Checking power supply

WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, and 2003 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Requirements

Fuse for wastegate bypass regulator valve OK → Electrical Wiring Diagrams, Troubleshooting and Component Locations
Fuel pump relay OK → 24 - MULTIPORT FUEL INJECTION (MFI)

Fig 1: Identifying 2-Pin Electrical Connector & Terminals

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Connect voltage tester VAG1527B as follows:

Connector contact	Measure to
1	Engine Ground

Briefly operate starter.

LED must light up

If LED does not light up:

Check for open circuit in wiring from contact 1 of connector through fuse to fuel pump relay: → Electrical Wiring Diagrams, Troubleshooting and Component Locations
If necessary, eliminate open circuit.

If LED lights up:

Check actuation.