EVAP System, Checking for Leaks
WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
Special tools, testers and auxiliary items required
- Smoke tester.
- EVAP and Fuel Supply System Vacuum hose and line routing diagram.
NOTE:
- Secure all hose connections using hose clamps appropriate for the model type
- Replace seals and gaskets when performing repair work.
Leak checking
- Using a Smoke tester, check the Evaporative Emission (EVAP) canister system for leaks.
NOTE:
- Always follow the manufacturers directions for the proper installation and operation of the Smoke tester being used.
If a leak is detected:
- Check the fuel filler cap seal for damage and for proper installation. Replace if necessary.
- Check the seals under the locking flanges and the union nuts are properly tightened on the fuel tank.
- Check all hose connections of the fuel supply system and replace or repair any leaking lines.
- Check all hose connections of the EVAP system and replace or repair any leaking lines.
- Repair or replace any damaged component.
If no leaks are found in the EVAP and Fuel Supply System:
- Erase the DTC memory if a DTC was set. Refer to → Diagnostic Mode 04 - Reset/Delete Diagnostic Data .
- Perform a road test to verify repair.
If a DTC was set and does not return:
Repair complete, Generate readiness code. Refer to → Readiness Code Description .
- End diagnosis.
If the DTC does return and no leaks are found in the EVAP and Fuel Supply System:
- Check the DTC memory for any DTC codes pertaining to the EVAP and Fuel Supply Systems. If a DTC is stored, perform the diagnostic test procedure for the suspected component. Refer to → Diagnostic Mode 03 - Interrogating Fault Memory .
End diagnosis.
If the DTC does return and no leaks are found in the EVAP and Fuel Supply System:
- Check the DTC memory for any DTC codes pertaining to the EVAP and Fuel Supply Systems. If a DTC is stored, perform the diagnostic test procedure for the suspected component. Refer to → Diagnostic Mode 03 - Interrogating Fault Memory .
End diagnosis.