Test sequence

WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 2006 Volkswagen GTI, 2005 Volkswagen Jetta, 2005 Volkswagen GTI, 2004 Volkswagen Jetta, and 2004 Volkswagen GTI. However, it is still accessible from the selected car via links, so may be relevant.

Pull 2-pin connector off After-Run coolant pump -V51- -arrow-.
Connect contacts of After-Run coolant pump -V51- to battery using aux. cables from V.A.G. 1594. After-run coolant pump must run.
If the after-run coolant pump does not run:

Fig 1: Connecting After-Run Coolant Pump To Battery
Courtesy of VOLKSWAGEN OF AMERICA, INC.
Replace After-Run coolant pump -V51-.
If the After-Run coolant pump -V51- runs:
Switch ignition off and on again.
Connect VAG 1527B voltage tester to disconnected connector for after-run coolant pump (V51) with auxiliary cable from V.A.G. 1594 A LED must light up.
NOTE: This check must be performed within 5 minutes after switching ignition off.

Fig 2: Connecting Voltage Tester To After-Run Coolant Pump
Courtesy of VOLKSWAGEN OF AMERICA, INC.

If the LED does not light up:
Locate and repair open circuit using wiring diagram.