P0164 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 3)

One of the most common causes of a check engine light (CEL) is a faulty oxygen sensor.

The oxygen sensor, or O2 sensor, plays a vital role in ensuring that the engine runs smoothly and efficiently.

It measures the amount of oxygen in the exhaust stream and relays this information to the engine control module (ECM), which adjusts the air/fuel mixture accordingly.

When the O2 sensor detects that there is too little oxygen in the exhaust stream, it sends a signal to the ECM to increase the amount of fuel injected into the engine.

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Conversely, when there is too much oxygen in the exhaust stream, the O2 sensor signals the ECM to decrease the amount of fuel.

This continuous feedback loop helps to maintain an optimal air/fuel ratio, which maximizes engine performance and fuel economy.

However, if the O2 sensor malfunctions, it can cause the engine to run poorly and consume more fuel than necessary. This is why it is essential to diagnose and repair any O2 sensor-related issues as soon as possible to avoid further damage to the engine and reduce fuel consumption. In this article, we will discuss the P0164 O2 sensor circuit low voltage (bank 2 sensor 3) code, its causes, symptoms, and how to diagnose and fix it.


The P0164 code indicates that the O2 sensor circuit on bank 2 sensor 3 has a low voltage condition. This code can be triggered by several factors, including:

  1. A faulty O2 sensor: The most common cause of the P0164 code is a malfunctioning O2 sensor. The sensor may have failed due to age, contamination, or damage.
  2. Worn or damaged wiring: The wiring that connects the O2 sensor to the ECM may be worn or damaged, causing a short circuit or an open circuit.
  3. Loose or corroded connections: The connections between the O2 sensor and the wiring harness or the ECM may be loose or corroded, causing a poor electrical connection.
  4. Failed ECM: In rare cases, the ECM may have failed, causing the P0164 code to be triggered.


The P0164 code can cause several symptoms, including:

  1. A decrease in engine performance: The engine may run poorly, with reduced power and acceleration.
  2. Poor fuel economy: The engine may consume more fuel than usual, leading to reduced gas mileage.
  3. Rough idle: The engine may idle roughly, with uneven RPMs and vibrations.
  4. Check engine light: The CEL will illuminate, indicating that there is a problem with the O2 sensor circuit.


To diagnose the P0164 code, you will need an OBD-II scanner, a multimeter, and a wiring diagram for your vehicle. Here are the steps to follow:

Step 1: Connect the OBD-II scanner to the diagnostic port under the dashboard and retrieve the trouble codes.

Step 2: Check the freeze frame data to see when and under what conditions the P0164 code was triggered.

Step 3: Inspect the O2 sensor and its wiring for damage or wear. Use a multimeter to test the circuit continuity.

Step 4: Check the connections between the O2 sensor and the wiring harness or the ECM for corrosion or looseness.

Step 5: If there is no visible damage to the wiring or the O2 sensor, test the signal voltage and ground circuit of the O2 sensor using a multimeter.

Step 6: If all the above tests fail, replace the O2 sensor or the ECM.

Fixing the P0164 Code:

The following are the steps to fix the P0164 code:

  1. Replace the O2 sensor: If the O2 sensor is faulty, you will need to replace it with a new one. Make sure you get the correct sensor for your vehicle’s make and model.
  2. Repair the wiring: If the wiring is worn or damaged, you will need to repair or replace it. Make sure you use the correct gauge wiring and connectors.
  3. Clean the connections: If the connections are loose or corroded, clean them with a wire brush and apply dielectric grease to prevent further corrosion.
  4. Replace the ECM: If the ECM has failed, you will need to replace it with a new one. This is a rare occurrence and should only be done after all other possible causes have been ruled out.


The P0164 O2 sensor circuit low voltage (bank 2 sensor 3) code is a common issue that can cause several symptoms, including poor engine performance and fuel economy. The causes of this code include a faulty O2 sensor, worn or damaged wiring, loose or corroded connections, or a failed ECM. To diagnose and fix this code, you will need to use an OBD-II scanner, a multimeter, and a wiring diagram for your vehicle. Always ensure that you get the correct replacement parts and follow the manufacturer’s instructions when fixing the code.


  1. Can the P0164 code cause any other codes to be triggered?

    A: Yes, the P0164 code can cause other O2 sensor-related codes to be triggered.

  2. How often should I replace my O2 sensor?

    A: O2 sensors typically last between 50,000 and 100,000 miles. However, this can vary depending on your driving conditions and vehicle make and model.

  3. Can a bad O2 sensor cause my engine to fail emissions testing?

    A: Yes, a malfunctioning O2 sensor can cause your vehicle to fail emissions testing.

  4. Can I drive my vehicle with the P0164 code?

    A: It is not recommended to drive your vehicle with the P0164 code, as it can cause further damage to the engine and reduce fuel economy.

  5. Can I fix the P0164 code myself?

    A: If you have the necessary tools and knowledge, you can fix the P0164 code yourself. However, if you are unsure, it is best to take your vehicle to a qualified mechanic.