how to troubleshoot P0301 misfire code in my Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plug

• Tools Needed: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil by unscrewing the retaining bolts and disconnecting the electrical connector.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for fouling, wear, or damage. Replace with OEM or equivalent spark plug if necessary.
• Torque the new spark plug to manufacturer's specifications (typically around 13-16 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test and Replace Ignition Coil (if necessary)

• Tools Needed: Multimeter.
• If the spark plug replacement does not resolve the issue, test the ignition coil by measuring the resistance across the primary and secondary terminals using a multimeter.
• If out of specification, replace the ignition coil with a new OEM or equivalent part.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Inspect Fuel Injector

• Tools Needed: Noid light or fuel injector tester.
• Disconnect the fuel injector connector for cylinder 1.
• Connect the noid light or fuel injector tester to the connector.
• Crank the engine to check for proper signal and operation.
• If no signal is detected, check the wiring and PCM signal.
• If the injector is faulty, replace it with a new OEM or equivalent fuel injector.

5. Perform Compression Test

• Tools Needed: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole and crank the engine.
• Compare the compression reading to the manufacturer’s specifications (usually around 180-200 psi). If low, it may indicate internal engine issues (valve seats, piston rings).
• If necessary, repair or replace affected components.