Yes, diagnostics has to be used to bleed the fuel system after the filter change.
Diesel Fuel Filter Top Cover bolts around the fuel piping is loosened in the order shown.
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Between position 1 & 3 in the above photo, you will see a raised section of the top cover. Use a flat bladed screw driver in the slot and twist to gently force the cover upwards.
When the cover is off, remove the old rubber O ring seal that is sitting around the inner lip of the Fuel Filter Top Cover.
Take out the old Fuel Filter out of the lower cannister part of the Filter Housing and dispose of. Insert the replacement Filter. (No water drainage is performed). [Diesel Fuel Filter change interval is 90,000Km (55,000 miles), non E590 standard fuel is 30,000Km]
Moisten the new Filter Top Cover Seal and carefully fit to the Top Cover.
Re-fit the Top Cover into the Fuel Filter housing and press evenly and firmly into the Lower Filter Housing.
Do not tighten the 5 Top Cover securing bolts unitl the Filter Top Cover is correctly seated in its final intended position otherwise tightening the bolts could cause damage to the seal and Top Cover.
Re-fit the 5 Filter Top Cover bolts by hand tightening first and tighten in the sequence shown in the photo above to the torque shown.
Now the system needs to be bled and checked. You will need VCDS to complete this.
Turn on the ignition but do not turn or start the engine.
Switch on VCDS and open the Engine ECU Controller 01 screen.
In VCDS select "Basic Settings", enter Group's first field as 035 and press "Go!" to force it to activate. The Fuel System Pumps should run for 60 seconds. Do this 3 times so the fuel system has been pumped for a total of 3 minutes.
(Check this happens before dis-assembling the Fuel Filter as Engine ECU software will not always run the Fuel Pumps using Basic Settings Group 034)
Exit VCDS as a program, leave the PC running.
Now start the engine and allow to idle fo about 2 minutes. Switch off the negine. Check the Fuel Filter area for any fuel leaks.
If all is well switch on the ignition, restart VCDS and look at the Engine ECU Controller 01 Fault Codes. Erase any code that are apparent.
Tidy up and take the Scirocco for a short drive, taking VCDS with you. After about 10 mins, stop and check the Engine ECU Controller memory for Fault Codes. Hopefully its clear. If not, clear the codes down again and drive a further 10 mins and recheck.
That should be it with one final fault memory check to make sure there are no stored fault codes which would revert the engine ECU into "Emergency Running" mode.
Do a final leak check inspection of the Fuel Filter housing.
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There is an alternative method for priming but you will still need VCDS to clear do Fault Codes in the Engine ECU Controller 01 fault memory to prevent the engine ECU reverting into "Emergency Running" mode.
All the same method as above but for the blue text, do this instead.
Under the Engine Top Cover - left front area, disconnect the electrical connector to the Fuel Pressure Regulating Valve to STOP the engine starting.
Now, crank only, the engine on the starter for a period of 13 seconds and then stop for 20 seconds to prevent the battery/starter overheating. Repeat twice more the cranking for 13 seconds followed by a 20 second pause before cranking a third time.
Check the Filter Housing for leaks. Refit the the Fuel Pressure Regulating Valve electrical connection. Refit the Engine Top Cover.
Turn the ignition on. Start VCDS and clear the fault codes in Engine ECU Controller 01.
Exit VCDS as a program, leave the PC running.
C.