Other P030 errors point to other cylinders not working correctly.
For example, the P0302 code is spark plug-2 misfire, and P0303 would be spark plug-3.
P0301 Error Code Causes
- Bad Spark Plug
- Spark Plug Wires
- Bad Coil
- Fuel Injector
P0301 OBDII Error Code Cause and Fixes
- Check Spark Plug Wires, Coil Pack, and Injector
- Check the Spark Plug Wire
- Check the Spark Plug
- Test the Fuel Injector
- Swap Parts with Working Cylinder.
Often the problem won’t be visible, but it is a good place to start; plus, it helps to know their location.
Many mechanics will swap the spark plug with another one to see if the problem follows.
If the plug wires are swapped, be sure not to mix up the firing order, and take pictures if necessary.
Sometimes the spark plug will be old and need to be replaced.
Often, something else is causing the plug not to get power for a spark and will have a lot of build-up.
A bad Fuel Injector can also be a problem.
Again an easy way to check is to swap it out with a known good one and see if the problem follows
A low-cost way to narrow down the problem is to swap out parts one at a time with a working cylinder.
For example, if cylinder two is working, swap the coil pack with one or three and see if the problem follows.
If the P0301 clears but a code P0302 comes up after the swap, you will know the coil pack is bad.Summary
Fixing a P0301 is usually easy enough and falls in the backyard mechanic DIY category.
Of course, call a professional if in doubt.
The make and model of a vehicle will make a difference as some will be easier to work on than others.
Some cars and trucks will have parts that can be easily swapped, while others will be more difficult.
While it is best to find and replace the problem part if all the parts are old and the vehicle hard to work on, sometimes it is best to simply replace all new parts.