how to fix P0301 code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Spark Plug

1. Remove the engine cover (if applicable) using a socket set.
2. Remove the ignition coil for cylinder 1 by unscrewing the mounting bolts and disconnecting the electrical connector.
3. Using a spark plug socket, remove the spark plug from cylinder 1.
4. Inspect the spark plug for wear; replace it if necessary with a new spark plug specified for the vehicle. Torque to manufacturer specifications (typically around 13 lb-ft).
5. Reinstall the ignition coil and secure it with bolts. Reconnect the electrical connector.

3. Inspect and Replace Ignition Coil

1. If the ignition coil was found to be faulty during inspection, remove it as previously described.
2. Install the new ignition coil, ensuring it is seated correctly. Torque the mounting bolts to manufacturer specifications (typically around 8.7 lb-ft).
3. Reconnect the electrical connector to the new ignition coil.

4. Check Fuel Injector (if required)

1. If the injector was suspected to be faulty, disconnect the fuel injector connector.
2. Remove the fuel rail if necessary to access the injector, taking care to relieve fuel pressure beforehand.
3. Replace the injector if it is clogged or malfunctioning, ensuring to lubricate the O-ring with clean engine oil before installation.
4. Reassemble the fuel rail and reconnect all connectors.