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P0168 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.


A problem with the O2 sensor circuit in Bank 2 Sensor 3 of the vehicle is indicated by the P0168 DTC code. It is important to keep in mind that, for certain vehicles and models, such a specific code may not apply. It is essential to consult the documents of the vehicle or seek advice from an auto expert in order to provide a correct interpretation.


The O2 sensor in Bank 2 Sensor 3 is providing a high-voltage signal when the P0168 code is activated. The O2 sensor’s data is used by the Engine Control Module (ECM) or Powertrain Control Module (PCM) to modify the air-fuel ratio. High voltage output sensors that aren’t working properly might have a detrimental effect on emissions and engine performance.


The P0168 DTC code may appear as a result of several factors:

  • Faulty O2 Sensor: The O2 sensor itself may be faulty, generating high voltage signals and triggering the code.
  • Wire Issues: Corroded or damaged wire inside the O2 sensor circuit might prevent signal transmission, resulting in readings of excessive voltage.
  • Exhaust System Leaks: Exhaust system leaks can contaminate the O2 sensor, resulting in erroneous voltage indications from the sensor.
  • ECM/PCM Issues: The O2 sensor may give false readings if there are issues with the vehicle’s Engine Control Module or Powertrain Control Module.


The following symptoms may appear when the P0168 DTC code is present:

  • Illuminated Check Engine Light: The most noticeable symptom is the illumination of the check engine light on the vehicle’s dashboard.
  • Reduced Fuel efficiency: An O2 sensor issue might make the engine perform less effectively, which lowers fuel efficiency.
  • Engine Performance Issues: The vehicle may exhibit rough idling, hesitation, or a lack of power during acceleration.
  • Emissions Issues: Due to higher emissions brought on by an incorrect air-fuel combination, the vehicle may fail an emissions test.


A competent mechanic must use a methodical methodology to accurately diagnose the P0168 DTC code. The diagnostic procedure might entail:

  • OBD-II Scanner: Using an OBD-II scanner, the mechanic can retrieve the trouble code and other relevant data from the vehicle’s onboard computer.
  • Visual Inspection: The O2 sensor and its wiring must be thoroughly inspected visually for any obvious deterioration or damage.
  • Testing the O2 Sensor: The mechanic may do experiments to check the voltage output and reaction time of the O2 sensor to modifications in the exhaust gas composition.
  • Resolving associated Problems: Prior to concentrating on the O2 sensor check, it is essential to resolve any exhaust leaks or other associated issues.

Common mistakes

It is crucial to prevent frequent errors while working with the P0168 code, such as:

  • Ignoring Other Codes: P0168 could be accompanied by other relevant codes, and ignoring them could result in missing important problems.
  • Incorrect Component Replacement: An incorrect diagnosis may result in the replacement of an O2 sensor that is still operational rather than addressing wiring or ECM/PCM problems.
  • Ignoring Maintenance: The performance of the O2 sensor and other engine parts might be affected by routine maintenance, such as cleaning or changing air filters.

How serious is this?

Different factors, including the make and model of the vehicles, operating conditions, and extent of the problem, affect the seriousness of P0168 DTC codes. As long as the vehicle is operating with a code at present, failing to keep that code in place could lead to reduced fuel efficiency and possible catalytic converter damage. In order to avoid further complications, it is advisable to resolve the problem as soon as possible.

What repairs can fix the code?

repair manuals

The P0168 DTC code can be fixed using the following fixes, depending on the diagnosis:

  • Changing the O2 Sensor: If the O2 sensor is broken, replacing it with a fresh, working one should fix the problem.
  • Repairing wire: The O2 sensor circuit’s broken or corroded wire can be fixed to enable correct signal transmission.
  • Sealing Exhaust Leaks: Sealing leaks in the exhaust system will stop the O2 sensor from being further contaminated.
  • ECM/PCM Reprogramming or Replacement: If the Engine Control Module or Powertrain Control Module is at fault, reprogramming or replacing it may be necessary.

Related codes

Other related DTC codes include P0166 (O2 Sensor Circuit No Activity Detected Bank 2 Sensor 3) and P0167 (O2 Sensor Circuit Low Voltage Bank 2 Sensor 3). These codes may offer additional insights into the underlying issue.


Potential issues with the O2 sensor in Bank 2 Sensor 3 can be detected by a P0168 DTC code. In order to maintain optimum engine performance, fuel economy and emissions compliance, timely diagnosis and correct repairs are essential. It is recommended to seek professional automotive advice if this code has been detected so that the problem can be identified and resolved in a satisfactory manner, which will make it easy for you to drive safely.

P0168 Code – What Does It Mean & How To Fix It