What is OBD-II Code P2AF0 – Intake Air O2 Sensor Negative Current Control Circuit Low Bank 2

What is OBD-II Code P2AF0 – Intake Air O2 Sensor Negative Current Control Circuit Low Bank 2

As a mechanic, one of the most common problems I encounter is a Check Engine light accompanied by an OBD-II code. While these codes can seem intimidating for the average person, they actually provide important information about what is going on under the hood of your vehicle. In this article, I’ll explain what OBD-II Code P2AF0 means, how to diagnose the issue, and how to fix it.

What is OBD-II?
First, let’s start with the basics. OBD-II stands for On-Board Diagnostics, and it is a system that has been installed on all vehicles in the United States since 1996. This system monitors the performance of your car’s engine and emissions systems and alerts you to any issues that arise.

When your Check Engine light comes on, it means that there is a problem with one of your vehicle’s systems. An OBD-II scanner can be used to diagnose this problem, and it will provide you with a specific code that describes the issue. There are hundreds of different OBD-II codes, and each one tells you something different about your car.

What is OBD-II Code P2AF0?
OBD-II Code P2AF0 is an issue with the intake air O2 sensor negative current control circuit on bank 2 of the engine. This sensor is responsible for monitoring the amount of oxygen in the intake air of the engine, which is used to calculate the air/fuel ratio. The negative current control circuit is what controls the amount of current that flows through the sensor.

If this circuit is detecting a low voltage or a loss of signal, it will trigger the Check Engine light and set the P2AF0 code.

What are the Symptoms of OBD-II Code P2AF0?
There aren’t any specific symptoms associated with this code, as it can be triggered by a variety of issues. However, you may notice that your engine is running poorly, or you may have noticed a decrease in fuel mileage.

How to Diagnose OBD-II Code P2AF0?
The first step in diagnosing this code is to use an OBD-II scanner to read the code and access freeze frame data. This data can give you more information about when the code was triggered and under what conditions.

Next, you’ll need to visually inspect the wiring and connectors for the intake air O2 sensor. Look for any signs of damage or corrosion, and check for proper connections. If the wiring and connectors look good, you can use a multimeter to test the voltage on the sensor and make sure it is within specification.

If everything checks out with the wiring and connectors, the next step is to test the sensor itself. This is typically done by disconnecting the sensor and using a volt-ohm meter to test the resistance of the sensor.

How to Fix OBD-II Code P2AF0?
If you’ve determined that the issue is with the intake air O2 sensor, the only fix is to replace the sensor. This is a relatively simple repair, and the cost can vary depending on your vehicle make and model.

It’s important to note that if the sensor is not the issue, it may be necessary to further diagnose the negative current control circuit. This can involve more complex repairs, such as replacing the ECM or repairing damaged wiring.


1. Can I still drive my car with OBD-II Code P2AF0?
While you can technically still drive your car with this code, it is not recommended. The code indicates a problem with your engine, and continuing to drive can cause more damage and potentially lead to a more expensive repair.

2. How long does it take to diagnose OBD-II Code P2AF0?
The time it takes to diagnose this code can vary, depending on the specific issue. However, it is typically a relatively quick diagnosis, and most mechanics should be able to give you an estimate of how long it will take.

3. Can I clear OBD-II Code P2AF0 without fixing the issue?
You can clear the code with an OBD-II scanner, but this will not fix the underlying problem. The code will likely return until the issue is properly diagnosed and repaired.

4. What causes OBD-II Code P2AF0?
There are several potential causes of this code, including a faulty intake air O2 sensor, damaged wiring, or a failed ECM. Proper diagnosis is necessary to determine the specific cause.

5. How can I prevent OBD-II Code P2AF0 from happening again?
Regular maintenance and inspections can help prevent this code from occurring. Make sure to have your engine and emissions systems checked regularly by a qualified mechanic.

In conclusion, OBD-II Code P2AF0 is a common issue that can be diagnosed and fixed relatively easily. If you encounter this code, take your vehicle to a trusted mechanic who can properly diagnose and repair the issue. Remember, regular maintenance and inspections can help prevent Check Engine lights and other issues from occurring in the first place.

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