why does my Toyota RAV4 Fifth Generation (2019-present) have a check engine light with code P0303

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect Ignition Components

• Sub-steps:
  • Remove the engine cover (if applicable) using a socket set.
  • Unscrew and carefully remove the ignition coil from cylinder 3.
  • Inspect the spark plug condition; replace it if worn or fouled.
  • Reinstall a new spark plug (torque to manufacturer specifications, usually around 13 lb-ft).
  • Replace or repair the ignition coil if it shows signs of damage or wear.

3. Inspect Fuel Injector

• Sub-steps:
  • Disconnect the fuel injector connector for cylinder 3.
  • Remove the fuel injector using a fuel injector puller if necessary.
  • Inspect for carbon buildup or blockages in the injector.
  • Clean the injector using a specialized cleaner or replace it if damaged.

4. Check for Vacuum Leaks

• Sub-steps:
  • Inspect all vacuum hoses connected to the intake manifold.
  • Replace any cracked or disconnected hoses.
  • Use a smoke machine to detect any hidden leaks in the intake system.

5. Compression Test

• Sub-steps:
  • Remove the spark plug from cylinder 3.
  • Insert the compression gauge into the spark plug hole.
  • Crank the engine several times and note the compression reading.
  • Compare the reading to the manufacturer's specifications (typically around 180-200 psi).
  • If the reading is low, further diagnostics may be necessary for potential internal engine issues.