what does code P0303 mean for my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Tools Required:
  • OBD-II scanner
  • Socket set
  • Torque wrench
  • Compression tester
  • Multimeter
• Safety Warnings: Disconnect the battery before working on electrical systems.

2. Inspect and Replace Spark Plug

• Remove the engine cover if necessary.
• Disconnect the ignition coil connector.
• Remove the ignition coil from cylinder 3 using the socket set.
• Take out the spark plug using a spark plug socket.
• Inspect the spark plug for wear; replace if necessary with OEM specifications (usually NGK or Denso).
• Reinstall the spark plug and torque it to the manufacturer's specifications (typically 13 lb-ft).

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil with a multimeter for resistance.
• If the resistance is out of spec, replace the ignition coil with a new one.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Perform Compression Test

• Remove the spark plug and insert the compression tester into cylinder 3.
• Crank the engine and record the compression reading.
• If compression is below manufacturer specifications (usually around 180 psi), further investigation into piston rings or valves may be needed.

5. Inspect Fuel Injector

• If the ignition coil and spark plug are functional, check the fuel injector for cylinder 3.
• Remove the fuel injector connector and test with a multimeter for proper voltage.
• If the injector is faulty, replace it with an OEM equivalent and ensure proper installation.