how to fix Ram 1500 DT (2019-Present) misfire code P0301

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, fuel pressure gauge, noid light, compression tester.
• Disconnect the battery to prevent any electrical issues.

2. Replace Spark Plug

• Remove the ignition coil by unscrewing the bolts securing it.
• Gently pull the ignition coil off the spark plug.
• Use a spark plug socket to remove the old spark plug from cylinder 1.
• Inspect the spark plug for signs of fouling or damage.
• Install a new spark plug, ensuring it matches OEM specifications (usually gap is between 0.040-0.045 inches).
• Torque the spark plug to manufacturer specifications (typically around 13-15 ft-lbs).
• Reinstall the ignition coil and secure it with bolts.

3. Test or Replace Ignition Coil

• If misfire persists, check the ignition coil's resistance using a multimeter:
  • Primary resistance should be between 0.4 to 0.6 ohms.
  • Secondary resistance should be between 6,000 to 15,000 ohms.
• If the coil is out of spec, replace it with a new one.
• Reconnect the ignition coil and ensure it is securely fastened.

4. Inspect Fuel Injector

• Disconnect the fuel injector connector for cylinder 1.
• Use a noid light to check for proper electrical signal to the injector while cranking the engine.
• If no signal is present, check wiring and connectors for damage.
• If the signal is present but the injector is not functioning, replace the fuel injector.

5. Compression Test (if necessary)

• If misfire continues, perform a compression test:
  • Remove spark plugs from all cylinders.
  • Insert the compression tester into the spark plug hole of cylinder 1.
  • Crank the engine for several revolutions and record the compression reading.
  • Compare the reading to the specifications provided in the service manual (typically around 120-200 psi).
• If compression is low, diagnose further for potential internal engine issues.