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Speed signal: check > < Speed signal: check

Leon Mk2

Signals from/to the air conditioning: check
Signals from/to the air conditioning: check
Special tools and workshop equipment required
t  Fault reader -V.A.G 1551- or vehicle system checker -V.A.G 1552- with cable -V.A.G 1551/3B-
t  Checking box -V.A.G 1598/22-
t  Manual multimeter -V.A.G 1526 A- or multimeter -V.A.G 1715-
t  Auxiliary measuring set -V.A.G 1594 C-
t  Current circuit diagrams
Checking conditions
l  Working of the air conditioning, correct.
l  There should be no fault recorded in the memory → Chapter, Fault memory: consult.
l  The vehicle must be at room temperature (over +15_C).
l  Air conditioning open.
Make sure the air conditioning compressor turns off
Through the signal from the air conditioning compressor, the control and indication panel informs the engine control unit that the compressor will soon be coming on.
Through this same cabling connection, the engine control unit disconnects the air conditioning compressor under the following conditions:
t  On accelerating hard from low speed.
t  In the emergency program (emergency Running operative mode).
t  If the coolant has a temperature of over +120 °C.
t  For some 6 seconds after each start.
Checking process
–  Connect the -V.A.G 1551- (-V.A.G 1552-), and using the corresponding “direction code” 01, select the control unit for engine electronics. When doing this, the engine must be idling: (Fault reader: Turn on and select the control unit for engine electronics → Chapter).
–  Turn on the air conditioning.
–  Select the lowest temperature and the maximum turbine speed. The compressor should work.
   
Indication on the display:
–  Press the keys 0 and 3 for the function “Actuator diagnosis”.
  
Fast data transmission              HELP
Select the function XX
Indication on the display:
–  Confirm the entry with Q.
  
Fast data transmission                 Q
03-Actuator diagnosis
Indication on the display:
–  Press →.
  
Actuator element diagnosis            ->
Injection start valve N108
Indication on the display:
–  Press →.
  
Actuator element diagnosis            ->
Exhaust gas recirc. valve N18
Indication on the display:
It is made sure that the air conditioning compressor turns off.
The air conditioning compressor must be stopped within 5 seconds (visual examination) and then started every 5 seconds and stopped again.
If the air conditioning compressor fails to turn off:
–  Continue the actuator diagnosis until the end.
–  Press the keys 0 and 6 for the function “End data transmission” and confirm with Q.
–  Turn off the ignition.
  
Actuator element diagnosis            ->
Intervention of air conditioning
–  Connect the -V.A.G 1598/22- checking box to the cable harness of the control unit.
–  Check for breakage in the cable between the checking box female 16 and the air conditioning, following the current circuit diagram → Current flow diagrams, Electrical fault finding and Fitting locations
Cable resistance: 1,5Ω max.
Check the air conditioning signal for the adaptation of the engine speed
The signal makes the engine control unit hold the idle speed constant, even when the air conditioning demands power deliveries of different magnitudes.
Checking process
–  Connect the -V.A.G 1551- (-V.A.G 1552-), and using the corresponding “direction code” 01, select the control unit for engine electronics. When doing this, the engine must be idling: (Fault reader: Turn on and select the control unit for engine electronics → Chapter).
  N24-0709
Indication on the display:
–  Press the keys 0 and 8 for the function “Read measurement value block” and confirm with Q.
  
Fast data transmission              HELP
Select the function XX
Indication on the display:
–  Press the keys00 and 2 for “Indication group number 2” and confirm with Q.
  
Read measurement value block            
Enter value group number XXX
–  Observe the indication in field 3:
Theoretical value 0 1 0
–  Turn on the air conditioning.
–  Set the lowest temperature and the maximum turbine speed.
  
Read measurement value block 2        ->
900 U/min      0,0%     0 1 0    87,3 °C
–  Observe the indication in field 3:
Theoretical value 0 1 1(signal from the air conditioning)
–  Press →.
–  Press keys 0 and 6 for the function “End data transmission” and confirm with Q.
–  Turn off the ignition.
If the theoretical value is not reached:
  
Read measurement value block 2        ->
900 U/min     0,0%      0 1 1    87,7 °C
–  Connect the -V.A.G 1598/22- checking box to the cable harness of the control unit.
–  Check for breakage in the cable between the checking box female 48 and the air conditioning, following the current circuit diagram → Current flow diagrams, Electrical fault finding and Fitting locations.
   Cable resistance: 1,5Ω max.
  N24-0709

Speed signal: check > < Speed signal: check