Audi Workshop Service and Repair Manuals

Note:

→ The fuel pump relay is located in central electrics in left hand footwell, relay position 4.

A - Testing fuel pump relay -J17

• ‒ Remove storage compartment from front left hand footwell.

• ‒ → Remove fuel pump fuse from fuse holder and connect diode test lamp V.A.G 1527 between earth and one of the two contacts of fuel pump fuse.

=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations

• ‒ Operate the starter briefly.

The fuel pump relay should pick up (can be felt and heard) and the diode test lamp should light up.

• ‒ If the fuel pump relay does not respond, test activation .

• ‒ If the fuel pump relay responds but the diode test lamp does not light up, repeat the test on the other contact of the fuse holder.

• ‒ → If the diode test lamp still does not light up, test wiring between contact 23 in relay position 4 and fuel pump fuse for continuity and if necessary, rectify open circuit.

=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations

• ‒ If the power supply, activation and wiring for the fuel pump relay are OK, fit a new fuel pump relay.

B - Testing power supply and activation of fuel pump relay

Note:

Activation of the fuel pump relay can also be tested using the final control diagnosis.

=>Page01-72.

• ‒ Remove fuel pump relay -J17 from central electrics, relay position 4.

Checking power supply

• ‒ Switch the ignition on.

• ‒ → Connect hand-held multimeter V.A.G 1526 first between contact 19 of relay panel and earth and then between contact 17 of relay panel and earth (each permanent positive; terminal 30 from battery).

Specification: approx. battery voltage in each case

• ‒ If the values are not as specified, rectify the open circuit.

=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations

Checking actuation

• ‒ → Connect diode test lamp V.A.G 1527 to contact 16 of relay panel (earth activation from engine control unit) and positive.
• ‒ Operate the starter briefly.
• ‒ The diode test lamp should light up and remain lit when the starter is operated.

Note:

Diode test lamps with a low current consumption do not go out completely but continue to glow faintly until the starter is operated.

• ‒ If the activation, wiring and power supply for the fuel pump relay are OK but the fuel pump relay still does not respond, fit a new fuel pump relay.

If the diode test lamp does not light up, test the wiring as follows:

• ‒ Connect the V.A.G 1598/31 test box to wiring harness leading to engine control unit; the engine control unit must not be connected
  => Page 24-23.

• ‒ Connect hand-held multimeter between contact 16 on relay panel and socket 65 on the test box, then test wiring for open circuits.
• ‒ Rectify open circuit if necessary.

=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations

• ‒ If there is no open circuit and the diode test lamp still does not light up, fit a new engine control unit
  => Page 24-30.
• ‒ Refit the fuel pump fuse.