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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Park the vehicle on a level surface, engage the parking brake, and disconnect the battery.

2. Replace Spark Plug

• Tools Required: Socket set, spark plug socket, torque wrench
• Remove the engine cover if applicable.
• Remove the ignition coil by disconnecting the electrical connector and unscrewing the mounting bolts.
• Use a spark plug socket to remove the old spark plug from cylinder one.
• Inspect the new spark plug for proper gap (typically 0.043 inches for Toyota).
• Install the new spark plug and tighten it to the manufacturer’s specified torque (around 13 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test Ignition Coil

• Tools Required: Multimeter
• Disconnect the ignition coil connector.
• Set the multimeter to measure resistance and check primary and secondary resistance as per specifications (primary: around 0.4-2.0 ohms; secondary: around 6,000-15,000 ohms).
• If the ignition coil is defective, replace it with a new one.

4. Check Compression

• Tools Required: Compression tester
• Remove the spark plug from cylinder one.
• Insert the compression tester into the spark plug hole.
• Crank the engine for a few seconds and note the compression reading (should be around 180 psi; consult service manual for specifics).
• If compression is low, diagnose further for potential causes (valve issues, head gasket failure).

5. Inspect Fuel Injector

• Tools Required: Fuel injector cleaner or replacement injector
• Disconnect the fuel injector connector.
• Check for proper voltage and ground at the injector using a multimeter.
• If suspecting a clogged injector, use an injector cleaner or replace the injector if necessary.