how to fix P0301 misfire code on Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather necessary tools and safety equipment.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plug

1. Remove the ignition coil from cylinder 1:
   • Unplug the electrical connector.
   • Remove the mounting bolts using a socket set.
2. Take out the spark plug with a spark plug socket:
   • Inspect for wear or damage.
   • Replace with a new spark plug if necessary (check gap specifications).
3. Reinstall the spark plug and ignition coil:
   • Torque the spark plug to manufacturer's specifications (usually around 13-16 ft-lbs).

3. Check and Replace Ignition Coil (if necessary)

1. If the spark plug is in good condition, test the ignition coil:
   • Use an ohmmeter to check for the correct resistance (usually around 0.4 to 0.6 ohms for primary winding).
2. If the ignition coil is defective, replace it with a new one:
   • Align the coil properly and secure it with screws.
   • Reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

1. Remove the fuel rail:
   • Disconnect the fuel line using a fuel line disconnect tool (be cautious of fuel spills).
   • Unbolt the fuel rail from the intake manifold.
2. Inspect the fuel injector for clogs or malfunction:
   • Clean using fuel injector cleaner or replace if necessary.
3. Reinstall the fuel rail ensuring proper alignment and sealing.

5. Verify Engine Compression

1. If misfire persists, perform a compression test:
   • Remove spark plug and insert a compression gauge into cylinder 1.
   • Crank the engine and record the pressure (should be within specification, typically 180-200 psi).
2. If compression is low, further investigation into engine internals is required.