What is OBD-II Code P2A56 – Alternative Fuel Vaporizer B Outlet Temperature Sensor Range/Performance

What is OBD-II Code P2A56 – Alternative Fuel Vaporizer B Outlet Temperature Sensor Range/Performance

If you’ve ever had a check engine light come on, you know it can be concerning. One of the codes you may see is P2A56. This code is specific to alternative fuel vehicles, and it relates to the temperature sensor in the fuel vaporizer system. In this article, we’ll explain what that means and how to address the issue.

What is an alternative fuel vaporizer system?

Alternative fuel vaporizer systems are part of the emissions control systems found in some vehicles. These systems allow vehicles to run on non-conventional fuels such as propane or natural gas. The fuel is vaporized and then fed into the engine.

What does the P2A56 code mean?

The P2A56 code is specific to the alternative fuel vaporizer system. It relates to the temperature sensor in the “B” outlet. This sensor is responsible for measuring the temperature of the fuel vapor as it leaves the vaporizer before entering the engine.

When the sensor’s readings fall outside of the expected range for the vehicle, the check engine light will come on and the P2A56 code will be stored in the vehicle’s onboard diagnostic (OBD-II) system. The “range/performance” part of the code indicates that the sensor’s readings are either outside of the expected range or that the sensor is not performing as it should.

What are the symptoms of the P2A56 code?

In some cases, the only symptom may be the check engine light coming on. However, if the sensor is reading incorrectly, it can cause a few other issues. One symptom may be a decrease in performance or fuel economy. This is because the engine’s computer relies on the sensor readings to adjust the fuel delivery to the engine. If the readings are incorrect, the engine may not be receiving the right amount of fuel.

Additionally, if the sensor is reading too high, it may cause the engine to run too lean. This can cause the vehicle to stall or run roughly.

How is the P2A56 code diagnosed?

The first step in diagnosing the P2A56 code is to use an OBD-II scanner to read the code. This can help to determine if there are any additional codes stored in the system that may provide more information about the issue.

Once the code has been read, a technician will need to inspect the fuel vaporizer system and the temperature sensor. They may need to use a multimeter to test the sensor’s readings, and they may also need to check the wiring and connections for any issues.

How is the P2A56 code repaired?

The repair for the P2A56 code will depend on the cause of the issue. In some cases, simply cleaning or replacing the sensor may solve the problem. In other cases, there may be wiring or connection issues that need to be addressed.

If the sensor itself is not the issue, the technician may need to inspect the fuel system for any leaks or other issues that may be affecting the temperature readings.

Frequently Asked Questions

1. What happens if I don’t address the P2A56 code?

If the P2A56 code is ignored, it can cause other issues with the vehicle’s performance and fuel economy. Additionally, it could cause the vehicle to fail an emissions test.

2. Can I still drive my vehicle with the P2A56 code?

In most cases, it is safe to drive the vehicle with the P2A56 code, but it’s a good idea to have it addressed as soon as possible.

3. Can I diagnose and repair the P2A56 code myself?

If you have the necessary tools and experience, you may be able to diagnose and repair the P2A56 code yourself. However, it’s important to remember that working on your vehicle’s emissions control systems can be dangerous and may require specialized equipment.

4. How common is the P2A56 code?

The P2A56 code is not one of the more common codes, as it is specific to alternative fuel vehicles.

5. How can I prevent the P2A56 code from coming back?

The best way to prevent the P2A56 code from coming back is to address the underlying issue. Regular maintenance and inspections of the vehicle’s emissions control system can also help to prevent issues from occurring.


When the check engine light comes on, it can be worrisome. However, with the right information and approach, addressing the P2A56 code can be a relatively simple process. If you have an alternative fuel vehicle and are experiencing issues with the fuel vaporizer system, it’s important to address them promptly to avoid further issues.

Resources for Further Reading

1. OBD-II Trouble Codes
2. Understanding Alternative Fuels
3. Vehicle Emissions Control Systems: Theory, Design and Performance
4. The Complete Guide to Vehicle Maintenance and Repair
5. Emissions Testing Procedures and Requirements by State

Scroll to Top