how to diagnose P0301 misfire code in Ford Explorer Fifth Generation (2011-2019)

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down if it has been running.

2. Inspect and Replace Spark Plug

• Remove the ignition coil for cylinder 1:
  • Unscrew the bolts securing the ignition coil.
  • Gently pull the coil straight out from the spark plug.
• Remove the spark plug using a spark plug socket and ratchet:
  • Inspect for wear, carbon buildup, or damage.
  • Replace with a new spark plug (gapping to manufacturer specifications).
• Reinstall the ignition coil.
• Torque the ignition coil bolts to the manufacturer's specification (usually around 7-10 lb-ft).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil:
  • Check the coil resistance using a multimeter; compare readings to manufacturer specifications.
  • If it is faulty, remove the ignition coil and replace it with a new one.
• Reconnect wiring to the new ignition coil.

4. Test Fuel Injector

• Remove the connector from the fuel injector for cylinder 1:
  • Check for any corrosion or damage.
• Perform a resistance test on the fuel injector to ensure it is functioning (should generally be around 12-16 ohms).
• If faulty, replace the fuel injector with a new one.
• Reinstall the connector securely.

5. Verify and Clear Codes

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Use the OBD-II scanner to check for any active codes and clear the P0301 code.
• Test drive the vehicle to ensure the misfire does not return.