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Home >> Audi >> 2013 >> S7 >> Repair and Diagnosis (Single Page) >> Engine Performance >> Engine Control Systems >> 4.0L - Generic Scan Tool - Engine Code(S): CEUC & CRDB (Transmission DTC Table & Diagnostic Procedures) >> St Generic Scan Tool >> Diagnosis And Testing >> Diagnostic Procedures >> Fuel Tank Leak Detection Control Module -J909- & INTEGRATED Fuel Tank Pressure Sensor -G400-, CHECKING >> Function
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Fuel Tank Leak Detection Control Module -J909- & INTEGRATED Fuel Tank Pressure Sensor -G400-, CHECKING: Function

The system can test the evaporative system integrity by applying a vacuum signal, ported or manifold, to the fuel tank in order to create a small vacuum. The Engine Control Module -J623- then monitors the ability of the system to maintain the vacuum through signals sent from the Fuel Tank Pressure Sensor -G400- / Fuel Tank Leak Detection Control Module -J909-. If the vacuum remains for a specified period of time, then there are no evaporative leaks, and a PASS is reported by the Engine Control Module -J623-. If there is a leak, the system either will not achieve a vacuum, or a vacuum cannot be maintained. Usually a fault can only be detected after a cold start.

Special tools and workshop equipment required