wiring diagram AUDI A4 1999 B5 / 1.G AC System On Board Diagnostic Owner's Manual

01-38
Diagnostic Trouble Code (DTC) table, changes specific to vehicles 1997

Notes:
The following DTCs are no longer recognized beginning m.y. 1997:

00529 Speed info missing (sensor -G111- deleted).
00799 A/C engine coolant temperature (ECT) sensor -G110- (sensor deleted).
00801 A/C refrigerant high pressure switch -F118- (switch deleted).
01270 A/C clutch -N25- (Sensor -G111- deleted).
The following DTCs are new for 1997, or are current DTCs with additional references to 1997 changes. DTCs and component
references include various malfuction causes in the display below the DTC, etc.
VAG1551 scan tool display
Possible cause
Corrective action
00604
Back Pressure Flap Motor
Position Sensor -G113- in Air
Flow Flap Motor -V71-1)

Short circuit to ground /SP
Open circuit/short circuit to
positive /SP - Short circuit, open circuit in wiring or incorrect
terminal assignment (wires interchanged) of
connectors between -G113- and -E87-
- Air flow flap not operating freely
- -G113- in -V71- inoperative- Diagnose and repair short circuit,
open circuit in wiring or confirm
terminal assignment using wiring
diagram

- Check for free operation of air flow
flap3)
- Replace -V71-
Pa
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01-39

VAG1551 scan tool
display Possible cause
Corrective action
00792 3224
A/C Pressure Switch
-F129-

Short circuit to
ground /SP - Open circuit in wiring/connections between -F129-
and -E87-
- Malfunction in operation of coolant fan -V7- (stage 1)


- Condenser or radiator dirty.
- Malfunction in operation of coolant fan -V7- (stage 2)
by A/C pressure switch -F129-
- -F129- malfunction
- Excess or low refrigerant system pressure- Diagnose and repair short or open circuit
in wiring using wiring diagram.
- Test fan operation -V7- (stage 1) using
function 03 (Output DTM)
page 01
-42

- -V7- electrical test
page 01
-115
.
- Clean condenser and radiator.
- Test -V7- (stage 2) via A/C pressure
switch -F129- page 87
-67
).
- Test -F129- page 87
-67
.
- Check refrigerant system pressures
page 87
-192
.
Notes:

A/C pressure switch -F129- contains 2 switching elements. Via terminals 1 & 2, the compressor is shut off due to low or
excess refrigerant system pressure (switch open). Via terminals 3 & 4, the second speed coolant fan is switched on
(switch closed).
When -F129- terminals 1 & 2 open, excess refrigerant pressure is initially recognized by A/C control head -E87- and a
DTC is stored. If the measured outside temperature is between 0 C & 50 C (32 F & 122 F) and -F129- terminals 1 &
2 remain open for longer than 30 seconds, -E87- switches over from excess pressure to low pressure (Low pressure
switch function) page 01
-86
, Read measuring value block (Display group 01 compressor shut-off conditions).
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01-40

VAG1551 scan tool
display Possible cause
Corrective action
01206
Signal for time span
ignition off1)

implausible
signal /SP - Short or open circuit in wiring/connections
between instrument cluster and -E87-
- Instrument cluster malfunctioning.- Diagnose and repair short or open circuit in
wiring using wiring diagram.
- Check signal from instrument cluster using
function 08, Read measuring value block
page 01
-86
.
01274 4131
Air Flow Flap Motor -
V71- 2)

blocked or no
current /SP - Short or open circuit in wiring/connections
between -V71- and -E87-.
- Air flap or fresh/recirculated air flap
binding/sticking
- -V71- malfunctioning.- Diagnose and repair short or open circuit in
wiring using wiring diagram.
- Check air flap or fresh/recirculated air flap for
ease of movement.
- Check -V71- using function 03, Output
Diagnostic Test Mode (DTM) page 01
-42
.
1) 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, the 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.
2) -V71- operates the air flow flap as well as the fresh/recirculated air flap.
Pa
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01-41

VAG1551 scan tool
display Possible cause
Corrective action
01296
Sender for Outlet
Temperature, Center -
G191-

Short circuit to ground /SP

Open circuit/short circuit to
positive /SP - Short or open circuit in wiring/connections between -
G191- and -E87-
- Sensor -G191- malfunctioning- Diagnose and repair short or open
circuit in wiring using wiring
diagram
- -G191- electrical check page
01
-115

01297
Sender for Outlet
Temperature, Floor Outlet
-G192-

Short circuit to ground /SP

Open circuit/short circuit to
positive /SP - Short or open circuit in wiring/connections between -
G192- and
-E87-.
- -G192- malfunctioning- Diagnose and repair short or open
circuit in wiring using wiring
diagram.
- -G192- electrical check page
01
-115

65535
A/C control head -E87-

Malfunction
- Short or open circuit in wiring/connections between
terminal -15- or -31- to -E87-, contact resistance or
loose connection
- -E87- malfunctioning- Diagnose and repair short or open
circuit in wiring to -E87- using wiring
diagram

- Replace A/C control head -E87-
Pa
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01-46
Output Diagnostic Test Mode (DTM) table

VAG1551 scan tool display
Specified function
Corrective action
A/C Clutch N25








Notes: - N25 clicks every 2-seconds
- Output of A/C control head -E87- is switched from 0 V to
12 V every 2-seconds2) - Test voltage supply for -
N25- (via A/C Clutch
Relay J44) using wiring
diagram
- Repair or replace -N25-
page 87
-90

- Test circuit and
connectors between A/C
control head -E87-, J44
and -N25- using wiring
diagram
- Replace -E87-

"A/C compressor on" output to
Engine Control Module (ECM)
and -E87- terminal -C12- is
also actuated at the same
time1)
Output of -E87- switched from 0 V to 12 V every 2
seconds can be confirmed by switching compressor on
and off using the "ECON" button while reading the
measured value block of engine control module
Repair Manual, Fuel Injection and Ignition System,
Repair Group 01)

1)Test this "A/C compressor on" signal only if complaints exist. ECM uses signal to compensate for engine load when
compressor engages Repair Manual, "Fuel Injection & Ignition," Repair Group 24 . ECM is capable of switching off the A/C compressor from this signal. Confirm via function 08, Read measuring value block,
page Page 01
-63
, display group 01 and Fuel Injection and Ignition System Repair Manual, Repair group 01: Read
measured value block of ECM with engine running and at same time switch compressor on and off.
Pa
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01-47

VAG1551 scan tool
display Specified function
Corrective action
Fresh Air Blower V2





Caution:
Coolant Fan coming on !
Warning:
The next forwarding of program with the
button will cause Coolant Fan V7 to come
on. Keep clear of Coolant Fan! - V2 runs for 2 seconds with 0V, 3V, 6V, 9V,
12V, 15V, 0V applied.
- Check that fresh air blower operates freely
- Test ground connection to Control Module
for Fresh Air Blower J126 using wiring
diagram
- J126 electrical test page 01
-115
- Replace -E87-
Coolant Fan V7
- V7 (1st stage) switched on and off every 5
seconds - Test wiring/connections between -E87- and
J26 for open circuit or short circuit to positive
using wiring diagram
- Coolant Fan Control (FC) Relay J261)
electrical test page 01
-115

- Replace -E87-
Fresh Air/Recirculating
Flap Two-Way Valve N63
2) - N63 switches from fresh air to recirculating
air every 5 seconds - Check vacuum supply to -N63-
page 87
-187

- Test voltage supply to N63 and circuit to -
E87- for open circuit or short circuit to ground
using wiring diagram
Pa
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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
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01-49

VAG1551 scan tool display
Specified function
Corrective action
Footwell/Defroster Flap Motor V85




Note:

Wait until footwell/defroster flap is
at "defrost" stop before pressing
button.
- V85 moves from stop to stop
(fresh air blower running, air flow
switches from footwell to defrost) - Test wiring/connections between V85 and -
E87- for open circuit or wrong connection
using wiring diagram
- Check for free operation of
footwell/defroster flap
- V85 electrical test page 01
-115
- Replace -E87-
Air Flow Flap Motor V71 1)
- V71 moves from stop to stop
(fresh air blower running, air flow
changes) - Test wiring/connections between V71 and -
E87- for open circuit or wrong connection
using wiring diagram
- Check for free operation of air flow flap
- V71 electrical test page 01
-115
- Replace -E87-
1) For m.y. 1997, -V71- operates the air flow flap as well as the fresh/recirculated air flap.
Pa
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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
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01-51

VAG1551 scan tool display
Specified function
Corrective action
Segment test
- All segments of A/C control head -
E87- are switched on and off every 3
seconds - Replace bulbs page 87
-126
- Replace -E87-
Outside Air Temperature
Display G106 in Auto Check
System1) - Temperature display in Auto Check
System1) begins counting up at 3
second intervals - Test wiring/connections between -E87- and
G106 for open circuit or short circuit using wiring
diagram
- Test positive and ground connections to G106
for open circuit using wiring diagram
- Test Auto Check System1)
- Replace -E87-
1) If equipped.
Pa
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