Checking Tank Venting /Tank Leakage Diagnosis Module (DM-Tl)

Checking Fuel Tank And Tank Venting System For Leaks With Tank Leakage Diagnosis Module (DM-TL)


NOTE: An OBD fault is indicated when the "Check Engine" indicator lamp in the instrument cluster lights up. This may indicate a leak in the tank venting system. Information on this is provided by the fault memory of the DME control unit.


- Read out fault memory of DME control unit and carry out a diagnosis in accordance with faults stored.
- A leak test with the DM-TL module is then carried out if:
- The components of the DM-TL module are O.K.
- A error is stored in the DME fault memory (tank leak detected).

Adhere to following conditions in order to carry out a correct leak test:
- Content of fuel tank < 90%
- Low-fuel indicator lamp "off"
- Park the car in the workshop at least 2 hours before the test so that the fuel temperature is approximately that of the workshop temperature (ideal fuel temperature approx. 10...20 °C).
- Never refuel the vehicle directly prior to the leak test due to the strong emission of gas by the fresh fuel.
- Check that tank cap is correctly seated.



WARNING!
During the leak test, under no circumstance apply external pressurization through the tank filler neck as this may cause incorrect readings.


Clear DME fault memory.
Select "Service functions" function on Diagnosis and Information System (DIS).
Select DM-TL tank leak system check from "DME system check" menu, leak test is carried out.
If a fault is stored again in DME fault memory (tank leak detected), carry out leak testing.