Fuel Tank Leak Detection Control Module, Testing For Internal Leaks

CAUTION:

Clamp only soft rubber lines when isolating a leak. To avoid risk of damage, never clamp hard plastic lines!

-- Clamp off fuel tank leak detection control module outlet (filter side) using Hose Clamps Up to 25 mm Dia.:VAS3094 or equivalent by removing the filter connection and plugging the port on the fuel tank leak detection control module tightly with a soft rubber plug.

NOTE:

Vehicles equipped with the fuel tank leak detection control module may require one of two different test adapters that may vary depending on the model.

-- Attach Evaporative Emissions Tester - Adapter 57:KLI9210/57 or T adapter between the EVAP system and the EVAP Canister Purge Regulator Valve 1 -N80-.

NOTE:

No special tool T adapter is available at this time. The T adapter may have to be fabricated if it is required for testing.

-- Attach the test hose from the Evaporative Emissions Tester:KLI9210 to the adapter.

NOTE:

Make sure tester is calibrated to 10 inches of water. Refer to EVAP SYSTEM, TESTING .

-- Set control valve -2- from "Hold" to "Test".

Fig 1: Connect Vehicle Interface Hose To Self-Test Port

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Calibrate Evaporative Emissions Tester:KLI9210 to 10 in. of water prior to connecting the to the vehicle.

-- Increase the current pressure until it reaches 10 in. H₂ O (25 mbar).

-- Monitor the pressure gauge -3- and the flow meter -4-. Allow the flow rate to decrease. If pressure builds to 10 in. H₂ O (25 mbar), the fuel system is full.

NOTE:

Depending on the level of fuel in the tank, it may take up to three minutes to notice a visible decrease in flow rate.

If any flow is shown on meter, a leak is present in the system. Locate the leak.
If no flow is shown on the meter, proceed to the following steps.

-- After the pressure has stabilized, set control valve -2- to "Hold".

-- After five minutes, the pressure must not drop below 8 in. H₂ O (20 mbar).

If pressure drops below 8 in. of water in five minutes then find leak with the smoke tester, soapy water and/or isolating components by clamping them off individually.

If fuel system pressurization does not stabilize:

-- Verify all fuel system outlets have been sealed before continuing.

NOTE:

Any flow shown on flow meter indicates a leak.

If flow meter on tester registers flow near or above preset pressure:

CAUTION:

Clamp only soft rubber lines when isolating a leak. To avoid risk of damage, never clamp hard plastic lines!

-- Clamp off hose -arrow- leading from EVAP Canister Purge Regulator Valve 1 -N80- to intake manifold.

If no flow is present and the pressure drop is above 8 in. of water after five minutes:

-- Replace fuel tank leak detection control module and repeat test.

If meter indicates no flow after test:

-- Perform quality check and return vehicle to customer.