why does my Toyota Highlander have a check engine code P0303

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Remove Ignition Coil and Spark Plug

1. Remove the engine cover, if applicable.
2. Disconnect the electrical connector from the ignition coil for cylinder 3.
3. Unbolt the ignition coil using a socket set and carefully remove it from the spark plug.
4. Use a spark plug socket to remove the spark plug from cylinder 3.

3. Inspect and Replace Components

1. Inspect the spark plug for signs of wear, such as carbon buildup or damage. Replace if necessary.
2. Test the ignition coil using a multimeter for resistance; replace if it does not meet specifications.
3. If suspected, check the fuel injector for cylinder 3 by performing a resistance test and cleaning or replacing it if clogged.

4. Reassemble Components

1. Install the new or inspected spark plug into cylinder 3 and torque to manufacturer specifications (typically around 13 ft-lbs).
2. Reinstall the ignition coil and secure it with bolts, ensuring the electrical connection is reconnected.
3. Reinstall the engine cover if it was removed.

5. Final Steps

• Reconnect the battery terminals.
• Clear the check engine codes using the OBD-II scanner.