instrument panel AUDI A4 1998 B5 / 1.G AC System On Board Diagnostic Workshop Manual

01-28

VAG1551 scan tool display
Possible cause
Corrective action
00779 3133
Outside Air Temperature Sensor G17

Short circuit to ground /SP

Open circuit/short circuit
to positive /SP - Short circuit or open
circuit
between -G17- and -
E87-
- -G17- malfunction- Diagnose and repair short circuit or open circuit in
wiring using wiring diagram
- -G17- electrical test page 01
-115
00785 3211
Instrument Panel Interior Temperature
Sensor G56

Short circuit to ground /SP

Open circuit/short circuit to
positive /SP - Short circuit or open
circuit
between -G56- and -
E87-
- -G56- malfunction- Diagnose and repair short circuit or open circuit using
wiring diagram
- -G56- electrical test page 01
-115
00787 3213
Fresh Air Intake Duct Temperature
Sensor G89

Short circuit to ground /SP
- Short circuit or open
circuit
between -G89- and -
E87-
- -G89- malfunction- Diagnose and repair short circuit or open circuit in
wiring using wiring diagram
- -G89- electrical test page 01
-115
Pa
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ystem, On Board Dia
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01-30

VAG1551 Scan Tool display
Possible cause
Corrective action
00785 3211
Instrument panel
interior temperature
sensor
-G56
Short circuit or open circuit between
instrument panel interior temperature
sensor -G56- and A/C control head -E87- - Locate short circuit or open
circuit using wiring diagram and
repair
Short circuit to
Ground /SP
Open/Short
circuit to B+ /SP Instrument panel interior temperature
sensor -G56- malfunctioning - Check instrument panel interior
temperature sensor -G56-
electrical testing, page 01
-115

Note for DTC 00785:
For the A/C control head -E87-, the instrument panel interior temperature sensor -G56- is installed with only one display in the
A/C control head -E87-. instrument panel interior temperature sensor-G56- cannot be checked or replaced individually, if
malfunctioning replace A/C control head -E87- completely. VAG1551 Scan Tool display
Possible cause
Corrective action
00796 6) 3234
Interior temperature
sensor fan-V42
Open circuit in power supply to -V42- or in
wiring connection between -V42- and -E87- - Locate and repair open
circuit using wiring diagram
Blocked or no
voltage /SP Interior temperature sensor fan -V42-
malfunctioning - Replace A/C control head -
E87-
6) For an A/C control head -E87- with only one display, the interior temperature sensor fan -V42- is installed in the A/C control
head -E87-; if malfunctioning replace complete unit.
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For the A/C control head -E87-, the instrument panel interior temperature sensor -G56- is installed with only one display in
the -E87-. -V42- and -G56- are not individually replaceable. If -E87- is malfunctioning, they must be replaced together.
A/C control heads with one display indicate that output diagnostic test mode is completed after activation of the last
component ("END" is indicated on the Scan Tool display).
Pa
ge 60 of 91 A/C s
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01-44

Starting output Diagnostic Test Mode (DTM)

- Start engine, switch on compressor (press
"Auto" button), adjust air flow to center
instrument panel outlets only.

- Connect Scan Tool VAG1551 or 1552 in
operating mode -1-, enter address word 08 "A/C
Heating Electronics" and move forward in
program until "select function XX" appears in the
display.

- Switch on printer by pressing the PRINT button
(indicator lamp in button comes on).

- Check DTC memory page 01
-18
.

- Note any stored DTCs for reference and move
forward in program until "select function XX"
appears in the display. Rapid data transfer
HELP
Select function XX

Indicated on display (function selection)
- Press buttons -0- and -3-.
Rapid data transfer
Q
03 - Output Dia
gnostic Test Mode

Indicated on display
- Press -Q- button to confirm input.
Pa
ge 61 of 91 A/C s
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01-48

VAG1551 scan tool display
Specified function
Corrective action
Temperature Regulator Flap
Motor V68




Note:

Wait until temperature flap
is in "heat" position before
pressing button
- V68 moves from stop to stop (fresh air
blower running, temperature of air at outlets
changes) - Test wiring/connections between V68
and -E87- for open circuit or wrong
connection using wiring diagram
- Check for free operation of temperature
flap
- V68 electrical test page 01
-115
- Replace -E87-
Central Air Flap Motor V70


Notes:

Wait until central flap is at
"air distribution to footwell/
defroster flap" position
before pressing button Close all instrument panel
air outlets. - -V70- moves from stop to stop (fresh air
blower running, air flow switches from
footwell/defrost to instrument panel air
outlets) - Test wiring/connections between -V70-
and -E87- for open circuit or wrong
connection using wiring diagram
- Check for free operation of central flap
- -V70- electrical test page 01
-115
- Replace -E87-
Pa
ge 69 of 91 A/C s
ystem, On Board Dia
gnostic
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01-50

VAG1551 scan tool
display Specified function
Corrective action
Interior Temperature
Sensor Fan V42 - V42 (for temperature sensor in
instrument panel) is switched on and off
every 5 seconds1) - Test wiring/connections between V42 and -E87- for
open circuit or short circuit to ground using wiring
diagram
- Test voltage supply for V42 using wiring diagram
- Check intake slot and intake hose for
restriction page 87
-145

- Replace -E87-
1)Confirm operation by blowing smoke over intake slot on center of instrument panel.
Pa
ge 71 of 91 A/C s
ystem, On Board Dia
gnostic
(OBD
)
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yp
e=re
pair&id=AUDI.B5.HA01.01.1