Fuel System, Checking For Leaks

Leak Detection System 

• The function of the leak detection system is based on the premise that the fuel systems creates a natural vacuum when the fuel in the fuel tank becomes colder.
• For the leak detection the temperature and pressure measuring devices are needed. The Fuel Tank Leak Detection Control Module -J909- item -2- with an integrated Fuel Tank Pressure Sensor -G400- located on the EVAP canister -7- supplies these values.
• The system is considered to be closed when the measured vacuum is 2.5 mbar (1.87 mmHg) as the fuel tank temperature drops.
• There is a leak in the fuel system if there is not vacuum, which will result as an entry in the control module DTC memory.

1 - Signal wire to the Engine Control Module -J623-

3 - Bleed line to the engine

4 - Fuel tank

5 - Fuel tank vent line

6 - Air filter vent line