coolant temperature AUDI A4 2000 B5 / 1.G Instrument Cluster OBD From Model Year 1999 Workshop Manual

01-1


Instrument cluster, On Board
Diagnostic (OBD) (through
M.Y. 1999)

General information


Instrument cluster technology
The Audi A4 instrument cluster is available in two
versions; the low-line version with "mini-check"
system and the high-line version with an LCD
multi-function display.
The mini-check system monitors the brake
system, Engine Coolant Temperature (ECT), fuel
level and engine oil pressure.
The multi-function display contains the following
functions:

Auto check system with radio station and
telephone displays
Ambient outside temperature display
On-board computer display
Transmission Range (TR) selector lever display
for automatic transmission
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01-12
Diagnostic Trouble Code (DTC) table for instrument cluster

Notes:

The following table lists all possible Diagnostic Trouble Codes (DTCs) which the instrument cluster can recognize and
which the VAG1551 scan tool can print.
DTC numbers only appear on the printout.
Before replacing any component shown as malfunctioning, check all related wiring and connections of these components
and the Ground (GND) connections Electrical Wiring Diagrams Troubleshooting & Component Locations After the repair has been carried out and the functional system check, re-check and erase the DTC memory using the
VAG1551 scan tool.
The DTC memory records all static and sporadic (intermittent) malfunctions. A malfunction is considered static if it exists
for at least 2 seconds (exceptions: 60 seconds for outside temperature display and 30 minutes, for engine coolant sensor).
If the malfunction is not present after this time, it will be stored as a sporadic DTC and "/SP" will appear on the right side of
the scan tool display.
After switching the ignition on, all existing DTCs are set to sporadic. If they are still present after the system check, they
will be stored as static DTCs.
If a sporadic malfunction does not reoccur within 50 driving cycles (ignition on for at least 5 minutes and vehicle speed
greater than 30 km/h or 18 mph), it will be erased.
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01-14

01039
ECT Sensor-G2

Open/Short
circuit to B+
Short circuit to
Ground (GND)
Open circuit or short circuit between Engine Coolant
Temperature Sensor (ECT) -G2- and instrument
cluster
ECT sensor -G2- faulty- Trace malfunction Electrical Wiring
Diagrams, Troubleshooting & Component
Locations
- Replace -G2-.
01402
Data Wire from
Navigation

Incorrect signal
Open circuit in clock enable or data wire
Navigation/instrument cluster interface
malfunctioning
Malfunction caused by electromagnetic interference
inside and outside vehicle Repair Manual Radio, Telephone,
Navigation, Repair Group 97 - Check data wire for damage.
- Check causes for electromagnetic
malfunctions.
65535
Control Module
Malfunctioning
Instrument cluster faulty- Replace instrument cluster Page 90
-
1 .
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01-15

Output Diagnostic Test Mode (scan tool
function 03)


Notes:

Output Diagnostic Test Mode may only be
carried out on a stationary vehicle with the
engine off.
Trace any faults identified by the Output
Diagnostic Test Mode, replace the instrument
cluster if necessary.

The function "Output Diagnostic Test Mode"
cycles all the control elements in the
instrument cluster sequentially, if they are
installed and coded.
Concurrent testing of the display ranges of all
the analog indicators (coolant temperature
gauge, tachometer, speedometer and fuel
gauge).
Activation of the mini-check indicator lights.
Activation of the seat belt warning lamp.
Activation of the chime.
Pa
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Segment check of the multi-function display
and/or the LCD odometer.
Activation of the instrument cluster lights and
dimmer.
Coolant excess temperature test
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01-16

Notes:

The instrument cluster lighting test can only be
carried out with the lights on.
The coolant excess temperature test activates
the A/C compressor safety shut-off.

Initiating Output Diagnostic Test Mode

Note:
The units displayed are country specific.
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -3- to select "Output Diagnostic Test Mode"
function 03.
Rapid data transfer
Q
03 - Output Diagnostic Test Mode

Indicated on display
- Press -Q- button to confirm input.
This will start the Output Diagnostic Test Mode for the analog
instruments (displays).
Output Diagnostic Test Mode Analog Indicators

Indicated on display
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01-17
After pressing the -Q- button, the following tests
are run:

Coolant temperature gauge needle moves over
complete range
Tachometer needle moves over complete
range
Speedometer needle moves over complete
range
Fuel gauge needle moves over complete
range
The following preset values are displayed at the
end of the test:

Coolant temperature
display: 90 C (194 F)
Tachometer: 3000 RPM
Speedometer: 100 km/h (62
mph)
Fuel level: 1/2

Note:
If the ignition is switched on or off with any gauge
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01-28

Display group overview

Display
group Indicated on display
001 1 = Vehicle speed (kmh/MPH)
2 = Engine speed (RPM)
3 = Oil pressure switch 2 < min
002 1 = Odometer (km/mi)
2 = Fuel gauge (liters/gal)
3 = Outside temperature ( C/F) 003 1 = Engine coolant temperature (
C/F) 050 1 = Odometer (km/mi)
2 = Engine speed (RPM)
4 = Engine coolant temperature (
C/F)

Notes:

The display will always show the actual values
from the sensors. Since the instrument panel
displays filters the values, they may differ from
the actual values.
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If the actual Engine Coolant Temperature (ECT)
is between 80 C (176 F) and 100 C (212 F),
the instrument panel will always display 90 C
(194 F).

Additional display groups for the instrument
cluster are not possible.
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Coolant temperature

50 to 130 C


Pa
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yp
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