how to fix the P0301 misfire code on my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off.
• Disconnect the battery negative 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 bolt and gently pulling it out.
  2. Remove the spark plug using a spark plug socket and ratchet.
  3. Inspect the spark plug for signs of wear, carbon buildup, or damage. Replace if necessary.
  4. Install a new spark plug, ensuring it is gapped correctly (0.043 inches for Toyota).
  5. Reinstall the ignition coil and secure it with the retaining bolt.

3. Inspect and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. If the ignition coil appears damaged, disconnect the electrical connector and unscrew the coil.
  2. Install a new ignition coil in the reverse order of removal.
  3. Reconnect the electrical connector securely.

4. Check and Replace Fuel Injector (if necessary)

• Sub-steps:
  1. Disconnect the fuel line and electrical connector from the fuel injector in cylinder 1.
  2. Remove the injector using appropriate tools.
  3. Test the injector's resistance using a multimeter; replace if it is outside the specified range.
  4. Install the new fuel injector and reconnect the fuel line and electrical connector.

5. Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1 and attach a compression gauge.
  2. Crank the engine for a few seconds and record the compression reading.
  3. Compare the reading to the manufacturer's specifications (usually around 180 psi).
  4. If compression is low, further engine diagnostics may be needed to identify internal damage.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Spark plug socket
• Ratchet and extensions
• Compression gauge
• Multimeter
• Screwdriver set

Parts Required:

• Spark plugs
• Ignition coil (if faulty)
• Fuel injector (if faulty)