How To Fix P0305 OBD2 Code? (Cylinder 5 Misfire Detected)

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How To Fix P0305 OBD2 Code?
Table of Contents

Many cylinders in your engine work together to keep the crankshaft powered up. When everything is working properly, the components fire in a seamless sequence, ensuring that the crankshaft’s RPM remains constant; however, they occasionally go wrong.

Your system will be unaffected by a single misfire. Misfires that occur frequently or regularly, on the other hand, will result in a severe loss of engine power. In the worst-case scenario, this might be dangerous. As a result, we’ve put together a guide on fixing the P0305 obd2 code to help you prepare for such unusual circumstances.

Definition of P0305 obd2 code

The powertrain control module (PCM) has identified a misfire in one of the engine’s cylinders, as indicated by the OBD-II code P0305. P0305 is a diagnostic problem code that means “Cylinder 5 Misfire Detected.” This signifies that the powertrain control module (PCM) has accumulated enough misfire events on cylinder 5 to store the cylinder’s misfire code. When the crankshaft sensor detects no acceleration of the crankshaft from the cylinder number 5 power stroke, code P0305 is set, indicating that the cylinder is not contributing to engine power.

Definition of P0305 obd2 code

A malfunction with the ignition, fuel or internal engine components is frequently the cause. For example, P0305 indicates that cylinder number 5 is misfiring, which can occur for various causes. A mechanic will need to assess the particular cause for this code to be triggered in your circumstance.

OBD-II Code P0305: Symptoms, Causes & Diagnose

What are the Symptoms of the P0305 obd2 code?

The specific cause of code P0305 can only be determined after a thorough examination. The following are some of the most common causes of the code:

  • Problems with the fuel system (e.g., failed fuel injector or damaged injector driver)
  • Problems with the ignition system (e.g.a, worn spark plug or failed coil pack)
  • Mechanical issues with the engine (e.g., a leaking valve or damaged lifter)

If you notice the following, you should be concerned:

  • Low mileage For long periods
  • Roughness and jerking when you speed, as well as a lack of power
  • If your engine light is on or flashing,
  • Idling in a rough manner
  • Engine dying during stops

What are the causes of the P0305 obd2 code?

The OBD2 code P0305 is a serious one. The drivability concerns linked with the code can make driving your vehicle dangerous. Cylinder 5 is one of the most critical components of the car, and it might misfire for a variety of reasons. Here are a few examples:

  • Because of fouling or insulation cracks, the spark plug for cylinder number 5 is not firing.
  • Cylinder number 5’s ignition coil has stopped working.
  • The ignition spark is leaking to the ground from cylinder number five’s spark plug wire or plug boot.
  • No spark can be generated in cylinder 5 due to oil leakage from the valve cover.

How to Diagnose the P0305 obd2 code?

When you drive your car, check if the engine light is solid and there are no drivability difficulties. If the misfire was a one-time occurrence, the code might not return. If the code reappears, keep an eye on your engine’s performance and continue with the repairs. Code P0305 might be challenging to diagnose because there are many possible causes. Anything from a damaged spark plug to a pricey internal engine issue could be the source of the problem.

As a result, it’s good to look for technical service bulletins (if you have access) that can be useful in the troubleshooting process.

The following are a few steps to figure things out.

  • First, scan codes and document the freeze frame data to validate the problem. Then Clear the engine ETC codes to see if the problem persists.
  • To confirm the misfire to cylinder 5, undertake road tests.
  • Inspect the outside of the ignition coil or plug boot for traces of spark tracking after removing the cylinder five ignition wire. To determine if an oil spill has occurred, look for a leaky valve cover.
  • After removing and checking the spark plug, try a different cylinder to see if the misfire has spread.
  • If there are no issues with ignition, the cylinder compression is checked.

Here are all the tools you will be needing-

All of the tools you’ll need are listed below:

  • Set basic tools (screwdriver, ratchet, socket, etc.)
  • OBD2 scanner
  • Pressure gauge for gasoline
  • Tester for compression
  • Multimeter (digital)

Process of Fixing- 

Process of Fixing- 

Because of the wide range of car models and the various conditions that might cause code P0305, there isn’t a common remedy for this problem, which can make it tough to solve, especially if you’re not an expert.

When a worn-out plug is to blame for the failure, it’s best to replace the entire set of spark plugs to fix a P0305 obd2 error rather than just the one that’s malfunctioning. The leaking valve cover gasket can be replaced, as can the broken coil, plug wires, and plugs, as well as the leaky valve cover gasket.

If the P0305 code reappears, the problem is true with your fuel system. First, using a fuel pressure gauge, check the fuel pressure. Your gasoline pump may be failing if it’s too low. Then, visit the mechanic with your car for a more thorough examination.

Problems with the air-to-fuel ratio frequently cause misfires. These can be due to leaks in the vacuum system and clogged or leaking components in the exhaust system. Regular inspection of your system’s hoses, wiring, and valves might help you avoid problems before they arise.

Typical Diagnosis Errors

Many mechanics immediately replace the spark plugs or ignition coils when a misfire code appears. While these are frequently the source of the problem, you should undertake a comprehensive diagnosis before drawing any judgments.

Some individuals also make the error of not swapping the coil to a different cylinder and rescanning to see if the misfire transfers to another cylinder to determine whether the problem is with the coil. Another blunder to avoid is not isolating the failed part by exchanging one portion at a time with a different cylinder.