display AUDI A4 1999 B5 / 1.G AC System On Board Diagnostic User Guide

out in sequence. If the printer is switched off, the button must be pressed in order to
display the next DTC.
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01-19

If DTC are displayed:

- Refer to DTC table and check and repair as
instructed page 01
-22
.

- Operate A/C system and check DTC memory
(function 02) to confirm repair.

- Erase DTC memory (function 05).

- Confirm A/C control head -E87- coding (function
01), and if necessary code -E87- (function 07).

- Perform basic setting (function 04).

- Check DTC memory (function 02), if
malfunctions are stored, erase DTC memory
(function 05).

- VAG1551 Scan Tool (ST) can be returned to the
function mode by pressing the button. Rapid data transfer
HELP
Select function XX

Indicated on display (function selection)
- End output (function 06) page 01
-56
.
- Switch ignition off and disconnect VAG1551 Scan Tool (ST) from Data
Link Connector (DLC).
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01-20

If no DTC are displayed and A/C system
complaints exist (e.g. compressor does not
run or only occasionally, system control
unsatisfactory, speed of fresh air blower
cannot be regulated etc.):

- Read measuring value block (function 08).

- Perform Output Diagnostic Test Mode (DTM)
(function 03).

- Check A/C system cooling performance page
87
-213
.

- VAG1551 Scan Tool (ST) can be returned to the
function mode by pressing the button. Rapid data transfer
HELP
Select function XX

Indicated on display (function selection)
- End output (function 06) page 01
-56
.
- Switch ignition off and disconnect VAG1551 Scan Tool (ST) from Data
Link Connector (DLC).
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01-21

Notes:

1997 If A/C control head -E87- is unable to
determine the duration of time when ignition is
off ("standing time"), DTC 01206 "signal for time
span ignition off" is loaded into memory. The
A/C control head will then default to a standing
time greater than 4 hours. The actual measured
values of the outside temperature sensor are
then used as instantaneous outside and engine
temperature inputs for A/C system control.
When the "heating" mode is selected under
these conditions, fresh air blower -V2- has a
delayed start (even when the actual standing
time is less than 4 hours and the engine is
warm) page 01
-86
, Read Measuring Value
Block. The outside air temperature display -
G106- may also indicate incorrect outside
temperature values.

If both display fields of the A/C control head do
not light with ignition switched on check control
head coding Page 01
-57
.
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01-22
Diagnostic Trouble Code (DTC) table

Notes:

DTC changes affecting m.y. 1997 vehicles page 01
-38
.
Diagnostic Trouble Codes (DTC) recognized by A/C control head -E87- and displayed on VAG1551 Scan Tool (ST)
starting on page 01
-24
.
If malfunctions occur only occasionally or if the DTC memory was not erased after repairs, such DTC are displayed as
"sporadic faults." (The contents of DTC memory is retained until erased, "permanent memory").
DTCs and flash codes (only for specific components) appear only in the printout in operating mode -1-, (Rapid data
transfer).
In addition to displayed DTC and affected component descriptions, malfunction cause information is listed in the table
below the DTC code.
After performing repairs and operating the A/C system, DTC memory must always be checked again to confirm the repair.
Before replacing a suspected malfunctioning component, check all appropriate wiring, connections, harness connectors
and Ground (GND) connections.
When checking for the cause of sporadic faults, check all plug connections and wiring between A/C control head -E87-
and any component recognized as being inoperative using wiring diagram.
After replacing AC/heating system components, always perform basic setting (function 04), check DTC memory (function
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01-23
Notes

If 22 C (72 F) is always displayed after switching ignition off and on, regardless of last setting, check power supply
(terminal 30) to A/C control head -E87- using wiring diagram. If a malfunction is recognized at an air/temperature distribution flap motor potentiometer, air distribution can be altered by
pressing buttons on A/C control head -E87-.
To switch display from C (Celsius) to F (Fahrenheit)(and vice versa), press "Temperature +" button while holding
"recirculating air" button. If no DTC are displayed and air conditioning system complaints exist (e.g. compressor does not run or only occasionally,
system control unsatisfactory, speed of fresh air blower cannot be regulated etc.), perform function 03 "Output Diagnostic
Test Mode (DTM)" and 08 "Read Measuring Value block."
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01-24

VAG1551 scan tool
display Possible cause
Corrective action
00000
No DTC recognized If "no DTC recognized appears after performing repairs, OBD is ended.
00529 2122
Speed information
missing /SP1) - Open circuit in wiring between Engine Control Module
(ECM), instrument cluster and A/C control head -E87-
- ECM and instrument cluster supply an unusable engine
speed signal - Diagnose and repair open circuit in
wiring using wiring diagram
- Read measuring value block
page 01
-63

- Test engine speed signal
Repair Manual, Fuel Injection &
Ignition, Repair Group 24
00532 2234
Supply voltage

Signal too low /SP - Voltage drops in electrical system to levels of less than
9.5 V2)
- Contact resistance in cable connection to A/C
Refrigerant Low Pressure Switch -F73- - Test Generator (GEN) and Voltage
Regulator (VR)
Repair Manual, Engine
Mechanical, Repair Group 27
- Diagnose and repair contact
resistance using wiring diagram
1)This fault may be generated during Output Diagnostic Test Mode (DTM) (no engine speed signal recognized although A/C
compressor speed detected).
2) If voltage at -E87-connector -C3- drops below 9.5 V, compressor switches off for a minimum of 25 seconds. Compressor
switches on again when voltage exceeds 10.8 V.
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01-25

VAG1551 scan tool display
Possible cause
Corrective action
00600
Temperature Regulator Flap Motor
Position Sensor -G92- for
Temperature Regulator Flap Motor
V681)
Short circuit to ground /SP

Open circuit/short circuit to
positive /SP
Adaptation limit exceeded
Mechanical malfunction. - Short circuit, open circuit in wiring or
incorrect terminal assignment (wires
interchanged) of connectors between -G92-
and -E87-
- Temperature flap not operating freely
- -G92- in -V68- inoperative- Diagnose and repair short circuit,
open circuit in wiring or confirm
terminal assignment using wiring
diagram

- Check for free operation of
temperature flap
- Replace -V68-
00601
Central Flap Motor Position Sensor
G112 in Central Air Flap Motor V70
Short circuit to ground /SP

Open circuit/short circuit to
positive /SP
Adaptation limit exceeded2)
Mechanical malfunction - Short circuit, open circuit in wiring or
incorrect terminal assignment (wires
interchanged) of connectors between -
G112- and -E87-
- Central flap not operating freely
- -G112- in V70 inoperative- Diagnose and repair short circuit,
open circuit in wiring or confirm
terminal assignment using wiring
diagram

- Check for free operation of central
flap3)
- Replace -V70-
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1)If a fault exists at potentiometer -G92-, flap motor V68 can be set manually by operating "+" or "-" button for temperature
selection (display range between 0 C and 50 C). 2)This fault only recognized during the basic setting.
3)Both end stops must be reached.
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01-26

VAG1551 scan tool display
Possible cause
Corrective action
00602
Footwell/Defrost Flap Motor
Position Sensor G114 in
Footwell/Defroster Flap Motor V85
Short circuit to ground /SP

Open circuit/short circuit to
positive /SP

Adaptation limit exceeded1)

Inoperative - Short circuit, open circuit in wiring or
incorrect terminal assignment (wires
interchanged) of connectors between -G114-
and -E87-
- Footwell/defroster flap not operating freely
- -G114- in -V85- inoperative- Diagnose and repair short circuit,
open circuit in wiring or confirm
terminal assignment using wiring
diagram

- Check for free operation of
footwell/defroster flap2)
- Replace -V85-
00603
Footwell/Defroster Flap Motor V85

Blocks or de-energized /SP - Short circuit, open circuit in wiring or
incorrect terminal assignment (wires
interchanged) of connectors between V85
and -E87-
- Footwell/defroster flap flap not operating
freely
- -V85- inoperative- Diagnose and repair short circuit,
open circuit in wiring or confirm
terminal assignment using wiring
diagram

- Check for free operation of
footwell/defroster flap
- Check -V85- using function 03
(Output DTM) page 01
-42

1)This fault only recognized during basic setting.
2) Both end stops must be reached.
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