how to fix P0301 misfire code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, noid light, compression tester.
• Ensure the engine is cool and disconnect the battery before starting the repair.

2. Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Remove the ignition coil by unscrewing the mounting bolts.
  4. Pull out the spark plug using a spark plug socket.
  5. Inspect the old spark plug for wear or damage.
  6. Install a new spark plug, ensuring the gap is set to manufacturer specifications (typically around 0.043 inches).
  7. Reinstall the ignition coil and reconnect the connector.

3. Replace Ignition Coil (if necessary)

• Sub-steps:
  1. Follow steps 1-3 from the spark plug replacement.
  2. Remove the ignition coil from cylinder 1.
  3. Install the new ignition coil and torque it to manufacturer specifications (usually around 7.2 ft-lbs).
  4. Reconnect the ignition coil connector.

4. Test Fuel Injector

• Sub-steps:
  1. Use a noid light to check if the fuel injector for cylinder 1 is receiving a signal.
  2. If no signal is detected, trace the wiring back to the engine control unit (ECU) for faults.
  3. If the injector fails to operate, replace it with a new fuel injector, ensuring proper installation and torque.

5. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert a compression tester into the spark plug hole.
  3. Crank the engine and note the compression reading (should be within manufacturer specifications).
  4. If compression is low, further investigation into piston rings, valves, or head gasket may be necessary.