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 necessary tools and parts.
• Ensure the engine is cool before beginning work.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug (if necessary)

• Sub-steps:
  1. Remove the ignition coil from cylinder 1 by unscrewing any retaining bolts or clips.
  2. Disconnect the electrical connector from the ignition coil.
  3. Remove the spark plug using a spark plug socket and ratchet.
  4. Inspect the old spark plug for damage, fouling, or incorrect gap.
  5. Install a new spark plug, ensuring it is gapped according to manufacturer specifications (usually around 0.030 inches).
  6. Reattach the ignition coil and connect the electrical connector.

3. Inspect and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. If the ignition coil appears damaged, remove it by unscrewing the mounting bolts.
  2. Install a new ignition coil, ensuring it is properly seated on the spark plug.
  3. Reconnect the electrical connector securely.

4. Test Fuel Injector (if necessary)

• Sub-steps:
  1. Disconnect the fuel injector connector from cylinder 1.
  2. Use a multimeter to test for proper resistance (check manufacturer specifications).
  3. If the injector is faulty, replace it by removing the fuel rail if needed.
  4. Install the new fuel injector and reconnect the connector.

5. Compression Test (if necessary)

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert a compression gauge into the spark plug hole.
  3. Crank the engine and record the compression reading.
  4. Compare the reading with manufacturer specifications; low compression may indicate internal engine issues.