Current Draw, Checking
Test Conditions
- The battery voltage must be at least 12 volts.
- The fuses must be OK.
- All electrical consumers such as, for example, lights and rear window defogger, must be turned off.
- Fuel temperature inside the fuel tank above 10 °C (50 °F).
The battery voltage and the temperature of the diesel fuel strongly influence the current draw of the fuel pump. Make sure the battery voltage is at least 12 volts and the temperature of the diesel fuel inside the fuel tank is not at the freezing point.
Test Sequence
-- Remove the rear seat bench. Refer to Removal and Installation .
-- Remove the cover -1- for the fuel delivery unit. The arrow -2- points in direction of travel.
-- Disconnect the connector -1- from the fuel delivery unit flange.
-- Connect the test instrument adapter/DSO (5-pin) VAS 5565 between the connectors on the flange and cover.
-- Connect the current clamp -A- to the red wire on test instrument adapter/DSO (5-pin) VAS 5565 with the word "current clamp" on it.
The current clamp from the multi-meter V.A.G 1715 can also be connected to the red wire on test instrument adapter/DSO (5-pin) VAS 5565 with the word "current clamp" on it.
-- Connect the multi-meter V.A.G 1526 D to the current pickup V.A.G 1526 B/2.
-- Disconnect the connector -1- from the auxiliary fuel pump -V393- (inside the engine compartment on the right side).
-- Connect the vehicle diagnostic tester -1- as follows:
-- Connect the diagnostic cable -2- to the Data Link Connector (DLC) in the driver's foot well.
-- Turn on the ignition.
-- Perform the guided function "Check Electric Fuel Pumps".
The fuel pump now runs for 60 seconds.
-- Read the current draw on the multi-meter V.A.G 1715.
Specified Value
- Minimum 5.5 amps
- Maximum 7.5 amps.
-- Turn off the ignition.
If the current draw is below the specified value:
-- The fuel pump is faulty, replace the fuel delivery unit. Refer to FUEL DELIVERY UNIT .