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P0333 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P0333 is a Diagnostic Trouble Code (DTC) within the On-Board Diagnostics II (OBD-II) system used in modern vehicles. The problem with the Knock Sensor 2 Circuit High Input Bank 2 is specifically addressed in this code.


The knock sensor in Bank 2 sent a high-voltage signal to the engine control module (ECM), which was recognized by the P0333 code. Engine banging or pinging, which may signify aberrant combustion, is picked up by the knock sensor. A knock situation that may not truly exist is being detected by the ECM when it gets a high-voltage signal from the knock sensor. This might affect engine performance.


The P0333 error code may appear for several reasons, including:

  • Faulty Knock Sensor: The ECM may receive inaccurate voltage signals from a knock sensor that is broken or not working properly.
  • Wiring Issues: Damaged or corroded wiring in the knock sensor circuit can lead to high voltage readings
  • Loose or Corroded Connectors: Loose or corroded electrical connectors in the knock sensor circuit can disrupt the signal.
  • Engine Mechanical Problems: Problems with engine components, such as excessive carbon buildup or incorrect spark plug gaps, can cause false knock sensor readings.
  • Faulty ECM: A faulty engine control module can occasionally result in false P0333 codes.


  • The following symptoms may be present when a P0333 code is present:
  • Decreased engine power and performance.
  • Illumination of the dashboard’s Check Engine Light (CEL).
  • Possible engine pinging or banging noises
  • Fuel economy dropped.


To diagnose and confirm a P0333 code, a mechanic or technician will typically perform the following steps:

  • Use an OBD-II scanner to retrieve the trouble codes and freeze frame data.
  • Inspect the knock sensor and its wiring for physical damage or corrosion.
  • Check for loose or disconnected electrical connectors in the knock sensor circuit.
  • Test the knock sensor’s resistance and voltage output
  • Inspect the engine for mechanical issues that could cause false knock sensor readings.
  • If necessary, test the ECM for faults using specialized diagnostic equipment.

Common mistakes

Common mistakes when dealing with a P0333 code include:

  • Replacing the knock sensor without checking for wiring or connector issues.
  • Ignoring other potential causes of engine knocking, such as carbon buildup or spark plug problems.
  • Failing to clear the code and retest the vehicle after making repairs.

How serious is this?

It is not possible to cause instant engine damage with the P0333 code, so do not ignore it. If knocking or pinging occurs, failure of the code could lead to decreased engine performance, lower fuel economy, and possible longer-term engine damage. This issue should be dealt with immediately.

What repairs can fix the codeS?

repair manuals

Repairs to address a P0333 code may include:

  • Replacing the Knock Sensor: If the knock sensor is found to be faulty, it should be replaced with a new one.
  • Repairing or Replacing Wiring: If damaged or corroded wiring is identified, it should be repaired or replaced.
  • Addressing Engine Mechanical Issues: If engine mechanical problems are causing false knock sensor readings, they should be resolved.
  • Testing and Potentially Replacing the ECM: If all other possibilities are ruled out, testing and potentially replacing the engine control module may be necessary.

Related codes

Codes related to P0333 may include:

  • P0323: Knock Sensor Circuit, High Input
  • P0324: Knock Control System Error (Circuit Range/Performance)


The P0333 DTC code addresses a problem with the Knock Sensor 2 Circuit, High Input Bank 2). It signifies that the engine control module is receiving an excessively high voltage signal from the knock sensor, which can lead to engine performance issues. In order not to cause additional damage and regain vehicle performance, prompt diagnosis and repair are essential. Failure to deal with this code could result in decreased fuel efficiency and engine damage, so it is recommended that the problem be fixed as soon as possible.

P0333 Code – What Does It Mean & How To Fix It