AUDI A4 1997 B5 / 1.G AC System On Board Diagnostic Repair 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-
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Adaptation limit exceeded2)
Inoperative 1) For m.y. 1997, -V71- operates the air flow flap as well as the fresh/recirculated air flap. 2) This DTC only recognized during basic setting. 3) Both end stops must be reached.
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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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When -F129- is recognized to open 30 times during a driving period (Eg.: intermittent contact), the compressor is switched
off. The compressor can be switched on again by pressing the "compressor on" button or by switching ignition off (and
on). If this malfunction occurs frequently, the compressor can only be switched on after erasing the DTC memory.
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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.
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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-
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01-42

Output Diagnostic Test Mode (DTM)
(function 03)


Function
Output DTM allows functional checking of A/C
control head actuated components (DTM
components). Actuators receive output signals
generated by the control head via VAG1551
Scan Tool (ST) in sequence. Function is
confirmed in accordance with specified
responses.
The following components are tested in
sequence using Output DTM:

1 - A/C Clutch -N25-

2 - Fresh Air Blower -V2-

3 - Coolant Fan -V7-

4 - Fresh Air/Recirculating Flap Two-Way Valve
-N63-1)

5 - Temperature Regulator Flap Motor -V68-

6 - Central Air Flap Motor -V70-
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7 - Footwell/Defroster Flap Motor -V85-

8 - Air Flow Flap Motor -V71-

9 - Interior Temperature Sensor Fan -V42-

10 - A/C control head display segment test

11 - Outside Air Temperature Display -G106-
test

1) Not installed on m.y. 1997 vehicles.
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01-43
Notes:

During Output DTM on vehicles with Control Head (E87) Part Number 8D0 820 043 D, A/C Compressor Clutch (N25) DTC
"01270, mechanical malfunction SP" may be stored even though no malfunction is present. Corrective action: When
output DTM is complete, check DTC memory. If above DTC is present, erase DTC memory.
When starting Output DTM, temperature and air distribution flap flap motors move to pre-determined positions in
preparation for individual tests: Temperature Regulator Flap Motor V68: moves to "heat" position. Central Air Flap Motor -
V70- moves to "floor & defroster outlet" position. Footwell Defroster Flap Motor V85 moves to "defrost" position.
Output DTM can be repeated several times, if necessary.
During Output DTM, vehicle must not be moved and engine speed must be less than 3000 rpm.
During Output DTM, A/C system control is switched off and all segments in both A/C control head displays are actuated.
Interior temperature sensor fan -V42- is activated via an A/C control head:
with one display after activation of the coolant fan.
with two displays after activation of air flow flap motor.
Outside air temperature display -G106- is activated via an A/C control head
with one display after activation of air flow flap motor.
with two displays after activation of idle regulation.
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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
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