how to fix the P0301 misfire code on my Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, torque wrench, multimeter, compression tester.
• Ensure the vehicle is parked on a level surface, and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the ignition coil from cylinder 1 by unscrewing the retaining bolts.
  2. Pull the ignition coil out and disconnect the electrical connector.
  3. Remove the spark plug using a socket and ratchet.
  4. Inspect the spark plug for wear; replace it if it shows signs of fouling or excessive wear.
  5. Install the new spark plug, tightening it to the manufacturer’s specified torque (typically around 13-16 lb-ft).
  6. Reinstall the ignition coil and reconnect the electrical connector.

3. Test Fuel Injector

• Sub-steps:
  1. Remove the fuel injector connector for cylinder 1.
  2. Use a multimeter to check the resistance of the fuel injector; compare it to specifications (usually around 12-16 ohms).
  3. If out of range, replace the fuel injector.
  4. If the injector is good, reconnect it properly.

4. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug for cylinder 1.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine for several seconds to obtain a compression reading.
  4. Compare the readings to manufacturer specifications (typically around 180-210 psi).
  5. If compression is low, further investigation into the engine internals may be required.