Leak Detection Test, Performing

Leak Detection Test, Performing

Special tools, testers and auxiliary items required

• Vehicle Diagnostic, Testing, and Information System (VAS 5051B)

Observe safety precautions. Refer to => [ Safety Precautions ] Fuel Supply System.

Observe rules for cleanliness. Refer to => [ Clean Working Conditions ] Fuel Supply System.

• Secure all hose connections using hose clamps appropriate for the model type.

• Replace O-rings and gaskets when performing repair work.

Procedure

• Parking brake is applied.

• Manual Transmission Shift lever in neutral.

• Vehicles with automatic transmission: Selector lever in "P" or " N".

• Engine running at idle speed or with brakes actuated and accelerator fully depressed (elevated engine RPM).

• Electrical consumers switched off (Radiator fan must not run during test).

• Air conditioning system switched off.

• Vehicle Diagnosis, Testing and Information System ( VAS 5051B) connected.





• No faults in DTC memory.

• Intake air temperature less than 90 °C => Measuring value block 004, display field 4.

• Coolant temperature less than 95 °C => Measuring value block 004, display field 3.

Display on (VAS 5051B):





- Tap "On Board Diagnostic" in selection - 1 - and activate by tapping the -> button.

Display on (VAS 5051B):





- Tap "01 - Engine Electronics" vehicle system in selection - 1 - and activate by tapping the -> button.

Display on (VAS 5051B):





- Tap diagnostic function "006 - Basic Setting" in selection - 1 - and activate by pressing the -> button.

Display on (VAS 5051B):





- In button field - 1 -, press buttons 7 1 for "display group 071" and confirm entry by pressing Q button.

Display on (VAS 5051B):





- Check reading in display field - 1 -.

• Specified value: "Reed closed".

• If "Reed closed" is displayed, continue test.

• If the reading on the display shows "Reed open": Briefly open the cap of the fuel tank to relieve pressure - thereby the reed contact will close again.

- Activate basic setting by pressing Activate button - A -.





Display on (VAS 5051B):

- Check reading in display field - 4 -.

• Specified value: "Test ON".

The system test takes several minutes.

- Check reading in display field - 4 -.

• Specified value: "Syst.O.K.".

The system is sealed, the test is ended.

- End function "006 - Basic setting" by pressing <- button.

Fault indication

If a malfunction was recognized during the system test, the malfunction is indicated afterward.

On (VAS 5051B) display in display field - 4- -:





• In case of malfunction: Syst. not O.K..

- Check readings of the diagnosis in display field - 2 -.

• "Small leak" or "Large leak".

- End function "006 - Basic setting" by pressing <- button.

If the system has recognized a small or large leak:

- Check fuel supply and tank ventilation systems for leaks. Refer to => [ Checking Fuel Supply and Tank Ventilation Systems for Leaks ] Checking Fuel Supply and Tank Ventilation Systems for Leaks.

- Afterwards, perform the leak diagnosis again.