GMC Sierra T1XX (2019-Present) P0302 error code, what does it mean?

Learn how to diagnose and fix P0302 cylinder 2 misfire in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and materials.
• Disconnect the vehicle battery to ensure safety during repairs.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plug

• Remove the engine cover if applicable.
• Disconnect the ignition coil connector for cylinder 2.
• Remove the ignition coil from cylinder 2 using a socket set.
• Inspect the spark plug for wear or damage; replace if necessary.
• Install a new spark plug (torque to manufacturer specifications, usually around 13-15 lb-ft).
• Reconnect the ignition coil and any connectors.

3. Check and Replace Ignition Coil (if needed)

• If the spark plug is in good condition, test the ignition coil's resistance using a multimeter.
• If the resistance is outside of the manufacturer's specifications, replace the ignition coil.
• Reinstall the ignition coil and reconnect the wiring harness.

4. Inspect Fuel Injector

• Disconnect the fuel injector connector for cylinder 2.
• Use a fuel injector tester to check for proper operation (or replace if faulty).
• Reconnect the fuel injector and ensure all connections are secure.

5. Perform Compression Test

• Remove the spark plug from cylinder 2.
• Insert the compression gauge into the spark plug hole.
• Crank the engine and record the compression reading.
• Compare the reading to the manufacturer’s specifications; if low, further investigation is needed.