Checking fuel pump relay J17 and activation — AUDI

Checking
fuel pump relay
J17
and activation
Special tools and workshop equipment required
Hand-held multimeter
V.A.G 1526 A
or
V.A.G 1526 B
Adapter set
V.A.G 1594 A
or
V.A.G 1594 C
Adapter cable, 121-pin
V.A.G 1598/31
(test box)
Vehicle diagnostic, testing and information system
VAS 5051 A
with
diagnosis lead
VAS 5051 A/1
Function
The fuel pump and some of the injection system components are powered via the
fuel pump relay
J17
.
The
fuel pump relay
J17
will only close if the engine is turning over. In other words, the relay is only earthed (via the engine control unit) when the engine control unit is receiving engine speed impulses.
Checking operation of fuel pump relay
Battery voltage at least 12.5 V
Remove driver's storage compartment
General body repairs, interior
Rep. Gr.
68
.
Connect
vehicle diagnostic, testing and information system
VAS 5051 A
Chapter
and select vehicle system
“01 - Engine electronics”
from list. When doing this the ignition must be switched on.
Initiate final control diagnosis
Chapter
and activate
activated charcoal filter solenoid valve 1
N80
.
The fuel pump relay (on the micro central electrics on the left of the driver's footwell, position
4
) should pick up and the fuel pump should run.
Press the
←
key to exit from function
“03 - Final control diagnosis”
.
Switch off ignition.
A - If the relay does not pick up:
Check voltage supply and activation of fuel pump relay as described in the following.
B - If relay picks up but fuel pump does not run:
Check voltage supply for fuel pump and components (by testing fuel pump relay)
Anchor
.
Checking voltage supply
Detach fuel pump relay
4
.
Connect multimeter (voltage measuring range) between contact
17
of relay socket and earth.
Specification: approx. battery voltage
If specification is not obtained:
Renew micro central electrics.
If reading matches specification:
Re-insert fuel pump relay.
Checking activation
Connect
adapter cable, 121-pin
V.A.G 1598/31
(test box) to wiring harness for engine control unit, but do not connect the engine control unit itself
Chapter
.
Use leads from
adapter set
V.A.G 1594 C
to bridge contacts
“1”
and
“65”
at test box.
Switch on ignition.
The fuel pump relay (on the micro central electrics on the left of the driver's footwell, position
4
) should pick up.
If the relay picks up now but not during the final control diagnosis:
Renew engine control unit
Chapter
“
Removing and installing engine control unit without protective housing
”
or
Chapter
“
Removing and installing engine control unit with protective housing
”
.
If the relay does not pick up:
Switch off ignition.
Detach jumper.
Detach fuel pump relay
4
.
Connect multimeter (voltage measuring range) between contact
19
of relay socket and earth.
Switch on ignition.
Specification: approx. battery voltage
If specification is not obtained:
Use current flow diagram to check wiring and repair if necessary.
If reading matches specification:
Check for open circuit and short to positive or earth in the following wiring:
Micro central electrics on left of driver's footwell, position 4
Contact
V.A.G 1598/31
Socket
16
65
Repair wiring connection if necessary.
If no fault is found:
Renew
fuel pump relay
J17
.
Reconnect the engine control unit.
Checking voltage supply to fuel pump and other components
Remove the following fuses:
On engine code
“AJK”
,
“ARE”
,
“AZA”
, remove
fuses in fuse holder
S228
,
S229
and
S234
(at positions
28
,
29
and
34
).
On engine code
“BES”
, remove
fuses in fuse holder
S228
,
S232
and
S234
(at positions
28
,
32
and
34
).
Initiate final control diagnosis
Chapter
and activate
activated charcoal filter solenoid valve 1
N80
.
For each of the following fuse positions in the fuse holder, connect the multimeter (voltage measurement range) between earth and one of the fuse contacts:
Fuse
Specification at one of the contacts
S228
approx. battery voltage
S229
approx. battery voltage
S232
approx. battery voltage
S234
approx. battery voltage
If the specifications are not obtained:
Repeat the test on the other fuse contact.
If the specifications are again not obtained:
Use current flow diagram to check wiring.
If no fault is found:
Renew
fuel pump relay
J17
.
Refit fuses.