Fuel Pump, Checking
Special tools and workshop equipment required
- Voltage tester V.A.G 1527 B
- Connector test set V.A.G 1594C
- Vehicle diagnosis, testing, and information system VAS 5051B
Test Conditions
- The fuses must be OK.
- The battery voltage must be at least 11.5 Volts.
- All electrical consumers like, for example, lights and rear window heating, must be switched off.
Function and Voltage Supply, Checking
-- Switch ignition on.
- Fuel Pump (FP) must briefly start up audibly.
Fuel Pump (FP) runs quietly.
-- Switch off ignition.
If Fuel Pump (FP) Does Not Start Up
-- Remove seat bench Removal and Installation .
-- Unclip cover -1- from fuel delivery unit. Arrow -2- points in direction of travel.
-- Disconnect the connector -1-.
-- Connect voltage tester V.A.G 1527 B using adapter cables from connector test kit V.A.G 1594C to outer terminals of connector.
-- Switch ignition on.
- LED must light up briefly.
If LED does not light up briefly:
-- Locate and repair open circuit in wiring.
LED lights up briefly (voltage supply OK):
-- Fuel delivery unit, removing FUEL DELIVERY UNIT .
-- Check if the electrical wiring between the flange and fuel pump is connected and has continuity.
If no open circuits are found:
-- Replace fuel delivery unit FUEL DELIVERY UNIT .
Fuel Pump Current Draw, Checking
-- Remove seat bench Removal and Installation .
-- Unclip cover -1- from fuel delivery unit. Arrow -2- points in direction of travel.
-- Connect current probe -A- of vehicle diagnosis, testing and information system VAS 5051B on cable -B- to terminal 1 of 5-pin harness connector.
-- Start the engine and run at idle speed.
-- Measure Fuel Pump (FP) current draw:
- Specified value: max. 7.5 amps.
-- If the measured value is greater than the specified value:
-- Replace fuel delivery unit FUEL DELIVERY UNIT .