my BMW X5 F15 (2014-2019) stalls at red lights, what could be the issue?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Clean or Replace Throttle Body

• Tools Required: Throttle body cleaner, rags, socket set, torque wrench
• Remove the air intake duct connected to the throttle body.
• Use throttle body cleaner to clean the inside of the throttle body.
• Reinstall the duct and ensure all connections are secure.

3. Inspect and Clean the Idle Air Control Valve (IAC)

• Tools Required: Socket set, screwdriver, cleaner
• Locate the IAC valve, typically found on or near the throttle body.
• Detach the electrical connector and remove the valve from the intake manifold.
• Clean the valve with appropriate cleaner and inspect for wear. Replace if necessary.
• Reinstall the IAC valve and reconnect the electrical connector.

4. Check for Vacuum Leaks

• Tools Required: Smoke machine (optional), hose clamps
• Visually inspect all vacuum hoses for cracks or disconnections.
• If available, use a smoke machine to identify hidden leaks in the intake system.
• Replace any damaged hoses or fittings.

5. Fuel System Inspection

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position (do not start the engine) to check the pressure.
• If the pressure is low, inspect the fuel pump and filter for blockages or failure.

6. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear any diagnostic trouble codes (DTCs).
• Start the vehicle and allow it to idle to ensure the issue is resolved.