How to fix P0159 O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)

As a car owner, you might encounter various problems with your vehicle, and one of the most common issues is a faulty oxygen sensor.

One of the codes that might flash on your dashboard is P0159, signaling an O2 sensor circuit high voltage on bank 2 sensor 2.

This code indicates that the secondary O2 sensor on the second bank of your engine is reading a voltage that is higher than the expected range. In this article, we will discuss this problem in detail, including its causes, symptoms, and potential solutions.

What is an O2 sensor?

Before diving into the specifics of P0159 code, let’s first understand the role of an O2 sensor in your vehicle. The O2 sensor is an essential component of your car’s emissions system that measures the amount of oxygen in the exhaust system.

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It sends this information to the engine control module (ECM), which uses it to adjust the air-fuel ratio for optimal combustion.

The oxygen sensor is located in the exhaust manifold or near it, and it can be either a primary or secondary sensor.

What causes P0159 code?

Now that you know what an O2 sensor is let’s discuss the causes of P0159 code. The first and most common cause is a faulty oxygen sensor.

The sensor may be damaged, or the wiring harness may be faulty, leading to a high voltage reading.

Another possible cause is a vacuum leak in the intake manifold, which can cause an incorrect air-fuel ratio and trigger the code.

Additionally, a clogged fuel filter or a weak fuel pump can cause insufficient fuel delivery, leading to a high voltage reading.

What are the symptoms of P0159 code?

If your vehicle triggers the P0159 code, you may notice several symptoms. One of the first signs is reduced engine performance and fuel economy. You may also experience rough idle, stalling, or hesitation during acceleration. Moreover, you might notice a foul smell or smoke coming from the exhaust system, indicating incomplete combustion.

How to diagnose P0159 code?

Diagnosing P0159 code can be done in several ways, depending on the severity of the problem and the type of vehicle.

One of the most common methods is to use a scan tool to read the code and check for any related trouble codes.

Afterward, you can test the O2 sensor using a digital multimeter to determine its resistance and voltage. If the sensor is faulty, you will need to replace it; if not, you can move on to check the wiring harness and other components.

How to fix P0159 code?

Fixing P0159 code depends on the root cause of the problem. If the issue is a faulty oxygen sensor, you will need to replace it with a new one.

It’s essential to use a high-quality sensor from a reputable brand to ensure accurate readings and long-term durability.

If the issue is a vacuum leak, you will need to locate and repair it by replacing the gasket or seal. In case of a clogged fuel filter or weak fuel pump, you will need to replace them with new ones.


P0159 code is a common problem that car owners face due to a faulty oxygen sensor on bank 2 sensor 2. It can cause reduced engine performance, fuel economy, and other symptoms.

Diagnosing and fixing the problem requires careful evaluation of the sensor, wiring harness, and other components.

If you encounter this code, don’t ignore it; instead, take your car to a professional mechanic and get it fixed as soon as possible.


  1. Can I drive my car with P0159 code?

Driving your car with P0159 code is not recommended as it can cause reduced engine performance and fuel economy, leading to potential damage to your vehicle.

  1. How much does it cost to fix P0159 code?

The cost of fixing P0159 code depends on the root cause of the problem. It can range from $50 to $500, depending on the extent of the damage and the cost of the replacement parts.

  1. Can I replace the oxygen sensor myself?

Replacing the oxygen sensor requires some technical knowledge and tools, and it’s recommended to be done by a professional mechanic. However, if you have experience in auto repair, you can do it yourself, but it’s essential to follow the manufacturer’s instructions and safety guidelines.

  1. How often should I replace my O2 sensor?

The lifespan of an O2 sensor varies depending on the manufacturer and the vehicle’s usage. Typically, it lasts between 50,000 to 100,000 miles, and it’s recommended to replace it every 60,000 miles as part of your car’s maintenance.

  1. What happens if I ignore P0159 code?

Ignoring P0159 code can cause severe damage to your vehicle’s engine, leading to costly repairs. It’s essential to diagnose and fix the problem as soon as possible to prevent any further damage.