Residual Pressure in Fuel Delivery Unit, Checking:
Check for the leak on the fuel tank side. Proceed as follows:
-- Remove the bench seat. Refer to REAR SEATS .
-- Remove the carpet and fold it upward.
-- If equipped, remove the Fuel Pump Control Module -J538- -2- from the right cover.
-- Unclip the right cover -1- at the tabs in direction of -arrows- using the :3409 .
-- Disconnect the fuel line -2-. Disconnect the connector couplings. Refer to CONNECTOR COUPLINGS, DISCONNECTING .
-- Connect the :VAS6550 to the fuel delivery unit -1- with the :VAS6550/2 .
-- Connect the :VAS6550/1 between the :VAS6550 and the fuel supply line -2-.
-- Pull on the connector couplings to check them for secure fit.
-- Make sure that the drain -C- is closed and that the shut-off valves -A and B- on the :VAS6550 -1- are open.
-- Activate the fuel pump using the output diagnostic test mode to build the fuel pressure.
-- Close the shut-off valve -B- on the pressure gauge immediately after the pressure has been reached. The lever is perpendicular to the flow direction.
-- Repeat the residual pressure check. Refer to FUEL PRESSURE, CHECKING .
If the Pressure No Longer Decreases:
-- Check the fuel lines between the engine and the fuel tank for leaks.
If the Pressure Drops Again:
-- Open the locking ring using the :T10202 .
-- Do not bend the :T10202 and push hard on the locking ring. If the wrench slides down, the fuel delivery unit can be damaged.
-- Check if all hose connections on the fuel delivery unit and flange are connected.
If no error can be found:
The pressure relief valve in the fuel delivery unit flange or the pressure retention valve in the fuel pump leaks.
-- Replace the flange with the fuel filter and then repeat the pressure retention test. Refer to FUEL PRESSURE, CHECKING .
If the pressure drops again:
-- Replace the fuel delivery unit. Refer to FUEL DELIVERY UNIT/FUEL LEVEL SENSOR, REMOVING AND INSTALLING .