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P0144 OBD-II Trouble Code: O2 Sensor Circuit High Voltage (Bank 1, Sensor 3)

Check Engine Light

P0144 code definition

O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)

What the P0144 code means

P0144 is the OBD-II generic code which indicates that the Engine Control Module (ECM) has detected excessively high voltage from the bank 1 sensor 3 O2 sensor circuit, indicating a rich condition.

What causes the P0144 code?

  • The O2 sensor bank 1 sensor 3 is the sensor after the last catalyst. A rich condition may be a problem with the catalyst not cleaning the exhaust. This can be caused by a broken up catalyst.

  • The ECM detects a short to power in the circuit for the O2 from a wiring or sensor problem.

What are the symptoms of the P0144 code?

  • The code will cause the ECM to turn on the check engine light.

  • The ECM does not use this sensor for fuel control but for a catalyst monitor only and should not cause a direct impact on the engine performance.

How does a mechanic diagnose the P0144 code?

  • Checks the electrical connections or wire harness cover to the O2 bank 1 sensor 3 for shorts or sensor damage

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

  • Monitors O2 sensor data to see if the voltage is stuck above 500 mV

  • Checks the exhaust catalyst for damage or if it broke apart in the housing

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

Common mistakes when diagnosing the P0144 code

Follow these simple guidelines to prevent mistakes:

  • Check the catalyst integrity for any damage before replacing the O2 sensor

  • Check the O2 sensor for oil or coolant contaminants that may short the sensor from engine leaks

  • Scan the replacement O2 sensor to make sure the heater circuit works properly

  • Check the removed O2 sensor for damage from a defective catalyst that will cause sensor failure

How serious is the P0144 code?

  • The code may cause the engine to fail emission testing.
  • The code may indicate a problem with the catalyst and it may block the exhaust.

What repairs can fix the P0144 code?

Additional comments for consideration regarding the P0144 code

The O2 sensor signal circuit for bank 1 sensor 3 is used to monitor the catalyst efficiency and does not affect the fuel control of the engine.

Need help with a P0144 code?

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