P0063 OBD-II Trouble Code: HO2S Heater Control Circuit Low (Bank 2 Sensor 3)

P0063 trouble code definition

Trouble code P0062 indicates that the heater element used to heat up an oxygen sensor has malfunctioned. To switch on an oxygen sensor either a power or a ground is supplied to the sensor. A good ground connection and a voltage ranging from 12.0-13.5 are needed to operate the oxygen sensor.

The cause of the code is commonly due to the lack of either voltage or adequate ground supply. Each are equally important to successfully heat the oxygen sensor to its required operating temperature. An oxygen sensor is designed to work around 600-800 degrees Fahrenheit. With any other temperature than that, an oxygen sensor will not be able to accurately read the air-fuel ratio of the engine. Nor will it be able to log the amount of harmful pollutants that are being created by the engine.

What the P0063 code means

The code is commonly due to a low amount of voltage signal being sent from the oxygen sensor to the PCM. The PCM sends a voltage to the heater circuit of the oxygen sensor to warm it up to a desirable temperature.The sensor will emit to the PCM a certain resistance and voltage according to the amounts of gasses and air that the sensor is picking up.

The PCM will take the readings of the oxygen sensor to determine if the air-fuel ratio of the engine is within the desirable range of 14.7:1. If the voltage being sent by the oxygen sensor is lower than that of the PCM’s desired range, code P0063 will set. If the code sets there is a low voltage being emitted by the oxygen sensor.

What causes the P0063 code?

  • An internal oxygen sensor circuit fault

  • High resistance or voltage consumption of the heater element inside of the oxygen sensor

  • A frayed wire, corroded connection, exposed or open wiring

What are the symptoms of the P0063 code?

  • Usually there are no symptoms besides a Check Engine Light being set.

  • In rare cases the vehicle may struggle to idle or hesitate to accelerate.

How does a mechanic diagnose the P0063 code?

  • Back probes the oxygen sensor to compare the readings to manufactures specifications

  • Checks the related wiring and connections of the oxygen sensor

Common mistakes when diagnosing the P0063 code

  • Not checking for blown fuses

  • Replacing the sensor before cleaning the electrical contacts then remeasuring

  • Replacing the sensor without measuring the outputs of the sensor, such as volts and resistances.

How serious is the P0063 code?

  • The code will increase the amount of pollutants being emitted into the atmosphere.

  • Also increases the amount of fuel consumption which is harmful to the environment.

  • An increase in fuel consumption will affect how much you pay at the pump.

What repairs can fix the P0063 code?

  • Replacing the oxygen sensor will most likely clear the code
  • Repairing or replacing of the damaged or oil saturated wiring and connections
  • Replacing the PCM
  • Reprogramming of the PCM (if applicable)

Additional comments for consideration regarding the P0063 code?

Always measure the voltage output and resistance of the oxygen sensor and compare it with the manufactures specifications

Need help with a P0063 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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