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Engine speed sender: checking > < Intake air temperature sender checking

Leon Mk2

Coolant temperature sender checking
Coolant temperature sender checking
Special tools and workshop equipment required
t  Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3B-
t  Test box -V.A.G 1598/31-
t  Hand multimeter -V.A.G 1526 A- or multimeter -V.A.G 1715-
t  Adapter set -V.A.G 1594 C-
t  Current flow diagram
Test sequence
–  Connect fault reader -V.A.G 1551/V.A.G 1552-. Then switch ignition on and select engine control unit with the “Address code” 01. (Fault reader: Connecting and selecting the engine control unit → Chapter).
   
Indicated on display:
–  Press keys 0 and 8 for the function “Read measured value block” and confirm entry with Q -key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press keys 0, 0 and 1 for “Display group number 1” and confirm entry with Q -key.
  
Read measured value block           HELP
Input display group number XXX
Indicated on display: (1...4 = Display fields)
–  Note coolant temperature value in display field 2.
–  If the specification is not obtained:
–  Perform check according to following table:
  
Read measured value block           1 ->
         1         2         3         4
DisplayCauseContinuation of check
-40°COpen circuit or short to positive →  
120°CShort to earth →  
Approx. coolant temperature → Note---Only if sporadic faults have been detected: → Note → 

1)  If a temperature is displayed which deviates greatly from the ambient temperature of the sender, check sender wiring for transfer resistances.
2)  Check is only possible when the engine is cold.
Continuation of check when display shows -40 °C:
   
–  Pull the 4-pin connector off coolant temperature sender -G62- with coolant temperature gauge sender -G2--arrow-.
  N24-1053
–  Bridge connector contacts 3+4 using aux. cables from -V.A.G 1594 C- and observe display.
If the display changes to 120 °C:
–  Press → -key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q -key.
–  Switch off ignition.
–  Replace coolant temperature sender -G62- with coolant temperature gauge sender -G2- → Item.
If the display remains at -40 °C:
–  Press → -key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q -key.
–  Switch off ignition.
  N24-1040
–  Connect test box -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.
  N24-0943
–  Check the wiring between test box and 4-pin connector for open circuit using current flow diagram.
   Contact 3+socket 93
   Contact 4+socket 108
   Wire resistance: max. 1.5 Ω
–  Check wiring additionally for short circuit to battery positive.
   Specification: ∞ Ω
If no wiring fault is detected:
–  Replace coolant temperature sender -G62- with coolant temperature gauge sender -G2- → Item.
Continuation of check when display shows 120 °C:
  N24-1040
–  Pull the 4-pin connector off coolant temperature sender -G62- with coolant temperature gauge sender -G2--arrow-.
If the display changes to -40 °C:
–  Press → -key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q -key.
–  Switch off ignition.
–  Replace coolant temperature sender -G62- with coolant temperature gauge sender -G2- → Item.
If the display remains at 120 °C:
–  Press → -key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q -key.
–  Switch off ignition.
  N24-1053
–  Connect test box -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.
  N24-0943
–  Check the wiring between test box and 4-pin connector for open circuit using current flow diagram.
   Contact 3+socket 93
   Contact 4+socket 108
   Wire resistance: max. 1.5 Ω
–  Check wiring additionally for short circuit to battery positive.
   Specification ∞ Ω
If no wiring fault is detected:
–  Replace coolant temperature sender -G62- with coolant temperature gauge sender -G2- → Item.
Continuation of check when display = coolant temperature:
Test conditions
l  Engine must be cold.
Functional check of sender:
–  Connect fault reader -V.A.G 1551/V.A.G 1552-. Start engine and select “Address code” 01 of engine control unit. When doing this the engine must be running at idling speed. (Fault reader: Connecting and selecting the engine control unit → Chapter).
  N24-1040
Indicated on display:
–  Press keys 0 and 8 for the function “Read measured value block” and confirm entry with Q -key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press keys 0, 0 and 1 for “Display group number 1” and confirm entry with Q -key.
  
Read measured value block           HELP
Input display group number XXX
Indicated on display: (1...4 = Display fields)
–  Observe coolant temperature value in display field 2. The value should rise steadily.
  Note!
t  If the value on the fault reader jumps from 2...5 °C: the cause is in the control unit, and is not due to a faulty sender.
t  If irregular engine running occurs in certain temperature ranges and the temperature figure does not increase without interruption, the temperature signal is temporarily interrupted and the sender must be renewed.
–  Press → -key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q -key.
–  Switch off ignition.
If the specification is not obtained:
–  Replace coolant temperature sender -G62- with coolant temperature gauge sender -G2- → Item.
  
Read measured value block           1 ->
         1         2         3         4

Engine speed sender: checking > < Intake air temperature sender checking