how to diagnose P0301 misfire code in my Honda CR-V Fifth Generation (2017-2022)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, compression tester, multimeter, fuel injector cleaning kit.
• Ensure the vehicle is parked on a level surface, the engine is cool, and the battery is disconnected before beginning work.

2. Inspect Ignition System

• Remove the engine cover (if applicable) using a socket set.
• Disconnect the ignition coil connector for cylinder 1 and remove the ignition coil.
• Inspect the spark plug for wear, carbon buildup, or damage; replace if necessary.
• Check the ignition coil for proper operation using a multimeter (measure the primary and secondary resistance). Replace if out of specification.

3. Check Fuel Injector

• Disconnect the fuel injector connector for cylinder 1.
• Use a multimeter to check the injector's resistance; replace if out of specification.
• If the injector is fouled, use a fuel injector cleaning kit to clean it before reinstallation.

4. Perform Compression Test

• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole and crank the engine for a few seconds.
• Record the compression reading and compare it to the manufacturer's specifications; if low, further investigation into the engine's internals is required.

5. Inspect for Vacuum Leaks

• With the engine running, use a smoke machine or spray carburetor cleaner around the intake manifold, vacuum hoses, and throttle body to identify any vacuum leaks.
• If a leak is detected, repair or replace the affected components.

6. Check Timing

• Remove the timing cover (if necessary) to visually inspect the timing belt/chain for wear or misalignment.
• Verify the timing marks are aligned according to the manufacturer's specifications. Adjust if necessary.