how to address the P0301 code in 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

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector cleaning kit.
• Disconnect the negative battery terminal to ensure safety.

2. Replace Spark Plug

1. Remove the ignition coil from cylinder 1 by unscrewing the retaining bolts.
2. Unplug the electrical connector from the ignition coil.
3. Remove the old spark plug using a spark plug socket and ratchet.
4. Inspect the spark plug for signs of wear or fouling.
5. Install a new spark plug, ensuring it is gapped according to manufacturer specifications (typically around 0.030 inches).
6. Reinstall the ignition coil and reconnect the electrical connector.

3. Test and Replace Ignition Coil

1. Using a multimeter, test the resistance of the ignition coil for cylinder 1.
2. If the resistance is outside manufacturer specifications, replace the ignition coil with a new one.
3. Ensure proper installation and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

1. Disconnect the fuel line and electrical connector from the fuel injector in cylinder 1.
2. Remove the injector using the appropriate socket.
3. Clean the injector using a fuel injector cleaning kit, or replace it if necessary.
4. Reinstall the injector, ensuring correct orientation and securing it properly.

5. Perform Compression Test

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 to manufacturer specifications; if low, further investigation into the engine internals may be necessary.