how to fix the check engine light and code P0301 in my Toyota Camry

Solution

1. Preparation

• Gather tools and materials.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool if it has been running.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the ignition coil cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Remove the ignition coil using a socket set.
  4. Extract the spark plug using a spark plug socket.
  5. Inspect the spark plug for wear, carbon buildup, or damage.
  6. Replace the spark plug with a new one, ensuring it meets manufacturer specifications (typically NGK or Denso).
  7. Reinstall the ignition coil and reconnect the connector.

3. Inspect and Replace Ignition Coil

• Sub-steps:
  1. If the spark plug is fine, visually inspect the ignition coil for cracks or wear.
  2. Test the resistance of the ignition coil using a multimeter; compare readings to manufacturer specifications.
  3. If faulty, replace the ignition coil with a new OEM or quality aftermarket part.
  4. Reinstall the ignition coil and reconnect the electrical connector.

4. Check Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Use a noid light to check for signal to the injector when the engine is cranked.
  3. If no signal is present, inspect the wiring and connectors.
  4. If the injector is not operational, replace it with a new one.
  5. Reconnect all connectors and ensure they are secured.

5. Perform Compression Test

• Sub-steps:
  1. Remove all spark plugs for easier cranking.
  2. Insert the compression gauge into the spark plug hole for cylinder 1.
  3. Crank the engine for several seconds and record the compression reading.
  4. Compare the reading against the engine specifications.
  5. If compression is low, further diagnosis of internal engine issues may be required.