Checking voltage supply and current draw of fuel system pressurisation pump G6 - vehicles with supplementary fuel pump V393 — VW

Checking voltage supply and current draw of
fuel system pressurisation pump
G6
- vehicles with
supplementary fuel pump
V393
Special tools and workshop equipment required
Pickup clamp
V.A.G 1526B/2
Hand-held multimeter
V.A.G 1526D
Vehicle diagnosis, testing and information system
VAS 5051B
Test instrument adapter/DSO (5-pin)
VAS 5565
Test prerequisites
Fuses must be OK.
The battery voltage must be at least 12 V, if necessary connect a battery charger.
All electrical consumers, e.g. lights and rear window heating, must be switched off.
Checking function and voltage supply
Separate electrical connector
5
to
supplementary fuel pump
V393
in vicinity of fuel filter.
Raise vehicle.
Switch on ignition (2nd mechanic). The fuel pump must be heard to run for about 2 seconds.
Note
To check the voltage, the engine has to be started or the delivery unit has to be actuated via the tester.
All vehicles (continued)
If fuel pump does not start, lower fuel tank
Chapter
.
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 carry out guided function
“Check electrical fuel pump(s)”
.
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 tester
.
Voltage supply OK:
Remove fuel delivery unit
Chapter
.
Check that the electrical lines between flange and fuel pump are connected and have continuity.
If no open circuit can be found:
Renew fuel delivery unit
Chapter
.
Checking current draw of fuel pump
Special tools and workshop equipment required
Pickup clamp
V.A.G 1526B/2
Hand-held multimeter
V.A.G 1526D
Vehicle diagnosis, testing and information system
VAS 5051B
Test instrument adapter/DSO (5-pin)
VAS 5565
Note
The battery voltage and the diesel fuel temperature have a great influence on the current draw of the fuel pump. For this reason make sure that the battery voltage is at least 12 V whilst checking and the diesel fuel temperature does not fall to the freezing point.
Test prerequisites
Battery voltage at least 12 V
Diesel fuel temperature above 10°C
Checking current draw
If fuel pump does not start, lower fuel tank
Chapter
.
Release connector
arrow
and pull off from flange
1
.
Connect
test instrument adapter/DSO (5-pin)
VAS 5565
to connector and fuel delivery unit.
Connect pick-up clamp
A
to red terminal with lettering
“pick-up clamp”
for
test instrument adapter/DSO (5-pin)
VAS 5565
.
Note
Pickup clamp of
hand-held multimeter
V.A.G 1715
can also be connected to red terminal with lettering
“pickup clamp”
of
test instrument adapter/DSO (5-pin)
VAS 5565
.
Separate electrical connector
5
to
supplementary fuel pump
V393
in vicinity of fuel filter.
Switch ignition on.
Connect
vehicle diagnostic tester
, and carry out guided function
“Check electrical fuel pump(s)”
.
Note
The fuel pump is now activated for 30 seconds.
Read current draw on
hand-held multimeter
V.A.G 1526D
. Specification: max. 7.5 amps.
If the measured value is not within specifications:
Renew fuel delivery unit
Chapter
.