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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent any electrical shock.

2. Addressing Fault Codes

• Use the OBD-II scanner to clear the stored error codes after repairs.
• If the same code returns, further investigation into the specific fault is required.

3. Inspect and Replace Components

• Spark Plugs and Ignition Coils

  • Remove the engine cover if applicable.
  • Disconnect the electrical connectors from the ignition coils.
  • Remove the ignition coil bolts and lift out the coils.
  • Replace spark plugs with OEM or equivalent parts, ensuring proper gap.
  • Reinstall ignition coils and secure with bolts.

• Vacuum Leaks

  • Check all vacuum hoses for cracks or disconnections.
  • Replace any damaged hoses with OEM parts.
  • Reconnect all hoses securely.

• Evaporative Emission Control System (EVAP)

  • Inspect the gas cap for wear; replace if necessary.
  • Check EVAP canister and purge valve for blockages or malfunctions.

4. Fuel System Maintenance

• Replace the fuel filter if it's clogged or hasn't been changed per the maintenance schedule.
• Check fuel pressure using a fuel pressure gauge; replace the fuel pump if pressure is below specifications.

5. Final Steps

• Reconnect the battery.
• Start the engine and allow it to idle; listen for irregular sounds.
• Test drive the vehicle to ensure the check engine light does not reappear.