Description of DTC code P0056

Oxygen (O2) Sensors are used to control the oxygen concentration in the exhaust gases. The information is used by the vehicle computer to control the air/fuel mixture of the engine. The O2 Sensor makes a comparison between the amount of oxygen present in the exhaust with the air in the atmosphere. This information is sent as voltage to the PCM to control the injector pulse, based on the value obtained from the sensor.

Each sensor has a heating element whose function is to increase the operating temperature in a shorter time. Thus, the PCM uses the input signals earlier for more precise fuel control and reduced emissions.

In this case, the DTC code P0056 OBDII refers to the Sensor number 2 located in bank 2, which is located behind the Catalytic Converter (TWC) and monitors the efficiency of the converter. It does this by checking the oxygen content in the exhaust as it goes out of the converter. The PCM monitors the heater circuit and turns on the Check Engine light once it finds a fault in the circuit.

Symptoms of fault code P0056

  • MIL (Engine Malfunction) light on.
  • No visible symptoms will be present because this sensor is used to check the effectiveness of the TWC.

Causes of OBD2 P0056

The reasons for setting the error code P0056 OBD2 are as follows:

  • Internally, the O2 Sensor circuit may be shorted to voltage or ground due to poor wiring.
  • The exhaust system ground strap may be corroded.
  • The cables from the PCM to the sensor heater circuit are defective.

Possible solutions of the DTC code P0056

When troubleshooting the diagnostic code P0056 OBDII, take into account the following:

  • Check the cable system, if there are poor or badly adjusted connections, you should repair or replace them if necessary.
  • Disconnect the Oxygen Sensor related to this code and use a digital voltmeter in ohm reading. Test the circuit resistance and use a wiring diagram as a reference. If the resistance is excessive, it is due to an opening in the circuit. You must change the O2 Sensor.
  • Verify good grounding and correct resistance at the Oxygen Sensor
  • Test the power cable at the connector using the voltmeter set to volts DC. Connect the positive cable to the power cable and the negative cable to a good ground source. If there is no electricity at the connector on the initial startup, i.e., the engine is cold, there is a problem in the power supply circuit from the PCM to the O2 Sensor. Make the necessary repairs.

Codes related to P0056

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