Evaporative Emissions (EVAP) System Diagnostic Leak Test, Performing

Evaporative Emissions (EVAP) System Diagnostic Leak Test, Performing

Special tools, testers and auxiliary items required







- Vehicle Diagnostic, Testing and Information System VAS 5051 A with diagnostic cable VAS 5051/5A

NOTE:
- Secure all hose connections using hose clamps appropriate for the model type Parts catalog.
- 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.
- Electrical consumers switched off (Radiator fan must not run during test).
- Climate control switched off.







- Vehicle Diagnostic, Testing and Information System VAS 5051 A connected, On-board diagnostics and vehicle system "01 Engine electronics" selected.
- No faults in DTC memory.
- Intake air temperature less than 90 degrees C - Measuring value block 004, display field 4.
- Coolant temperature less than 95 degrees C - Measuring value block 004, display field 3.
- Throttle valve angle less than 10 degrees - Measuring value block 003, display field 3.







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







Display on VAS 5051 A:
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 A:
- 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 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 A display in display field - 4- -:

- In case of malfunction: Syst. n.O.K..

- Check readings of the 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.
- Afterwards, perform the leak diagnosis again.