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Checking fuel pressure > < Checking fuel pump

Polo Mk5

Checking function and voltage supply
Checking function and voltage supply
Test prerequisites
l  Fuel pump fuse must be OK. Fuse assignment → Current flow diagrams, Electrical fault finding and Fitting locations
l  The battery voltage must be at least 11.5 V.
  Note
t  Function of fuel pump is checked using final control diagnosis.
t  Observe the functional description of the crash fuel shut-off → Chapter.
   
–  Connect Vehicle diagnosis, testing and information system -VAS 5051 A- as follows:
–  Push diagnosis cable connector onto diagnosis connection in driver footwell.
–  Switch on ignition.
–  Press buttons on display one after the other for „Vehicle self-diagnosis“, „01 - Engine electronics“ and „Final control diagnosis“.
–  Press right arrow button on display up to final control diagnosis for fuel pump electronics.
The fuel pump must now run slowly up to maximum speed.
  Note
The fuel pump runs very quietly.
Switch off ignition.
If fuel pump does not run:
–  Fold rear seat forwards.
  N01-0590
–  Remove cover -1- from fuel delivery unit.
–  First check that the connector is fitted securely by pulling the connector without pressing the catch.
  N20-10621
–  Pull connector off fuel delivery unit flange.
–  Check the contacts on the connector and on the fuel delivery unit for damage.
  N20-10622
–  Connect test instrument adapter/DSO (5-pin) -VAS 5565- to connector and fuel delivery unit.
–  Connect voltage tester -V.A.G 1527B- to wires -1- and -5- of adapter.
Switch on ignition.
–  LED must light up briefly.
If LED does not light up:
–  Locate and eliminate open circuit referring to current flow diagram: → Current flow diagrams, Electrical fault finding and Fitting locations.
If LED lights up (voltage supply OK):
  N20-10423
–  Unscrew union nut with union nut tool -3217-.
–  Check that electrical wires between flange and fuel pump are connected.
If no open circuit can be found:
–  Renew fuel delivery unit.
  A20-0106

Checking fuel pressure > < Checking fuel pump