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Basic setting of auxiliary heater > < Starting final control diagnosis

A4 Cabriolet Mk2

Control elements actuated
   
Control elements actuated
Indicated on display Specified functionFault rectification
Self-test
–  This test is implemented automatically; press → key without delay
The auxiliary heater control unit -J364- checks the connected components
–  No component actuation
–  Any faults detected are entered in the fault memory
 
Press → keyThe next component is displayed in the final control diagnosis.
–  Fault detected in self-test; interrogate fault memory → Chapter
Circulation pump -V55-Circulation pump -V55- is actuated.
–  Running noise is audible in vicinity of auxiliary heater.
–  Check wiring between circulation pump -V55- and auxiliary heater control unit -J364-.
–  Check auxiliary heater electrical components → Chapter.

  Note
t  At present, the circulation pump -V55- is not regulated by the auxiliary heater control unit -J364- but rather only switched on or off. At a later date, it is planned to install auxiliary heater control units -J364- which will regulate the delivery of the circulation pump -V55- as a function of the coolant temperature in the auxiliary heater (introduction not yet finalised).
t  To assist the engine coolant pump, the circulation pump -V55- can also be activated with the auxiliary heater switched off → Chapter.
t  With certain auxiliary heater control units -J364-, the “final control diagnosis” function results in storage of the fault circulation pump -V55- although there is no fault present and the circulation pump is functioning properly. In such cases, the fault memory is to be erased on completion of final control diagnosis.
   
Indicated on display Specified functionFault rectification
Press → key  
Combustion air blower -V6-Combustion air blower -V6- is actuated at approx. 50% of maximum speed.
–  Running noise is audible in vicinity of auxiliary heater.
–  Check wiring between combustion air blower -V6- and auxiliary heater control unit -J364-.
–  Check auxiliary heater electrical components → Chapter.
Press → key  
Glow plug for heater -Q9-Glow plug for heater -Q9- is actuated for 10 seconds.
–  The display on the measuring instrument (e.g. multimeter -V.A.G 1715-) increases during actuation of the glow plug for heater -Q9- by 6 to 14 A.
–  Check wiring between glow plug for heater -Q9- and auxiliary heater control unit -J364-.
–  Check earth connection between auxiliary heater and auxiliary heater control unit -J364- (stud at heater)
–  Check auxiliary heater electrical components → Chapter.

  Note
t  The current input of the glow plug for heater -Q9- is limited by the auxiliary heater control unit -J364- such that the power output at the glow plug during final control diagnosis is approx. 90 W. The auxiliary heater control unit -J364- actuates the glow plug for heater -Q9- at a frequency of 400 Hz (pulses per second) for power regulation.
t  As other vehicle components may be switched on in addition to the glow plug for heater -Q9-, attention is to be paid when performing this test to the increase in current during actuation.
t  Depending on the version of the auxiliary heater control unit -J364-, the display may not be glow plug for heater -Q9- but rather glow plug with flame monitor -Q8-.
   
Indicated on display Specified functionFault rectification
Press → key  
Metering pump -V54-Metering pump is actuated for 10 seconds.
–  Pulsation is audible in vicinity of metering pump.
–  Check wiring between metering pump -V54- and auxiliary heater control unit -J364-.
–  Check auxiliary heater electrical components → Chapter.

  Note
t  The metering pump -V54- is installed at the floor panel in front of the rear right wheel.
t  For vehicles on which the auxiliary heater is operated as supplementary heater (vehicles with diesel engine with no electric supplementary heater), the fuel consumption of the auxiliary heater (as supplementary heater with engine running) is incorporated into the consumption value displayed by the on-board computer.
t  During actuation of the metering pump -V54-, roughly 2 cm 3 of fuel is conveyed into the supplementary heater.
t  In auxiliary heating mode, the metering pump -V54- is actuated with full voltage by the auxiliary heater control unit -J364- up to control unit part number index “B”. For control units as of part number index “C” (gradual introduction as of Model Year 2005), the voltage for the actuation signal of the metering pump -V54- will be limited in auxiliary heating mode to 9.2 V with the petrol version and 9.8 V with the diesel version, thus reducing the operating noise of the metering pump -V54-.
t  Depending on the auxiliary heater version, the metering pump -V54- may no longer be actuated on repeating final control diagnosis. With these versions, renewed actuation is only possible after the auxiliary heater control unit -J364- has detected a flame in the auxiliary heater at least once.
  WARNING
Fuel is conveyed into the auxiliary heater when performing final control diagnosis. This function should therefore only be implemented once.
Should it be necessary to perform final control diagnosis several times in succession, unburnt fuel may accumulate in the auxiliary heater. This could cause fuel deflagration in the auxiliary heater when the auxiliary heater is switched on for the first time following final control diagnosis. On initial switch-on, particular care should therefore be taken to ensure that the auxiliary heater exhaust gas is routed directly into a suitable exhaust gas extractor and drawn off.
   
Indicated on display Specified functionFault rectification
Press → key  
Fresh air blower actuation signalThe operating and display unit, Climatronic control unit -J255- of the air conditioner/heater starts up.
The fresh air blower -V2- is actuated by the operating and display unit, Climatronic control unit -J255- at approx. 25% of the maximum possible speed.
–  Interrogate fault memory of operating and display unit, Climatronic control unit -J255- and eliminate cause of trouble. → Air conditioning; Rep. Gr.01 and → Heating; Rep. Gr.01.
–  Check encoding and adaption of control unit in dash panel insert -J285- and correct if necessary (adaption channels “18” and “61”). → Electrical system; Rep. Gr.01 and → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
Press → key  
This concludes the control element test (only for vehicles with no heater coolant shut-off valve -N279-, refer to next Section). 

  Note
t  The data for actuation of the operating and display unit, Climatronic control unit -J255- are transmitted by way of the convenience data bus system to the operating and display unit, Climatronic control unit -J255-.
t  In auxiliary heating mode, the operating and display unit, Climatronic control unit -J255- is actuated as soon as the coolant temperature in the auxiliary heater exceeds approx. 45 °C.
   
Indicated on display Specified functionFault rectification
Heater coolant shut-off valve -N279-The heater coolant shut-off valve -N279- is actuated by way of the auxiliary heater control unit -J364- at 1 second intervals.
–  Pulsation is audible in vicinity of shut-off valve.
–  Check wiring between heater coolant shut-off valve -N279- and auxiliary heater control unit -J364-.
–  Check encoding of auxiliary heater control unit -J364- → Chapter
–  Check supplementary heater electrical components → Chapter.
Press → key  
Control element test over 

  Note
t  In auxiliary heating mode with the engine stopped, the coolant is routed via the heater coolant shut-off valve -N279- directly back from the heat exchanger (of the air conditioner unit/heater) to the auxiliary heater (small coolant circuit), thus enhancing passenger compartment heating. Actuation of the heater coolant shut-off valve -N279- is regulated by the auxiliary heater control unit -J364- by way of the measured coolant temperature in the auxiliary heater and the setting received in the dash panel insert via the convenience data bus system (heating of engine in auxiliary heating mode yes/no).
t  To enhance comfort, the heater coolant shut-off valve -N279- is also actuated for example if the engine is started during the warm-up phase in auxiliary heating mode (small coolant circuit) and the cold coolant from the engine causes the coolant temperature in the auxiliary heater to decrease.
t  For vehicles with diesel engine on which the auxiliary heater is actuated as supplementary heater, the auxiliary heater control unit -J364- can also actuate the heater coolant shut-off valve -N279- in supplementary heating mode to provide better passenger compartment heating with a low coolant temperature.
t  On vehicles with 4-cyl. engine, the heater coolant shut-off valve -N279- is not actuated at present. Vehicles manufactured up to Model Year 2004 may be fitted with a shut-off valve, but this is not actuated (the auxiliary heater control unit -J364- must be encoded accordingly).
t  At the start of production (up to Model Year 2004), vehicles with 4-cyl. engine were fitted with the heater coolant shut-off valve -N279-. However, in view of the fact that cold starting problems may be encountered with these engines at very low ambient temperatures following auxiliary heating operation with a small coolant circuit (engine is only slightly pre-heated), the auxiliary heater control unit -J364- is to be encoded such that the heater coolant shut-off valve -N279- is not actuated.
   

Basic setting of auxiliary heater > < Starting final control diagnosis