Function - Audi A3 1997 Manual

Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000

1.3 - Function

Air conditioner control and display unit -E87 (control unit) receives information from electrical and electronic
components (signal senders) and then processes this information according to the programmed specified val‐
ues.
The output signals of the control unit then regulate the electrical components (control elements).
To enable the cause of the problem to be established quickly in the event of a component failure or open circuit
in wiring, operating and display unit -E87 is equipped with a fault memory which can be read with fault reader
V.A.G 1551, vehicle diagnosis system VAS 5051 or vehicle system tester V.A.G 1552.
If faults occur in the monitored sensors and components, these are stored in the fault memory together with an
indication of type of fault.
Always commence fault finding by starting self-diagnosis and interrogating the stored information with
fault reader V.A.G 1551
vehicle system tester V.A.G 1552,
or
vehicle diagnostic, measuring and information system VAS 5051.
The fault information which is displayed indicates specific repair measures via a fault table.
Notes on fault remedy:
◆ Data output is only possible with the ignition switched on or with the engine running and an engine speed
of less than 3000 rpm. At higher engine speeds, data output is restricted or terminated (for example, final
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control diagnosis can only be implemented up to an engine speed of 3000 rpm; if this speed is exceeded,
self-diagnosis is terminated).
◆ If a fault situation exists for longer than a specific period, the fault is stored as a static fault. If the fault is no
longer present after a specified period, it becomes a sporadic fault. This process is constantly repeated.
Sporadic faults are also identified as such (the letters /SP appear on the display).
◆ If a sporadic fault ceases to occur for a specific period, it is automatically erased.
The possibilities offered by self-diagnosis can only be utilised by employing fault reader V.A.G 1551 (mode 1,
"Rapid data transfer"), V.A.G 1552, or VAS 5051.
Self-diagnosis is not restricted to storage, interrogation, erasing and final control diagnosis. It also has basic
setting, control unit identification and encoding functions.
Mode -2- (flash code output) is not envisaged for electronic climate/heating control. Modes -3- (self-test) and
-4- (dealership identification) only apply to fault reader V.A.G 1551 and vehicle system tester V.A.G 1552 and
are described in the appropriate manuals.
Note:
The following describes self-diagnosis using the fault reader V.A.G 1551 only.
Self-diagnosis can also be performed in the same manner with VAS 5051 or V.A.G 1552. In order to be able
to provide proof of faults in the event of subsequent queries, it is advisable to print out any faults found after
interrogating the fault memory.
If the fault memory has been read out using V.A.G 1552, before erasing the fault memory, connect V.A.G 1551
or VAS 5051 and print out the faults found (V.A.G 1552 does not have a printer).
2
01 - Self-diagnosis, Electrical check
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