AUDI A4 1998 B5 / 1.G AC System Electrical Testing User Guide

01-123
Temperature sensor resistances (based on ambient temperature, resistance in k ohm) Temperature measured at mounting
location of sensor Instrument Panel
Interior
Temperature
Sensor
-G56- Outside Air Temperature Sensor -G17- and Fresh Air
Intake Duct Temperature Sensor -G89-
-40 C (-40 F)
(100) (34.7)
-30 C (-22 F) (52.7) 18.1
-20 C (1 F) (28.6) 9.95
-10 C (14 F) 16.2 5.59
0 C (32 F) 9.40 3.28
5 C (41 F) 7.27 2.54
10 C (50 F) 5.66 1.99
15 C (59 F) 4.45 1.57
20 C (68 F) 3.50 1.25
25 C (77 F) 2.79 1.00
30 C (86 F) 2.23 0.80
35 C (95 F) 1.80 0.65
40 C (104 F) 1.45 0.53
50 C (122 F) 0.79 0.36
60 C (140 F) 0.67 0.25
Pa
ge 11 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

70 C (158 F)
0.47 -
80 C (176 F) 0.33 -
Pa
ge 12 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-124
Test No. 3 (Fresh Air Blower V2 and Control module for fresh air blower J126) VAG1598/11 adapter cable Measuring range: Voltage measurement (20 V)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
3.1 16 and
ground Control module
for fresh air
blower J126
Ignition
on - Voltage less
than 5 V
- Blower does
not run. - Determine and rectify short circuit to positive in
wiring/connections between J126 and -E87-
using wiring diagram.
- Replace J126
3.2 14 and
ground Voltage supply for
Fresh Air Blower
V2 Ignition
on - approx.
battery
voltage - Repair voltage supply using wiring diagram.
3.3 11 and
ground Voltage supply for
J126 (via V2) Ignition
on - approx.
battery
voltage
Pa
ge 13 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-125

VAG1598/11 adapter cable
LED voltage tester US 1115
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified values
Corrective action
3.4 13 + 16 Control module for
fresh air blower -
J126-
Ignition
on - LED in voltage
tester comes on
- Fresh air blower
runs - Determine and rectify open circuit in
wiring/connections between -J126- and -
E87-.
- Check Fresh Air Blower V2
operates freely.
- Replace -J126-.
Pa
ge 14 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-126
Test No. 4 (air/temperature distribution flap motors and related potentiometers) VAG1598/11 adapter cable Measuring range: Resistance measurement (20 kilo ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified values
Corrective action
4.1 52 +

28
29
37
30 Potentiometer
(in flap motor)
-G92- (-V68-)
-G112- (-V70-
)
-G113- (-V71-
)
-G114- (-V85-
)
- greater than 0.1kW and less
than 5.7kW (depends on
position of flap motor) - Determine and rectify open circuit
in wiring, contact resistance or short
circuit using wiring diagram.
- Replace applicable flap motor
page 87
-106
.
4.2 8 +

28
29
37
30 Potentiometer
(in flap motor)
-G92- (-V68-)
-G112- (-V70-
)
-G113- (-V71-
)
-G114- (-V85-
)
- greater than 0.1kW and less
than 5.7kW (depends on
position of flap motor)
Notes:

Potentiometer resistance (Specified values: 3.6 k to 5.7 k between flap motor terminal 3 and 4) can only be measured
Pa
ge 15 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

directly at the flap motor (parallel circuit).
Potentiometers resistance (between flap motor terminal 3 and 5, plus 4 and 5) depends on the position of the flap motor.
Measure only with installed flap motor. The upper specified value is not achieved in test steps 4.1 and 4.2 (to achieve this
value, all connectors of the other flap motors would have to be unplugged during the measurement, parallel circuit).
If -E87- recognizes DTC" potentiometer short circuit to ground or open circuit/short circuit to positive", test all
potentiometers.
Pa
ge 16 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-127

VAG1598/12 adapter cable Measuring range: Resistance measurement (200 ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
4.3 2 + 10 Temperature Regulator
Flap Motor -V68- 20 W to 100
W - Determine and rectify open circuit in
wiring, contact resistance or short circuit
using wiring diagram.
- Replace applicable flap motor page
87
-106
.
4.4 4 + 12 Central Flap Motor -V70- 20 W to 100
W
4.5 5 + 13 Air Flow Flap Motor -V71- 20 W to 100
W
4.6 3 + 11 Footwell/Defroster Flap
Motor -V85- 20 W to 100
W
Pa
ge 17 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-128
Test No. 5 (A/C Compressor Speed Sensor -G111-, refrigerant pressure switches -F118-, -F73- and Interior
Temperature Sensor Fan -V42-)
Note:
Electrical test steps 5.1 to 5.4 do not apply to vehicles equipped with Nippondenso compressors (A/C compressor speed
sensor G111 is not installed on Nippondenso compressors). VAG1598/11 adapter cable Measuring range: Resistance measurement (20 kilo ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
5.1 5 + 49 A/C Compressor
Speed Sender -G111-
- 0.8 kW to
1.5 kW - Determine and rectify open circuit in
wiring, contact resistance or short circuit
using wiring diagram.
- Replace -G111- page 87
-63
.
5.2 5 and
ground A/C Compressor
Speed Sender -G111-
- greater
than
2 kW - Determine and rectify short circuit using
wiring diagram.
- Replace -G111- page 87
-63
.
Pa
ge 18 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-129

VAG1598/11 adapter cable Measuring range: Voltage measurement (20 V)
Test
step VAG1598
socket Test of
Test conditions
- additional steps Specified
values Corrective action
5.3 5 and
ground A/C Compressor Speed
Sender -G111-
Engine running Compressor not
running - less than 1
V - Determine and rectify short
circuit using wiring diagram.
VAG1598/11 adapter cable Measuring range: Voltage measurement (2 V)
Note: additional test steps before proceeding with this test. Test
step VAG1598
socket Test of
Test conditions
- additional steps Specified values
Corrective
action
5.4 5 and
ground A/C Compressor
Speed Sender -
G111-
Engine running Compressor running
- Relay for A/C Clutch removed
- Bridge terminals 30 + 87 at relay
connector base (A/C Clutch
switched on) - greater than 0.05 V
(depends on engine
speed) - Replace -G111-
page 87
-63
.
Pa
ge 19 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-130

VAG1598/11 adapter cable Measuring range: Resistance measurement (200 ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
5.5 2 + 49 A/C Refrigerant High
Pressure Switch -F118-
- less than
20 W - Determine and rectify open circuit in
wiring or contact resistance using wiring
diagram.1)
- Replace -F118- page 87
-25
.
1)If code 1 "high-pressure switch -F118 open" is displayed in measuring value block 1 as a compressor cut-off condition: -Test
connections to -F118- for loose terminal using wiring diagram. -Test actuation of Coolant Fan V7 stage 1 Output Diagnostic Test Mode, page 01
-42
. Test actuation of Coolant Fan V7 stage 2 page 01
-42
. If no fault can be determined, check for
refrigerant system malfunction, refrigerant system pressure test page 87
-190
.
Pa
ge 20 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2