why does my Volkswagen Tiguan's engine light stay on after I fill the gas tank?

Solution

1. Preparation

• Gather all necessary tools and parts before starting the repair.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the negative terminal of the battery for safety.

2. Inspect and Replace Gas Cap

• Sub-steps:
  1. Remove the gas cap and inspect the rubber seal for cracks or wear.
  2. If damaged, replace the gas cap with a new one that meets OEM specifications.
  3. Reinstall the gas cap securely and ensure it clicks into place.

3. Check and Repair EVAP System

• Sub-steps:
  1. Locate and inspect the EVAP canister and purge valve for any visible damage or blockage.
  2. If the purge valve is faulty, disconnect the electrical connector and remove it using a socket set.
  3. Replace the purge valve with a new component and reconnect the electrical connector.
  4. Inspect the charcoal canister for signs of damage or saturation; replace if necessary.

4. Clear Error Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear any existing error codes.
  3. Start the engine and observe if the check engine light reappears.