Audi Workshop Service and Repair Manuals

Checking fuel pump (electrical test)

Special tools and workshop equipment required

t	Union nut tool -3217-

t	Adapter cable -V.A.G 1348/3-2-

t	Remote control for V.A.G 1348 -V.A.G 1348/3A-

t	Hand-held multimeter -V.A.G 1526D-

t	Auxiliary measuring set -V.A.G 1594C-

Procedure Observe test conditions → Chapter. –  Open lid of fuse box at left side of instrument panel. –  Pull fuse No. 28 off fuse holder (left row, 5th large fuse from the top). –  Connect remote control -V.A.G 1348/3A- for V.A.G 1348 with adapter cable -V.A.G 1348/3-2- to right-hand terminal on fuse socket no. 28 -arrow-. –  Connect crocodile clamp to vehicle battery (+). –  Press remote control switch. l  Pump should start running audibly.   Note The fuel pump runs very quietly. Where possible, avoid noisy surroundings for this test.

If no noise can be heard from pump: –  Unbolt cover (right-side) underneath rear seat bench. –  Unplug electrical connector -arrow-.

–  Connect multimeter (voltage test range) between contacts -1- and -4-. –  Press remote control switch. l  Specification: approx. battery voltage If specification is not obtained: –  Locate and eliminate open circuit using current flow diagram → Current flow diagrams, Electrical fault finding and Fitting locations. If reading matches specification although no noise can be heard from pump:   Caution To prevent damage to the electronic components when disconnecting the battery: Observe notes on procedure for disconnecting the battery. –  Disconnect battery → Rep. Gr.27. l  The fuel tank must not be more than 3/4 full when removing the flange. Drain the tank if necessary. Procedure → Chapter.   Caution To prevent damage to the electronic components when disconnecting the battery: Observe notes on procedure for disconnecting the battery. –  Disconnect battery → Rep. Gr.27.

–  Unbolt cover (right-side) underneath rear seat bench. –  Unplug electrical connector -arrow-.   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 tabs and disconnect fuel supply pipe -1- and fuel return pipe -2-.

Caution The fuel tank must not be more than 3/4 full when removing the fuel delivery unit. Otherwise a large amount of fuel will escape. –  Unscrew union nut using union nut tool -3217-. –  Take flange of fuel delivery unit out of opening in fuel tank and move clear, leaving hoses connected. –  Check that wiring between flange and fuel pump is connected and test for continuity. If no wiring fault is detected: fuel pump is defective. –  Renew fuel delivery unit → Chapter.