why does my Volkswagen Passat B8 (2015-2022) check engine light keep coming on

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, socket set, multimeter, vacuum gauge, and replacement spark plugs or ignition coils if needed.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Address Fault Codes

• Connect the OBD-II scanner and retrieve the diagnostic trouble codes (DTCs).
• Note the codes and consult the vehicle repair manual for specific troubleshooting related to those codes.

3. Replace Spark Plugs and Ignition Coils (if necessary)

• Tools Required: Socket set, torque wrench.
• Remove the engine cover if applicable.
• Disconnect the ignition coil connectors and unbolt the coils.
• Replace spark plugs with new ones, ensuring they are gapped correctly as per specifications.
• Reinstall ignition coils and reconnect connectors.
• Reattach the engine cover.

4. Inspect and Replace Air Intake Components (if necessary)

• Tools Required: Screwdriver set, socket set.
• Remove the air intake duct to access the throttle body.
• Clean the throttle body and replace the air filter if it is dirty.
• Inspect the intake duct for cracks and replace if damaged.

5. Repair or Replace Exhaust Components (if necessary)

• Tools Required: Wrench set, exhaust sealant (if applicable).
• Inspect exhaust manifold and connections for leaks.
• Replace oxygen sensors if tested faulty using a multimeter.

6. Recheck System

• Reconnect the negative battery terminal.
• Clear diagnostic trouble codes using the OBD-II scanner.
• Start the engine and check for the return of the check engine light.