Diagnostic Leak Test, Performing

Diagnostic Leak Test, Performing

Special tools, testers and auxiliary items required







- Vehicle Diagnostic, Testing and Information System VAS 5051 with diagnostic cable VAS 5051/5A (VAS 5051 B version shown as example only)

Observe safety precautions.
Observe rules for cleanliness.

NOTE:
- Secure all hose connections using hose clamps appropriate for the model type.
- Replace O-rings and gaskets when performing repair work.

Test conditions
- Parking brake is applied.
- Vehicles with manual transmission: Shift lever in neutral.
- Vehicles with automatic transmission: Selector lever in position "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 Diagnostic, Testing and Information System VAS 5051 connected, On-board diagnostics and Data Link Connector DLC "01 Engine electronics" selected.
- No DTCs in DTC memory.
- Intake air temperature less than 90 degrees C. See Measuring value block 004, display field 4.
- Coolant temperature less than 95 degrees C. See Measuring value block 004, display field 3.
- Throttle valve angle less than 10 degrees C.See Measuring value block 003, display field 3.

Test sequence







Display on VAS 5051 :
- In selection - 1 - , click on diagnostic function "04 - Basic Setting".







Display on VAS 5051 :
1 - Enter display group
- Select function "071" in button field - 2 - for "display group number 071" and press Q to confirm input.







Display on VAS 5051 :
- Check reading in display field - 1 -.
- Specification: "Reed closed."

NOTE:
- 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 - .
- Check reading in display field - 4 - .
- Specification: "Test ON"

The system test takes several minutes.
- Check reading in display field - 4 - .
- Specification: "Syst.O.K."

The system is sealed, the test is ended.
- End function "04 - Basic setting" by pressing <- button.

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







On VAS 5051 display in display field - 4- - :
- In case of malfunction: Syst. n.O.K..
- Check readings of diagnosis in display field - 2 - .
- "Small leak" or "Large leak"
- End function "04 - Basic setting" by pressing <- button.

If the system has recognized a small or large leak:
- Check fuel supply and tank ventilation systems for leaks. Testing and Inspection
- Afterwards, perform the leak diagnosis again.