how to fix P0301 code on GMC Sierra T1XX (2019-Present)

Learn how to diagnose and fix P0301 cylinder 1 misfire in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts ahead of time.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the ignition coil wiring harness for cylinder 1.
  3. Remove the ignition coil bolts and take the ignition coil out.
  4. Remove the spark plug using a spark plug socket.
  5. Inspect the spark plug for wear; replace it with a new OEM spark plug if damaged or fouled.
  6. Reinstall the spark plug and ignition coil, ensuring proper torque (typically 12-15 lb-ft).

3. Inspect and Replace Ignition Coil (if needed)

• Sub-steps:
  1. If the ignition coil shows signs of damage (cracks, corrosion), replace it with a new OEM coil.
  2. Reconnect the ignition coil wiring harness.
  3. Reinstall the engine cover (if removed).

4. Check and Replace Fuel Injector (if needed)

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Remove the fuel rail (may require removing additional components).
  3. Replace the fuel injector for cylinder 1 with a new OEM injector.
  4. Reinstall the fuel rail, ensuring proper alignment and torque specifications.

5. Test and Reassemble

• Sub-steps:
  1. Reconnect the battery terminal.
  2. Start the engine and let it idle to check for smooth operation.
  3. Scan for error codes again to confirm that the P0301 code is cleared.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Spark plug socket
• Fuel injector puller (if needed)

Parts Required:

• OEM spark plug
• OEM ignition coil (if replaced)
• OEM fuel injector (if replaced)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect the battery before working on electrical components.
• Allow the engine to cool before removing any components to avoid burns.