why does my GMC Sierra T1XX (2019-Present) stall when I come to a stop?

Learn how to diagnose and fix stalling issues in GMC Sierra T1XX (2019-Present). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and engage the parking brake.
• Disconnect the battery to prevent electrical shock.

2. Clean the Throttle Body

• Remove the air intake duct to access the throttle body.
• Use throttle body cleaner and a soft cloth to clean the inside of the throttle body.
• Reassemble the air intake duct securely.

3. Check and Replace Fuel Filter

• Locate the fuel filter (if applicable) in the fuel line.
• Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect the fuel lines and remove the old fuel filter.
• Install the new fuel filter in the correct orientation and reconnect the fuel lines.
• Replace the fuel pump fuse.

4. Inspect and Clean the IAC Valve

• Locate the IAC valve, typically mounted on the throttle body.
• Remove the IAC valve and inspect it for carbon deposits.
• Clean the IAC valve using a suitable cleaner.
• Reinstall the IAC valve and ensure it is secure.

5. Test and Replace MAF Sensor (if necessary)

• Disconnect the MAF sensor electrical connector.
• Check the sensor with a multimeter according to the specifications in the service manual.
• If the MAF sensor is faulty, replace it with a new one and reconnect the electrical connector.