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Skoda Workshop Service and Repair Manuals

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Testing the speed signal > < Testing auxiliary signals

Fabia Mk1

Testing signals from the air conditioning system
Testing signals from the air conditioning system
The air conditioning system is connected to the diesel direct injection system control unit -J248- via the data BUS. All signals of the air conditioning system from or to the diesel direct injection system control unit -J248- to the air conditioning system are transmitted via the data BUS.
Testing occurs via the measured value blocks of the air conditioning system and diesel direct injection system control unit - J248-.
Special tools and workshop equipment required
t  Vehicle system tester -V.A.G 1552-
t  Diagnostic cable -V.A.G 1551/3-
Test condition
l  No data bus fault → Electrical System; Rep. Gr.90
Test sequence
–  Connect vehicle system tester - V.A.G 1552-. Leave the engine on and select the engine control unit with “Address word” 01 → Chapter.
–  Select function 08 “read measured value block” and display group number 002.
   
–  Readout on display:
The air conditioning system is disconnected.
–  Observe display field 3.
   Specified value: 0 1 0
–  Switch on the air conditioning system.
–  Observe display field 3.
   Specified value: 1 1 1
  
Reading measured value block         2   ->
900/min       0.0%      010       90.0°C
Meaning, if display positions = 1 
XXXOperating position 
  1Air conditioning on 
 1 Idling switch closed (accelerator pedal not pressed)
1  Speed increase with AC system on

–  Switch off the air conditioning system.
–  Press key C.
–  Select display group number 021
   
–  Readout on display:
The air conditioning system is disconnected.
–  Observe display field 4.
   Specified value: 010000
–  Switch on the air conditioning system.
   Specified value: 111000.
–  If the display does not occur as described:
–  Test the air conditioning system → Heating, Air Conditioning; Rep. Gr.01
–  Test the data BUS. → Electrical System; Rep. Gr.90
  
Reading measured value block         21   ->
                                  010000

Testing the speed signal > < Testing auxiliary signals