Audi Workshop Service and Repair Manuals

Removing and installing fuel pump control unit -J538- Special tools and workshop equipment required

t  Union nut tool -T40068 A- Removing –  Observe safety precautions → Chapter. –  Observe rules for cleanliness → Chapter.   WARNING Large amounts of fuel can escape. The fuel tank must not be more than 1/4 full when removing the fuel pump control unit -J538-, otherwise a large amount of fuel will escape. –  Drain fuel tank if necessary → Chapter. –  Move passenger's seat as far to front as possible (if necessary).   Caution To prevent irreparable damage to the electronic components when disconnecting the battery: Observe notes on procedure for disconnecting the battery. –  Disconnect battery → Electrical system; Rep. gr.27.

–  Remove rear seat bench → Rep. gr.72. –  Unscrew cover for flange -arrows-.

–  Unplug electrical connector -1- on flange. –  If fitted, unplug electrical connector -2- for metering pump for auxiliary heater on flange.

WARNING Risk of injury - fuel system operates under high pressure. To reduce the pressure in the fuel system, wrap a clean cloth around the connection and carefully loosen the connection. –  Press release tab and disconnect fuel line -2- at flange. –  Press release tab and disconnect fuel line -1- (if fitted) leading to metering pump for auxiliary heater at flange.

WARNING Large amounts of fuel can escape. The fuel tank must not be more than 1/4 full when removing the flange, otherwise a large amount of fuel will escape. –  Unscrew union nut using union nut tool -T40068 A--arrow-.   Note The plastic detent on the threaded ring will break off when the union nut is unscrewed - this can be disregarded.

–  Cover opening of fuel tank with clean cardboard -1- to prevent dirt particles from falling into the tank. –  Remove bolts -arrows-.

–  Guide out fuel pump control unit -J538--item 1- towards interior between fuel tank and underbody. –  Unplug electrical connector and remove fuel pump control unit. Installing l  Tightening torque → Chapter Installation is carried out in the reverse order; note the following:   Note Renew seal and union nut. –  Bring fuel pump control unit -J538- into installation position and secure with bolts.

–  Slip union nut -1- over your left arm and press flange -2- firmly into installation position -arrow- with your left hand. l  Lug -4- on flange must be between tabs -3- and -5- on threaded ring.

–  Take union nut -1- off your left arm with your right hand and at the same time keep pressing down flange -2- firmly with your left hand -arrow-. –  Position union nut -1- with your right hand in such a way that double ridge -5- on ribs aligns with lug -3- of flange (approx. „ten o'clock position“). This will make union nut engage immediately with beginning of thread -4- when tightening.

–  Keep pressing flange downwards firmly -arrow-. –  Turn union nut approx. 480° with your right hand until double ridge -1- is in approx. „two o'clock position“ and at the same time keep on pressing flange downwards firmly with your left hand.

Caution Take care to avoid leakage at flange. Press flange downwards firmly when tightening union nut to make sure flange does not also turn. –  Tighten union nut for flange using union nut tool -T40068 A-.

l  Checking: Double ridge -1- must now be aligned between „seven o'clock and eight o'clock position“.

–  Connect fuel lines -1- and -2-. –  Connect electrical connectors. –  Install cover for flange → Fig.. –  Install rear seat bench → Rep. gr.72. –  Connect battery (observe notes on procedure for connecting the battery → Electrical system; Rep. gr.27). –  Vehicles with auxiliary heater: Bleed fuel supply line leading to metering pump → Chapter.