Leak Check

EVAP Canister, Checking

Special tools and equipment
- V.A.G 1551 Scan Tool or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Checking conditions







- Fuse 29 must be OK.
- No codes stored in DTC memory
- All electrical consumers, e.g. lights and rear window defogger must be switched off
- Air conditioner must be switched off.
- Intake air temperature less than 90 °C See display group 04, display field 4
- Coolant temperature less than 95 °C See display group 04, display field 3

Checking for leaks
If a small or large leak is detected during the check of the EVAP system, proceed as follows.
- Switch ignition off.
- Pull hose from Leak Detection Pump (LDP) off EVAP canister and seal it.
- Repeat functional check.

If the malfunction is still present:
- Remove rear right wheel housing liner.
- Check connecting lines and hoses between LDP and EVAP canister.

If the malfunction is still present:
- Check whether fuel filler cap is fully closed or if seal is faulty, replace if necessary.
- Check whether locking ring for fuel delivery unit is tight (found under luggage compartment floor trim). Replace seal if faulty.
- Tighten locking ring with special tool 3217.
- Check supply and return lines on fuel delivery unit for leaks.
- Remove EVAP from spare wheel well and check for cracks and leaks, replace if necessary.
- Check connecting lines and hoses between EVAP canister and fuel tank flap unit/EVAP canister purge regulator valve 1.
- Check that hoses and hose clamps are tight.
- Repeat functional check.