Volkswagen Workshop Service and Repair Manuals > Polo Mk5 > Power unit | 4-cylinder diesel engine (1.6 l engine, common rail) | Fuel supply, gas operation | Testing low-pressure fuel systems (fuel pump) | Checking fuel pump, vehicles with 0.5 bar low-pressure fuel system | Checking voltage supply of fuel system pressurisation pump G 6

Checking voltage supply of fuel system pressurisation pump G 6

Checking voltage supply of fuel system pressurisation pump - G 6-

Special tools and workshop equipment required

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

t	Pickup clamp -V.A.G 1526B/2-

t	Test instrument adapter/DSO (5-pin) -VAS 5565-

Test prerequisites

l	Fuses must be OK.

l	The battery voltage must be at least 12 V, if necessary connect a battery charger.

l	All electrical consumers, e.g. lights and rear window heating, must be switched off.

–	Fold rear right seat bench forwards.

–	Remove cover from fuel delivery unit → Chapter.

–	Switch on ignition. The fuel pump must be heard to run for about 2 seconds.

–	Switch off ignition.

If the fuel pump does not start:

–	Pull connector off fuel delivery unit flange.

–	Connect test instrument adapter/DSO (5-pin) -VAS 5565- between connector and flange.

–	Connect hand-held multimeter -V.A.G 1526D- to contacts -1- and -5- of adapter.

–	Connect vehicle diagnostic tester and perform guided function „Fuel pump activation (Checking fuel pump)“.

Note

The fuel pump is now activated for 30 seconds.

–	Read voltage value on hand-held multimeter -V.A.G 1526D-: specification approx. battery voltage.

If no voltage is present:

–	Check activation of fuel pump relay and wiring for an open or short circuit → Vehicle diagnostic, testing and information system VAS 5051.

Voltage supply OK.

–	Remove fuel delivery unit → Chapter.

–	Check that electrical wiring between flange and fuel pump is connected and has continuity.

If no open circuit can be found:

–	Renew fuel delivery unit → Chapter.