what does it mean if my Toyota Highlander Third Generation (2014-2019) has a P0301 code?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the ignition coil from cylinder 1.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for wear or fouling; replace if necessary.
• Apply dielectric grease to the spark plug threads and install a new or cleaned spark plug, torquing to manufacturer specifications (typically around 13-16 lb-ft).
• Reinstall the ignition coil.

3. Inspect and Replace Ignition Coil (if necessary)

• Tools Required: Socket set, torque wrench.
• If the ignition coil appears damaged or faulty, remove it from cylinder 1.
• Replace with a new ignition coil, ensuring it is seated properly.
• Torque the coil mounting bolts to manufacturer specifications.

4. Test Fuel Injector

• Tools Required: Noid light or multimeter.
• Disconnect the fuel injector connector for cylinder 1.
• Use a noid light to check for pulse when the engine is cranked; if no pulse, inspect the wiring.
• If necessary, replace the fuel injector with a new one, ensuring proper seating and connection.

5. Conduct Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester and crank the engine to get a reading.
• If compression is below manufacturer specifications, further diagnosis of the engine internals may be required.