what does it mean if my GMC Sierra T1XX (2019-Present) has a P0301 code?

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.
• Disconnect the negative battery cable to prevent electrical shorts.
• Ensure the engine is cool before starting work.

2. Inspect and Replace Ignition Components

1. Remove the engine cover if applicable.
2. Disconnect the ignition coil connector for cylinder 1.
3. Remove the ignition coil from cylinder 1 using a socket set.
4. Inspect the spark plug: if worn or fouled, replace it with a new one (check gap specifications).
5. Install the new spark plug and torque it to the manufacturer's specifications (typically around 13-15 lb-ft).
6. Reinstall the ignition coil and reconnect the connector.

3. Clean or Replace Fuel Injector

1. Disconnect the fuel injector connector for cylinder 1.
2. Remove the fuel rail if necessary to access the injector.
3. Use a fuel injector cleaner if the injector is clogged; otherwise, replace it with a new injector.
4. Reinstall the fuel rail and reconnect the injector connector.

4. Perform Compression Test (if mechanical issues suspected)

1. Remove the spark plug from cylinder 1.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for a few seconds and record the compression reading.
4. Compare the reading with the manufacturer's specifications (should typically be around 120-180 psi).
5. If the compression is low, further investigation is needed (valve issues, piston rings, etc.).