how to fix P0303 code in Toyota Highlander Third Generation (2014-2019)

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. Replace Spark Plug and Ignition Coil

1. Remove Engine Cover (if applicable).
   • Use a socket set to remove bolts securing the engine cover.
2. Remove Ignition Coil for cylinder 3.
   • Disconnect the electrical connector from the ignition coil.
   • Unscrew the bolts holding the ignition coil in place and remove it.
3. Replace Spark Plug in cylinder 3.
   • Use a spark plug socket to unscrew the old spark plug.
   • Check the gap on the new spark plug and adjust if necessary.
   • Install the new spark plug and torque it to 13 lb-ft (18 Nm).
4. Install New Ignition Coil.
   • Position the new ignition coil over the spark plug and secure it with bolts.
   • Reconnect the electrical connector.

3. Check and Replace Fuel Injector (if necessary)

1. Remove Fuel Rail.
   • Relieve fuel pressure by removing the fuel pump fuse and running the engine until it stalls.
   • Disconnect fuel lines and unbolt the fuel rail.
2. Replace Injector for Cylinder 3.
   • Remove the old fuel injector from the fuel rail.
   • Install the new injector and ensure it seats properly.
3. Reinstall Fuel Rail and reconnect fuel lines.

4. Perform Compression Test

1. Remove Spark Plug from cylinder 3 again.
2. Insert Compression Tester into the spark plug hole.
3. Crank the Engine and record the compression reading.
   • Ensure the reading is within the manufacturer’s specified range (usually around 150-200 psi).
4. Reinstall Spark Plug and ignition coil after testing.