1999 AUDI A6 relay

24-55


A - If relay does not trigger:
B - If relay triggers, but Fuel Pump (FP) does not run:
Check voltage supply of Fuel Pump (FP) relay
Fuel Pump (FP) relay (at position 4 of central electrics in driver's
footwell, left) must trigger and Fuel Pump (FP) must run.
- Check voltage supply of Fuel Pump (FP) relay Page 24
-55
.
- Checking activation of Fuel Pump (FP) relay Page 24
-56
.
- Check voltage supply for Fuel Pump (FP) and components (via Fuel
Pump -FP- relay) Page 24
-58
.
- Remove Fuel Pump (FP) relay.

- Connect multimeter to terminal 17 of relay socket and Ground (GND)
for voltage measurement.

Specification: approx. battery voltage
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24-56
If specified value is not obtained:

- Replace central electrics.

Checking activation of Fuel Pump (FP) relay

- Switch ignition off.

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

- Switch ignition on.

- Bridge terminals 1 and 65 at test box using wires
from VAG1594A adapter test kit.

If relay triggers now, but didn't during output DTM:
If relay does not trigger:
Fuel Pump (FP) relay (at position 4 of central electrics in driver's
footwell, left) must trigger.
- Replace Engine Control Module (ECM) Page 24
-23
- Switch ignition off.
- Remove cable bridge.
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p://127.0.0.1:8080/audi/servlet/Dis
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pair&id=AUDI.B5.FU06.24.1

- Remove Fuel Pump (FP) relay.
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24-58

- Repair open circuit or short circuit if
necessary.
If no malfunctions are detected:

- Replace Fuel Pump (FP) relay -J17-.

- Re-connect Engine Control Module (ECM).

Check voltage supply for Fuel Pump (FP) and
components

- Remove fuses S228, S232, and S234 (positions 28, 32, and 34) from
fuse holder.
- Initiate output Diagnostic Test Mode (DTM) Page 01
-49
and activate
Evaporative Emission (EVAP) canister purge regulator valve -N80-.
- Connect multimeter for voltage measurement to Ground (GND) and to
one terminal of following fuses in fuse holder. Circlip
Specified value at one of the terminals
S228 approx. battery voltage
S232 approx. battery voltage
S234 approx. battery voltage
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.24.1

24-59
If specified values are not obtained:

- Repeat test at another terminal of fuse socket.
If specified values are not obtained again:

- Check wire connections.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations If no malfunctions are detected:

- Replace Fuel Pump (FP) relay -J17-.

- Re-insert fuses.
Pa
ge 68 of 81 Motronic fuel in
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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pair&id=AUDI.B5.FU06.24.1

24-64

Voltage supply for Mass Air Flow (MAF)
sensor, checking

Test requirements:

Fuse for Mass Air Flow (MAF) sensor OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations

Fuel Pump (FP) relay OK; checking Page 24
-53
.

Note:
Voltage is supplied to Mass Air Flow (MAF)
sensor from Fuel Pump (FP) relay.

- Disconnect connector from Mass Air Flow (MAF)
sensor.

- Connect multimeter for voltage measurement as follows.Harness connector
Terminal
Measure to
2 Engine Ground (GND)
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pair&id=AUDI.B5.FU06.24.1

24-65
If specified value is not obtained:

- Check wire connection from terminal 2 of
connector to Fuel Pump (FP) relay via fuse for
open circuit and short circuit to Ground (GND):

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
- Repair open circuit or short circuit if
necessary.

Note:
Ground (GND) from the ECM is present at terminal 3 of connector.
If specified value is not obtained: - Connect multimeter to terminal 2 and terminal 3 of connector for
voltage measurement.
- Operate starter briefly (engine can also start).

Specification: approx. battery voltage
- Check wire connections Page 24
-67
.
Pa
ge 76 of 81 Motronic fuel in
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11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.24.1