how to diagnose P0301 code on my Toyota Tacoma N300 (2016-Present)?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before accessing engine components.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, spark plug gap tool, torque wrench
• Remove the ignition coil for cylinder 1 using a socket wrench.
• Carefully pull out the spark plug using a spark plug socket.
• Inspect the spark plug for wear or fouling; if damaged, replace with a new spark plug.
• Ensure the new spark plug is gapped correctly according to specifications (usually around 0.044 inches for Toyota).
• Reinstall the spark plug and torque it to the manufacturer’s specification (usually around 13 lb-ft).
• Reattach the ignition coil.

3. Test Ignition Coil

• Tools Required: Multimeter
• Disconnect the connector from the ignition coil.
• Use a multimeter to test the primary and secondary resistance of the coil; compare the readings to manufacturer specifications.
• If the ignition coil is faulty, replace it with a new one and reconnect.

4. Inspect and Test Fuel Injector

• Tools Required: Fuel injector tester, basic hand tools
• Remove the fuel injector connector for cylinder 1.
• Use a fuel injector tester to check the operation; listen for clicking sounds indicating proper function.
• If the injector is faulty or clogged, replace it with a new injector.

5. Conduct Compression Test

• Tools Required: Compression tester
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole.
• Crank the engine and record the compression reading; compare with specifications (usually between 180-200 psi).
• If compression is low, further investigation is required for potential internal engine issues.