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

01-5

Notes:

For m.y. 1997, changes that affect monitoring of
the A/C system by A/C control head -E87- were
made.
Monitored components, locations pages 87
-
101
and Page 87
-113
.

Additional technical data and notes page 01
-
1 .

If a replacement A/C control head is not coded
after installation or if an unrecognized code was
entered, code "04142" (Audi A4 -4cyl. -USA) is
stored.
The A/C control head is no longer connected to
terminal 30 (vehicle electronics). The last input
setting (into the A/C control head) is stored
when the ignition is switched off and retained
when the ignition is switched on.
The duration of time when ignition is off is
calculated by the A/C control head. When
ignition is switched on, the previous "standing
time" is calculated by monitoring a time signal
from the instrument cluster. If more than 4
hours pass since ignition was switched off, the
actual measured values of the outside
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The fresh air blower and control module.
Following components that provide input signals
to the A/C control head -E87- are revised:
Instrument cluster
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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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01-27

VAG1551 scan tool
display Possible cause
Corrective action
00604
Back Pressure Flap
Motor Position Sensor
G113 in Air Flow Flap
Motor V71

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 -
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
flap2)
- Replace -V71-
00625
Road speed signal

Implausible signal /SP - Loose terminal in wiring/connections between
Speedometer Vehicle Speed Sensor (VSS) G22, the
instrument cluster or in another component also
connected to this signal (e.g. radio or control module for
cruise control) and -E87-
- Speedometer -G21- or instrument cluster supplying
unusable signal or a component disrupts signal - Diagnose and repair loose terminal
using wiring diagram.





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- Test road speed signal from
Speedometer G21 or from instrument
cluster (check all components
connected to this circuit using wiring
diagram)
1)This DTC only recognized during basic setting.
2)Both end stops must be reached.
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01-37

VAG1551 Scan Tool display
Possible cause
Corrective action
01582
Coolant Temperature Signal
Short circuit or open circuit between
instrument cluster and A/C control head -
E87- - Locate short circuit or open circuit
according to wiring diagram and repair
Short circuit to
Ground /SP
Open/Short circuit
to B+ /SP
Incorrect
Signal /SP Instrument cluster malfunctioning- Check signal from instrument cluster.
Note:
The DTC "Coolant Temperature Signal" is only recognized by A/C control heads -E87- with one display.
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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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e=re
pair&id=AUDI.B5.HA01.01.1