The P0302 engine code can cause serious drivability issues, so you’ll need to address the underlying problem (or problems) right away.
If the check engine light has popped up on your vehicle and the OBD-II scanner reads a P0302 code, here’s everything you’ll need to know to help you address it.
What Does the P0302 Code Mean?
Diagnostic trouble code (DTC) P0302 stands for “Cylinder 2 Misfire Detected.” The code indicates that your car’s primary computer, also known as the powertrain control module (PCM), has detected a misfire on cylinder 2.
A misfire is either incomplete combustion (or the absence of combustion) in one of the engine’s cylinders. Combustion, which is a small explosion, takes place when a pressurized air-fuel mixture is ignited inside the engine. The combustion event sends the piston moving downward, which, in turn, rotates the crankshaft to create the rotational force needed to put your car in motion.
Code P0302 is part of a series of misfire DTCs that range from P0300 to P0012. Each code between P0301 and P0312 indicates a misfire on a particular cylinder. For example, code P0301 indicates a misfire on cylinder one and code P0312 indicates a misfire on cylinder 12 (if your car has a 12-cylinder engine). Code P0300 is a bit different because it implies a “random misfire” rather than a misfire on a particular cylinder.
When there is a misfire, the crankshaft speed becomes slower than usual. The PCM monitors the crankshaft speed for each cylinder. The device will set a P0302 code when it detects a misfire.
What are the Possible Causes of the P0302 Code?
There are many factors that can cause a cylinder 2 misfire—the most common of which are the following:
- Fuel delivery issues (e.g., a faulty fuel injector or damaged injector circuit)
- Ignition system problems (e.g., a failed coil pack or worn spark plug)
- Engine mechanical issues (e.g., a sticking valve or weak piston rings)
It’s worth noting that, if other misfire codes accompany a P0302, there will likely be more than one potential cause. Code P0302 by itself is a good indicator that the problem is with cylinder 2 only.
On the other hand, multiple misfire codes can indicate an issue, such as a vacuum leak or low fuel pressure, that affects various cylinders.
To make diagnosis even more difficult, a cylinder 2 misfire can confuse the PCM and cause P0300 and other misfire codes to set.
What are the Common Symptoms of the P0302 Code?
As previously mentioned, a P0302 may be accompanied by other codes, in which case you may observe symptoms that may not be mentioned here. If your PCM is only storing a P0302, however, these are some common signs that your vehicle may exhibit:
- Check engine indicator light is on or flashing
- Running rough
- Difficulty starting the engine
- Foul odor coming from the exhaust
- Decrease in power
- Excessive fuel consumption
How to Diagnose the P0302 Code
There are many possible causes that can trigger code P0302, so you will need a detailed guide on how to diagnose the code properly.
Below are a couple of video references you can use to help you understand and properly execute the diagnostic process:
How to Fix the P0302 Code
To be honest, there are no simple, umbrella solutions to most—if not all—OBD-II trouble codes. If you aren’t well-versed with automotive repair, it may be best to leave it to a professional. However, if you are confident in your DIY skills, the first step is to properly diagnose the underlying issue. Once you’ve determined what’s causing the P0302 code to set, you can then figure out the appropriate fix with the help of online auto repair resources and guides.
You could also get an ALLDATA single-vehicle subscription, which will definitely be useful for any future repairs your vehicle may need.
Lastly, different carmakers and vehicles may have their own specific repair instructions. What works with one car might not work for another, so make sure to consult your owner’s manual before attempting to fix a code P0302.