how to fix P0301 misfire code on my Toyota Highlander XU70 (2020-Present)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to avoid electrical shocks.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Multimeter
• Vacuum gauge (if needed)

2. Inspect and Replace Spark Plug

1. Locate the spark plug for cylinder 1.
2. Remove the ignition coil by unscrewing any retaining bolts and disconnecting the electrical connector.
3. Unscrew the spark plug using a spark plug socket and ratchet.
4. Inspect the spark plug for wear, carbon buildup, or damage. Replace it if necessary.
5. Install the new spark plug with the specified torque (typically 13-16 lb-ft for most Toyota engines).
6. Reattach the ignition coil and ensure it is securely fastened.

3. Inspect and Replace Ignition Coil

1. If the ignition coil is defective, remove it as described above.
2. Install a new ignition coil, ensuring it is seated properly.
3. Reconnect the electrical connector and any retaining bolts.

4. Check and Clean Fuel Injector

1. Disconnect the fuel injector connector for cylinder 1.
2. Using a multimeter, test the resistance of the injector to ensure it is within specifications (typically 12-16 ohms).
3. If the injector is faulty, replace it. If not, use an injector cleaner to clean the injector.
4. Reconnect the fuel injector connector.

5. Perform Compression Test

1. Remove the spark plug from cylinder 1 (if not already done).
2. Insert the compression tester into the spark plug hole and crank the engine.
3. Record the compression reading. It should be within the manufacturer’s specified range (usually around 140-200 psi).
4. If the reading is low, consider further diagnostics for possible internal engine issues.