how to fix P0300 code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, torque wrench, multimeter, fuel pressure gauge.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the ignition coil cover (if applicable) using the socket set.
  2. Disconnect the ignition coils and remove them from the spark plugs.
  3. Remove the spark plugs using a spark plug socket and inspect for wear.
  4. Replace worn or damaged spark plugs with new ones, ensuring they are gapped correctly (refer to the vehicle’s specifications).
  5. Reinstall ignition coils and cover.

3. Check and Replace Ignition Coils

• Sub-steps:
  1. If spark plugs are in good condition, test ignition coils with a multimeter for resistance (refer to specifications).
  2. Replace any faulty ignition coils with new OEM or quality aftermarket parts.
  3. Reconnect all electrical connections securely.

4. Inspect Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail to check for proper fuel pressure.
  2. If pressure is low, inspect the fuel pump and filter for clogs or damage.
  3. Clean or replace clogged injectors as necessary.
  4. Reconnect all lines and ensure there are no leaks.

5. Check for Vacuum Leaks

• Sub-steps:
  1. Inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to identify leaks.
  3. Repair or replace any damaged hoses.

6. Perform Compression Test

• Sub-steps:
  1. Remove all spark plugs to avoid damage during testing.
  2. Insert compression tester into each cylinder.
  3. Crank the engine and record pressure readings; compare against manufacturer specifications.
  4. Address any cylinders with low compression by inspecting valves and piston rings.