why does my BMW X5 G05 (2019-2024) have a rough idle when cold?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during repairs.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if applicable.
• Disconnect the ignition coils from the spark plugs.
• Use the spark plug socket to remove the old spark plugs.
• Inspect the plugs for wear; replace them if necessary.
• Install new spark plugs and torque them to the manufacturer's specification (typically around 15-20 Nm).
• Reconnect the ignition coils and replace the engine cover.

3. Test and Replace Coolant Temperature Sensor

• Tools Required: Multimeter, socket set.
• Locate the coolant temperature sensor (usually near the thermostat housing).
• Disconnect the electrical connector from the sensor.
• Use the multimeter to test the sensor's resistance against the specifications in the service manual.
• If out of spec, replace the coolant temperature sensor.
• Reconnect the electrical connector.

4. Clean or Replace Idle Air Control Valve

• Tools Required: Screwdrivers, cleaning solvent.
• Locate the idle air control valve (IAC) on the throttle body.
• Disconnect the electrical connector and remove the valve from its mounting.
• Clean the valve with a suitable cleaning solvent to remove any carbon buildup.
• If the valve is damaged or excessively dirty, replace it with a new one.
• Reinstall the IAC valve and reconnect the electrical connector.

5. Inspect and Repair Air Intake System

• Tools Required: Screwdrivers, hose clamps.
• Inspect the air intake hoses for cracks or leaks.
• Check the air filter for cleanliness; replace if dirty.
• Ensure that all connections in the air intake system are tight and secure.