my GMC Sierra T1XX (2019-Present) has a check engine light and loses power, what to do?

Learn how to diagnose and fix engine power loss and check engine light issues in GMC Sierra T1XX (2019-Present). Step-by-step guide included.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Addressing Fault Codes

• Sub-steps:
  1. Reconnect the OBD-II scanner and document any error codes.
  2. Clear the codes and perform a test drive to see if they return.
  3. Investigate codes related to the fuel system, ignition, or sensors.

3. Fuel System Inspection

• Sub-steps:
  1. Attach a fuel pressure gauge to the fuel rail.
  2. Start the engine and observe the fuel pressure readings; consult manufacturer specifications.
  3. If pressure is low, check the fuel pump and filter for blockages or failure and replace if necessary.

4. Ignition System Check

• Sub-steps:
  1. Remove the spark plugs and inspect for wear or carbon buildup.
  2. Replace any damaged or worn spark plugs with OEM equivalents, torquing to specification.
  3. Check ignition coils for proper operation using a multimeter; replace if faulty.

5. Throttle Body Cleaning

• Sub-steps:
  1. Remove the throttle body assembly from the intake manifold.
  2. Clean the throttle plate and bore with throttle body cleaner and a soft brush.
  3. Reinstall the throttle body and reconnect all electrical connectors.

6. Vacuum Leak Check

• Sub-steps:
  1. Inspect all vacuum hoses for cracks or disconnections.
  2. Utilize a smoke machine or spray soapy water to identify leaks.
  3. Replace any damaged hoses and ensure all connections are secure.