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P0164 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.


DTC codes are alphanumeric designations used by the vehicle’s On-Board Diagnostic (OBD) system to pinpoint specific issues within various components. P0164 corresponds to the O2 sensor circuit on Bank 2 Sensor 3, also known as an upstream O2, and is a DTC. When exhaust gases are passed through the catalytic converter, this sensor has a key role to play in determining their oxygen content.


A problem with the voltage of the downstream O2 sensor on Bank 2 is indicated by the P0164 code. In particular, it has been detected that the voltage output is not within the expected range. There are a variety of factors that may be contributing to this difference between the readings provided by the sensor.


  • Faulty Oxygen Sensor: One of the main root causes of the P0164 error code is a defective downstream O2 sensor. Voltage measurements can become erroneous as a result of dirty or worn-out sensors.
  • Wire or Connector Problems: The downstream O2 sensor’s wire and connections that are damaged or corroded might obstruct the signal’s transfer and impact the voltage output.
  • Leaks in the Exhaust System: Any leaks in the exhaust system close to the downstream O2 sensor may bring erroneous air into the system and affect the voltage readings of the sensor.


  • Check Engine Light Illumination: The Check Engine Light illumination on the dashboard of the car is the P0164 code’s most obvious symptom.
  • Worse Fuel Efficiency: Inadequate fuel mixture regulation caused by a faulty downstream O2 sensor with low voltage output might result in worse fuel economy.
  • Problems with engine performance: Due to inaccurate sensor readings, your engine may have less power, a rough idle, or trouble starting.


The P0164 code must be diagnosed using a methodical process:

  • OBD-II Scanner: A skilled mechanic will access the vehicle’s Engine Control Module (ECM) with an OBD-II scanner to extract the recorded DTCs.
  • Visual Inspection: The downstream O2 sensor, its cabling, and its connections will be visually inspected by the technician for any obvious flaws or damage.
  • Sensor Testing: Under varied exhaust circumstances, the voltage output of the downstream O2 sensor may be tested using specialized diagnostic equipment.
  • Cross-checking: The technician can validate the problem by comparing the upstream O2 sensor readings and the actual sensor voltage readings to the predicted values.

Common mistakes

  • Without confirming the root cause, an O2 sensor replacement may be necessary since another factor, such as electrical problems or exhaust system leakages, is likely to have contributed to a lower voltage output. 
  • Failure to check for the relevant problem codes could help with further understanding of this issue.

How serious is this?

Although the P0164 code cannot cause immediate and severe drivability problems, it should not be ignored. If a downstream O2 sensor is not functioning properly with low voltage outputs, its failure can cause an increase in emissions and a loss of fuel efficiency, which may become more serious problems over time if they are not addressed.

What repairs can fix the code?

repair manuals

  • O2 Sensor Replacement: If the downstream O2 sensor is identified as defective or gives low voltage readings, the problem can be fixed by replacing it with a brand-new, high-quality sensor.
  • Repairing wire or connections: Correct signal transmission and voltage readings can be obtained by addressing any corroded or damaged wire and connections connected to the sensor.
  • Repairing Exhaust System Leaks: The voltage readings of the downstream O2 sensor can be enhanced by fixing any leaks in the exhaust system close by.

Related codes

  • P0163: O2 Sensor Circuit Slow Response (Bank 2, Sensor 3)
  • P0150: O2 Sensor Circuit (Bank 2, Sensor 1)


The downstream O2 sensor on Bank 2 is related to the P0164 DTC code, which denotes low voltage output. Vehicle owners and mechanics can respond appropriately if they are aware of the meaning, causes, symptoms, and potential fixes for this code. Maintaining optimal engine performance, fuel efficiency, and pollution control will be made easier with prompt diagnosis and repair of the problem. 

It is vital to seek help from a qualified technician for an efficient solution to problems, which will ensure that your vehicle operates properly and effectively if you come across the P0164 code or suspect an O2 sensor problem.

P0164 Code – What Does It Mean & How To Fix It