how to fix the P0304 code in my Ram 1500 DT (2019-Present)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Ram 1500 DT. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench
• Remove the ignition coil by unscrewing it and disconnecting the electrical connector.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for fouling, wear, or damage; replace if necessary.
• Torque the new spark plug to the manufacturer's specification (typically around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Check the ignition coil for signs of damage or wear.
• If faulty, install a new ignition coil by reversing the removal process.
• Ensure the electrical connector is securely attached.

4. Test Fuel Injector

• Tools Required: Noid light or multimeter
• Disconnect the fuel injector connector.
• Use a noid light to check for signal; if it doesn’t flash, further inspect the wiring or the ECU.
• If injector is faulty, replace it following the manufacturer's guidelines.

5. Compression Test

• Tools Required: Compression tester
• Remove the spark plug from cylinder 4.
• Insert the compression tester and crank the engine.
• Record the pressure; it should be within the manufacturer’s specifications (typically around 150-200 psi).
• If compression is low, further investigate cylinder health (valves, piston rings).

6. Reassemble and Reconnect Battery

• Reinstall all components in reverse order of removal.
• Reconnect the negative battery terminal.