimum or maximum voltage limits calibrated into the Engine Control Module (ECM).

What causes the P0150 code?

  • The ECM monitors the O2 sensor’s highest and lowest voltages. In the case of the P0150 code, the voltages coming from the O2 sensor are not within specifications.

  • The ECM detects a voltage problem and turns on the Check Engine Light.

  • Exhaust leaks in front of the sensor cause an erratic reading from the sensor.

What are the symptoms of the P0150 code?

  • The engine may run excessively rich if the engine goes into an open loop.
  • The engine may start to misfire if the spark plugs get fouled out over time.
  • The Check Engine Light will be illuminated.
  • You may have exhaust leaks at the manifold or the connection at the header pipe.

How does a mechanic diagnose the P0150 code?

  • Scans codes and documents freeze frame data, then clears codes to verify failure

  • Monitors O2 sensor data for the voltage to be switching back and forth between .2 volts and 1.2 volts, and replaces the sensor if not within specifications

  • Checks the O2 sensor wiring and the harness connections for any corrosion. Repairs or replaces any connections with problems

  • Checks the exhaust for leaks before the sensor and repairs any leaks that can cause the sensor to be affected from the leak

  • Follows the manufacturer's specific pinpoint tests for further diagnosis

Common mistakes when diagnosing the P0150 code?

Follow these simple guidelines to prevent mistakes:

  • Fix exhaust leaks before the sensor to prevent incorrect readings.

  • The O2 sensor may be getting oil or coolant contaminants and should be fixed before the O2 sensor is replaced.

  • Repair any harness that is damaged properly - without taking shortcuts - to prevent a failed circuit.

How serious is the P0150 code?

  • An exhaust manifold leak can cause the O2 sensor to think there is too much oxygen in the exhaust and the ECM will enrichen the mixture to compensate, thus using excessive fuel.

  • The O2 sensor may not read correctly if the exhaust leaks in front of the sensor.

  • The ECM may stay in open loop until the O2 system is repaired or the O2 sensor starts working again, causing extended rich conditions that could possibly damage other engine components.

What repairs can fix the P0150 code?

  • Replacing the O2 sensor for bank 2 sensor 1
  • Repairing or replacing the wiring or connection to the O2 sensor for bank 2 sensor 1
  • Repairing exhaust leaks at the manifold for bank 2

Additional comments for consideration regarding the P0150 code

The O2 sensor circuit for bank 2 sensor 1 is used to give a voltage feedback to the ECM to control the fuel-to-air ratio for the bank 2 of the engine.

Need help with a P0150 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230 to have this issue resolved.

This article originally appeared on YourMechanic.com as P0150 OBD-II Trouble Code: O2 Sensor Circuit Malfunction (Bank 2, Sensor 1) and was authored by Jay Safford.


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