What is OBD-II Code P2B15 – Cylinder 3 Injection Pulse Offset Exceeded Learning Limit

What is OBD-II Code P2B15 – Cylinder 3 Injection Pulse Offset Exceeded Learning Limit

When you see the check engine light on your dashboard, it can be hard not to panic. After all, it could be anything from a minor issue to a major problem that could put your car out of commission. Fortunately, OBD codes can give you a clue about what’s wrong with your vehicle. One code that you might see is P2B15, which refers to a problem with the cylinder 3 injection pulse offset learning limit. In this article, we’ll explain what that means and how to fix it.

What is OBD-II Code P2B15?

To understand what OBD-II Code P2B15 means, you first need to know a bit about how fuel injection systems work. In modern cars, the engine’s fuel is sprayed directly into the combustion chamber through a fuel injector. The timing and duration of the fuel spray is critical to the engine’s performance: too little fuel and the engine won’t run properly, too much and you’ll waste gas and put extra wear on the engine.

In order to optimize fuel injection timing, your car’s computer (also known as the Powertrain Control Module, or PCM) relies on a system of sensors and feedback loops to adjust the fuel injection pulse width (the amount of time that the injector is open). The PCM has a learning function that allows it to adjust the pulse width over time to improve engine performance and fuel efficiency.

OBD-II Code P2B15 indicates that the PCM has determined that the offset between the commanded fuel injection pulse width and the actual pulse width delivered by the fuel injector for cylinder 3 has exceeded the learning limit. In other words, the PCM has tried to adjust the pulse width for cylinder 3, but has reached a point where the injector is not responding correctly to the adjustments.

What causes OBD-II Code P2B15?

Several factors can contribute to OBD-II Code P2B15:

– Faulty fuel injector: Over time, fuel injectors can become clogged with debris or wear out, causing them to malfunction. When a fuel injector fails, it may not spray the correct amount of fuel, which can result in poor engine performance and reduced fuel efficiency.

– Electrical problem: An issue with the wiring or connectors that supply power to the fuel injector can cause it to malfunction. For example, a broken wire or corroded connector could cause the injector to receive too little or too much voltage, which could affect the timing of the fuel spray.

– PCM problem: In some cases, the PCM itself can malfunction, which could cause it to be unable to learn the correct fuel injection pulse width for cylinder 3 or to calculate the correct pulse width based on sensor data. This is less common than the other causes of P2B15, but it’s still possible.

How to diagnose and fix OBD-II Code P2B15

Because OBD-II Code P2B15 can have several different causes, diagnosing and fixing the issue can be a bit tricky. Here are some steps to follow:

Step 1: Check the fuel injector. The first thing to do is to inspect the fuel injector for cylinder 3 to see if it’s malfunctioning. You can do this by using a multimeter to measure the resistance of the injector, or by using a fuel pressure gauge to check the fuel flow. If the injector is faulty, it will need to be replaced.

Step 2: Check the wiring and connectors. Next, you’ll want to check the wiring and connectors that supply power to the fuel injector. Look for broken wires, damaged connectors, or corrosion. If you find any issues, repair or replace the affected components.

Step 3: Check the PCM. If the fuel injector and wiring are both functioning correctly, the problem may be with the PCM itself. You can check this by using an OBD-II scan tool to read the PCM’s error codes and datastream. Look for any other codes or data that suggest a problem with the PCM. If you suspect that the PCM is malfunctioning, you may need to take your car to a professional mechanic to have it repaired or replaced.

Step 4: Reset the PCM. Once you’ve fixed any issues with the fuel injector, wiring, or PCM, you’ll need to reset the PCM to clear the error code. You can do this by disconnecting the battery for 15-30 minutes, or by using an OBD-II scan tool to clear the code directly from the PCM.

Frequently Asked Questions (FAQs)

Q: What are OBD-II codes?
A: OBD-II (On-Board Diagnostics version 2) codes are a standardized system that car manufacturers use to report problems with various systems in your vehicle. These codes are useful for troubleshooting and diagnosing issues with your car.

Q: What does the check engine light mean?
A: The check engine light is a warning light that appears on your dashboard when the PCM has detected an issue with one or more of your car’s systems.

Q: Can I still drive my car with the check engine light on?
A: It depends on the issue causing the check engine light to come on. In some cases, it may be safe to drive your car for a short period of time, but in others, you may risk damaging your engine if you continue to drive with the check engine light on.

Q: Can I use an OBD-II scan tool to diagnose and fix issues with my car?
A: While an OBD-II scan tool can be useful for diagnosing issues with your car, in most cases, it won’t be enough to fix the problem. You’ll need to use other diagnostic tools, such as a multimeter or fuel pressure gauge, to diagnose and fix the issue.

Q: What should I do if I can’t diagnose or fix an issue with my car on my own?
A: If you’re unable to diagnose or fix an issue with your car on your own, it’s best to take it to a professional mechanic. They’ll have the tools and expertise needed to solve the problem.


OBD-II Code P2B15 is a specific code that indicates a problem with the cylinder 3 injection pulse offset learning limit. While this code can be caused by several different issues, diagnosing and fixing the problem often requires a combination of tools and expertise. If you’re unsure how to diagnose or fix the issue on your own, it’s best to take your car to a professional mechanic. By taking care of issues like this quickly, you can help ensure that your car runs smoothly and efficiently for years to come.

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