Checking radiator fan V7 and radiator fan 2 V177: Audi 4.2 (BAS)

Checking
radiator fan
V7
and
radiator fan 2
V177
Special tools and workshop equipment required
Hand-held multimeter
V.A.G 1526 C
Voltage tester
V.A.G 1527 B
Auxiliary measuring set
V.A.G 1594 C
Test box
V.A.G 1598/31
Vehicle diagnostic, testing and information system
VAS 5051B
Test sequence
Connect up the
vehicle diagnostic, testing and information system
VAS 5051B
.
Switch on ignition.
Press
Vehicle self-diagnosis
key, select vehicle system
“01 - Engine electronics”
system and press
→
key to activate function.
Display on
VAS 5051B
:
From menu
1
, select function
“005 - Final control diagnosis”
and press
→
key to activate function.
Press the
→
button until the radiator fan control 2 is activated.
The
radiator fan control unit 2
J671
activates the
radiator fan 2
V177
(right-side) once, slowly increasing to full speed.
Press the
→
button until the radiator fan control 1 is activated.
The
radiator fan control unit
J293
activates the
radiator fan
V7
(left-side) once, slowly increasing to full speed.
Press
←
key to exit from function
“005 - Final control diagnosis”
.
If fan activation does not react as described:
Establish the preconditions for the radiator fans to activate based on the criteria mentioned above (e.g. switch on air conditioner, increase engine temperature as appropriate).
Display on
VAS 5051B
:
From menu
1
, select function
“011 - Measured values”
and press
→
key to activate function.
Display on
VAS 5051B
:
1
Enter display group
Press keys
1
3
5
on keypad
1
to select
“Display group 135”
and confirm entry by pressing
Q
key.
Display on
VAS 5051B
:
Check display in display zones
2
and
3
.
Duty cycle, fan 1 (left-side): at least 10%
Duty cycle, fan 2 (right-side): at least 10%
Note
In the event of a fan request from the air conditioner and/or if the coolant temperature is greater than 98 °C, the duty cycle must rise above 10 % and the fans must start up.
If the duty cycle does not rise above 10 %:
Read out fault memory of engine control unit.
Rectify the faults indicated as necessary.
If the fan concerned does not start up, even though the duty cycle is above 10 %:
Check the
radiator fan
V7
Anchor
and
radiator fan 2
V177
Anchor
.
Checking
radiator fan
V7
(left-side)
Radiator fan single fuse
S42
OK (in 8-position relay carrier, position 19).
Radiator fan fuse for 1st and 2nd speed
S146
OK (in 8-position relay carrier, position 21).
Unplug electrical connector
arrow
.
Connect
multimeter
V.A.G 1526 C
as follows to measure voltage:
Connector
Contact
Measure against
1
Battery positive
2
Engine earth
Specification: approx. battery voltage
If the specifications are not obtained:
Repair wiring connection if necessary.
If the specifications are obtained:
Connect
multimeter
V.A.G 1526 C
as follows to measure voltage:
Connector
Contact
Measure against
3
Engine earth
Specification: approx. battery voltage
If specification is not obtained:
Repair wiring connection if necessary.
If specification is obtained:
Connect
multimeter
V.A.G 1526 C
between contacts
3
and
4
to measure voltage.
Vehicle diagnostic, testing and information system
VAS 5051B
connected, ignition switched on
Vehicle self-diagnosis
selected, vehicle system
“01 - Engine electronics”
activated.
Display on
VAS 5051B
:
From menu
1
, select function
“005 - Final control diagnosis”
and press
→
key to activate function.
Press the
→
button until the radiator fan control 1 is activated.
The voltage value must slowly fall from approximately battery voltage to approximately 8 V (and then rise again).
Press
←
key to exit from function
“005 - Final control diagnosis”
.
Switch off ignition.
If specification is not obtained:
Connect
test box
V.A.G 1598/31
to connectors of wiring harness; do not connect engine control unit. Connect earth clip of test box to earth (not shown in illustration)
Rep. Gr.
24
.
WARNING
To prevent damage to the electronic components, select appropriate measuring range before connecting the measuring cables and observe the test requirements.
Check for open circuit and short to positive or earth in the following wiring:
Connector
Contact
Test box
V.A.G 1598/31
Socket
4
66
Repair wiring connection if necessary.
If no fault is found:
Renew
radiator fan
V7
with
radiator fan control unit
J293
Chapter
.
Checking
radiator fan 2
V177
(right-side)
Radiator fan fuse for 2nd speed
S104
OK (in 8-position relay carrier, position 22).
Radiator fan fuse for 1st and 2nd speed
S146
OK (in 8-position relay carrier, position 21).
Detach electrical connector
2
from bracket and unplug.
Connect
multimeter
V.A.G 1526 C
as follows to measure voltage:
Connector
Contact
Measure against
1
Engine earth
4
Battery positive
Specification: approx. battery voltage
If the specifications are not obtained:
Repair wiring connection if necessary.
If the specifications are obtained:
Connect
multimeter
V.A.G 1526 C
as follows to measure voltage:
Connector
Contact
Measure against
2
Engine earth
Specification: approx. battery voltage
If specification is not obtained:
Repair wiring connection if necessary.
If specification is obtained:
Connect
multimeter
V.A.G 1526 C
between contacts
2
and
3
of connector to measure voltage.
Vehicle diagnostic, testing and information system
VAS 5051B
connected, ignition switched on
Vehicle self-diagnosis
selected, vehicle system
“01 - Engine electronics”
activated.
Display on
VAS 5051B
:
From menu
1
, select function
“005 - Final control diagnosis”
and press
→
key to activate function.
Press the
→
button until the radiator fan control 2 is activated.
The voltage value must slowly fall from approximately battery voltage to approximately 8 V (and then rise again).
Press
←
key to exit from function
“005 - Final control diagnosis”
.
Switch off ignition.
If specification is not obtained:
Connect
test box
V.A.G 1598/31
to connectors of wiring harness; do not connect engine control unit. Connect earth clip of test box to earth (not shown in illustration)
Rep. Gr.
24
.
WARNING
To prevent damage to the electronic components, select appropriate measuring range before connecting the measuring cables and observe the test requirements.
Check for open circuit and short to positive or earth in the following wiring:
Connector
Contact
Test box
V.A.G 1598/31
Socket
3
104
Repair wiring connection if necessary.
If no fault is found:
Renew
radiator fan 2
V177
with
radiator fan control unit 2
J671
Chapter
.