P0063 Fault Code

P0063 OBD-II Trouble Code Short Description

HO2S Heater Control Circuit Low (Bank 2 Sensor 3)

What does trouble code P0063 mean?

Error code P0063 refers to the HO2S (Heated Oxygen Sensor) Heater Control Circuit Low for Bank 2 Sensor 3. This code indicates a problem with the electrical circuit that controls the heater for the third oxygen sensor on the second bank of the engine.

The purpose of the oxygen sensor heater is to warm up the sensor quickly after the engine starts, which allows for more accurate readings. The heater circuit uses power from the vehicle's electrical system to warm up the sensor.

When the Powertrain Control Module (PCM) detects that the voltage in the heater circuit is too low, it triggers the P0063 error code. This could be due to a faulty oxygen sensor heater, a short circuit in the wiring, or a problem with the PCM itself.

To diagnose and fix this issue, a technician will typically perform the following steps:

  1. Inspect the wiring and connector: The technician will examine the wiring and connector for signs of damage, loose connections, or corrosion. They may also use a multimeter to check the electrical resistance in the circuit to determine if there is a short or open circuit.

  2. Check the oxygen sensor heater: The technician will test the oxygen sensor heater to ensure it is functioning properly. They may use a voltmeter or an oscilloscope to measure the voltage and waveform of the heater circuit.

  3. Test the PCM: If the wiring and oxygen sensor heater are working fine, the technician may need to test the PCM to ensure it is sending the correct signals to control the heater circuit. This requires specialized diagnostic equipment.

Once the exact cause of the problem is identified, the necessary repairs or replacements can be made. This may involve repairing or replacing damaged wiring or connectors, replacing a faulty oxygen sensor, or reprogramming or replacing the PCM if necessary.

It is important to address this issue promptly, as a malfunctioning oxygen sensor heater can affect the performance and emissions of the vehicle. Additionally, unresolved P0063 codes may prevent the vehicle from passing emissions tests.

It is recommended to have a professional technician diagnose and repair the P0063 error code, as they have the expertise and equipment to properly address the underlying issues.


What are the symptoms of the P0063 code?

When experiencing the P0063 fault code, the following symptoms may occur:

  • Check Engine Light (CEL) or Malfunction Indicator Lamp (MIL) illuminated
  • Decreased fuel efficiency
  • Rough idling or stalling
  • Engine misfire
  • Lack of power or reduced acceleration

It is important to note that these symptoms may vary depending on the make and model of the vehicle. It is recommended to consult with a professional mechanic or use a diagnostic scanner to properly diagnose and address the issue.


What causes the P0063 code?

The P0063 fault code is related to the HO2S (Heated Oxygen Sensor) heater control circuit on Bank 2 Sensor 3. This code indicates that the heater control circuit voltage is lower than normal or below the minimum threshold.

Possible causes of the P0063 fault code include:

  1. Faulty HO2S heater control circuit: There may be a problem with the wiring, connector, or internal component of the Bank 2 Sensor 3 HO2S heater.

  2. Open or short circuit: The circuitry connecting the HO2S heater to the power source or the PCM (Powertrain Control Module) might have an open or short circuit, which is causing low voltage.

  3. Faulty PCM: The PCM, which controls the HO2S heater circuits, could be malfunctioning and not supplying enough voltage to the heater.

  4. Electrical issues: Other electrical problems, such as a blown fuse, damaged wiring, or a faulty relay, can also result in the P0063 fault code.

It is recommended to diagnose and address the underlying cause of the fault code to rectify the issue. A thorough inspection of the related components and their wiring is necessary to determine the exact cause and proceed with the necessary repairs or replacements.

Possible Solutions

How to fix P0063?

The P0063 fault code refers to the HO2S (Heated Oxygen Sensor) Heater Control Circuit Low for Bank 2 Sensor 3. This means that the control circuit for the heater in the oxygen sensor located in bank 2, sensor 3 is reading a low voltage.

To fix this fault code, you can follow these steps:

  1. Check the wiring: Inspect the wiring harness connected to the oxygen sensor. Make sure there are no loose or damaged connections, and check for any signs of fraying or exposed wires. Repair or replace any damaged wiring as necessary.

  2. Test the oxygen sensor: Use a multimeter to test the oxygen sensor's heater circuit. Measure the resistance across the heater element terminals. Compare the reading to the specifications provided by the vehicle manufacturer. If the resistance is too low or too high, replace the oxygen sensor.

  3. Check the fuse: Locate the fuse that is responsible for powering the oxygen sensor heater circuit. Consult the vehicle's manual to find the exact location of the fuse. If the fuse is blown, replace it with a new one of the same rating.

  4. Inspect the oxygen sensor relay: Some vehicles have a relay that controls the power supply to the oxygen sensor heater circuit. Check the relay for any signs of damage or malfunction. Replace the relay if necessary.

  5. Clear the fault code: After performing the necessary repairs, use an OBD-II scanner to clear the fault code from the vehicle's computer. This will reset the system and allow you to monitor if the fault code reoccurs.

Note: If you are uncertain about any of these steps or lack the necessary tools and experience, it is recommended to consult a professional mechanic for proper diagnosis and repair.