Checking Fuel Tank And Tank Venting System For Leaks

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


NOTE:
An OBD fault is indicated by the "Check Engine" indicator lamp in the instrument cluster lighting 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%
- Reserve indicator lamp "off"
- Leave car in workshop for at least 2 hours so that fuel temperature comes into line with workshop temperature (ideal fuel temperature approx. 10...20°C).
- Do not under any circumstances fill up car with fresh fuel (strong exhalation of 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.

By selecting:
- Complete vehicle
- Drive
- Engine management MS43
- Tank system test
- Diagnosis module tank leakage (DM-TL)
adopt test module in test schedule. Switch to the test schedule and implement the tank leakage diagnosis module. Leakage test is carried out. If fault is recorded again in DME fault memory (tank leak detected), carry out leak test.