wiring diagram AUDI A4 1995 B5 / 1.G ATQ Engine Motronic Injection System Servicing Workshop Manual

24-38

Checking voltage supply

Test requirements:

Fuel Pump (FP) OK, checking Page 24
-
49
.

Fuse for fuel injectors OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

- Disconnect harness connector at the fuel
injector to be tested.

If LED does not light up: - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Engine Ground (GND)
- Switch ignition on.

LED must light up.
Pa
ge 45 of 78 Motronic in
jection s
ystem, servicin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.1

Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Check wire connection between terminal 1 and fuse for injector valves
for open circuit:
Pa
ge 46 of 78 Motronic in
jection s
ystem, servicin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.1

24-53


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
-21
.
- Remove cable bridge.
- Remove Fuel Pump (FP) relay.

If specified value is not obtained:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect multimeter to terminal 19 of relay socket and Ground (GND)
for voltage measurement.

Specification: approx. battery voltage
- Check wire connections.
Pa
ge 63 of 78 Motronic in
jection s
ystem, servicin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.1

24-55

- Connect multimeter for voltage measurement to
Ground (GND) and to one terminal of the
following fuses in the fuse holder.

Fuse
Specified value at one of the
terminals
S228 approx. battery voltage
S229 approx. battery voltage
S234 approx. battery voltage
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 binder If no malfunctions are detected:

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

- Re-insert the fuses.
Pa
ge 65 of 78 Motronic in
jection s
ystem, servicin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.1

24-57

Test requirements:

Coolant Temperature at least 80 C.

Electrical consumers switched off (radiator
fan must NOT run during test).
A/C switched off.
Fuse for Mass Air Flow (MAF) sensor OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

Checking function

- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .

Engine must run at idle for this.Rapid data transfer
HELP
Select function XX

When indicated on display:
-
Press buttons -0- and -4- to select "Initiate basic setting" and press -Q-
Pa
ge 67 of 78 Motronic in
jection s
ystem, servicin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.1

24-61

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

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

Note:
Voltage is supplied to Mass Air Flow (MAF) sensor from Fuel Pump (FP)
relay.
If specified value is not obtained:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect multimeter for voltage measurement as follows.Harness connector
Terminal
Measure to
3 Engine Ground (GND)
- Operate starter briefly.

Specification: approx. battery voltage
- Check wire connection from terminal 3 of connector to Fuel Pump (FP)
relay via fuse for open circuit and short circuit to Ground (GND):
Pa
ge 73 of 78 Motronic in
jection s
ystem, servicin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.1