why does my GMC Sierra T1XX (2019-Present) check engine light keep coming on

Learn how to diagnose and fix the recurring check engine light issue in GMC Sierra T1XX (2019-Present). Step-by-step guide with diagnostic procedures.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during the repair.
• Allow the engine to cool if it has been running.

2. Addressing Trouble Codes

• Use the OBD-II scanner to read the trouble codes.
• Research the specific codes to determine the affected system or component.
• Clear the codes and see if they return after a short test drive.

3. Inspect and Repair Fuel System

• Fuel Cap Check:
  • Remove and inspect the fuel cap for cracks or damage.
  • Replace if necessary.
• Fuel Lines:
  • Inspect fuel lines for leaks or damage.
  • Replace any damaged lines.

4. Air Intake System

• Check Air Filter:
  • Remove the air filter and inspect for dirt or blockage.
  • Replace the air filter if it is dirty.
• Inspect Intake Hoses:
  • Check for cracks or loose connections in the intake hoses.
  • Replace any damaged hoses.

5. Exhaust System Inspection

• Visual Inspection:
  • Inspect the exhaust for rust, holes, or loose clamps.
  • Repair or replace any damaged sections.
• Oxygen Sensors:
  • Check and test the oxygen sensors for proper function.
  • Replace any faulty sensors.

6. Ignition System Maintenance

• Spark Plugs:
  • Remove and inspect spark plugs for wear or carbon buildup.
  • Replace with OEM specifications if necessary.
• Ignition Coils:
  • Test ignition coils for proper resistance.
  • Replace any coils that are out of specification.