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Engine revs sender: testing > < Intake air temperature sender: testing

Leon Mk2

Coolant temperature sender: testing
   
Coolant temperature sender: testing
Special tools and workshop equipment required
t  Fault reader -V.A.G 1551- or Vehicle systems checker -V.A.G 1552- with Lead -V.A.G 1551/3B-
t  Test box -V.A.G 1598/22-
t  Hand-held multimeter -V.A.G 1526 A- or Multimeter -V.A.G 1715-
t  Auxiliary measurement set -V.A.G 1594 C-
t  Wiring diagram

Test condition
l  The engine must be cold.
Test process
–  Connect the -V.A.G 1551- (V.A.G. 1552). Switch on the ignition and enter “address code” 01 to select the engine control unit. (Fault reader: Connecting and selecting the engine control unit → Chapter.).
   
The display reads:
–  Press 0 and 8 for the function “Read measurement value block” and press Q to confirm the entry.
  
Rapid data transmission             HELP
Select function XX
The display reads:
–  Press 0, 0 and 4 for “Display group number 4” and press Q to confirm the entry.
  
Read measurement value block        HELP
Enter display group number XXX
The display reads: (1...4 = display fields)
–  Read the coolant temperature value displayed in field 3.
–  Continue the test according to the following table:
  
Read measurement value block     4    ->
         1         2         3         4
Displayed valueCauseContinue test
Approx. coolant temperature → Note---Only in event of display of sporadic fault → Note → Anchor
-40 °COpen circuit or short circuit to positive → Anchor
129 °CShort circuit to earth → Anchor

1)  f the display shows a temperature that differs significantly from sender ambient temperature, test the sender wiring for contact resistances.
2)  The test is only possible when the engine is cold.
If the display shows the coolant temperature, continue the test as follows:
Function test of the sender
–  Connect the -V.A.G 1551- (V.A.G. 1552). Start the engine and enter “address code” 01 to select the engine control unit. (Fault reader: Connecting and selecting the engine control unit → Chapter.).
   
The display reads:
–  Press 0 and 8 for the function “Read measurement value block” and press Q to confirm the entry.
  
Rapid data transmission             HELP
Select function XX
The display reads:
–  Press 0, 0 and 4 for “Display group number 4” and press Q to confirm the entry.
  
Read measurement value block        HELP
Enter display group number XXX
The display reads: (1...4 = display fields)
–  Read the coolant temperature value displayed in field 3 with the engine running. The temperature value should rise steadily.
  Note!
t  The temperature rises from 1.0 °C to 1.0 °C.
t  Within a certain temperature range, if engine performance is faulty and the temperature value does not rise steadily, that means that there are transient interruptions in the temperature signal and the sender must be replaced.
–  Press →.
–  Press 0 and 6 for the function “End data transmission” and press Q to confirm the entry.
–  Switch off the ignition.
If the target value is not reached:
–  Remove the air filter → Fig.
–  Replace the coolant temperature sender -G62- with coolant temperature indicator sender -G2- → Item.
If the display reads -40 °C, continue the test as follows:
–  Remove the air filter → Fig.
  
Read measurement value block     4    ->
         1         2         3         4
–  Unplug the 4-pin connector from the coolant temperature sender -G62- with coolant temperature indicator sender -G2--arrow-.
  N24-1080
–  Bridge connector contacts 3+4 with auxiliary leads -V.A.G 1594 C- and check the values on the display.
If the displayed value jumps to 129 °C:
–  Press →.
–  Press 0 and 6 for the function “End data transmission” and press Q to confirm the entry.
–  Switch off the ignition.
–  Replace the coolant temperature sender -G62- with coolant temperature indicator sender -G2- → Item.
If the displayed value holds at -40 °C:
–  Press →.
–  Press 0 and 6 for the function “End data transmission” and press Q to confirm the entry.
–  Switch off the ignition.
  N24-1040
–  Connect test box -V.A.G 1598/22- to the control unit wiring harness.
  N24-0709
–  Test for open circuits in the wiring between the test box and the 4-pin connector (connector to the control unit) following the wiring diagram.
   Contact 3+female contact 74
   Contact 4+female contact 54
Wiring resistance: 1.5 Ω∼max
–  Test the wire for short circuit to battery positive. Target value: ∞ Ω
If no fault is found in the wiring:
–  Replace the coolant temperature sender -G62- with coolant temperature indicator sender -G2- → Item.
If the display reads 129 °C, continue the test as follows:
–  Remove the air filter → Fig.
  N24-1040
–  Unplug the 4-pin connector from the coolant temperature sender -G62- with coolant temperature indicator sender -G2--arrow-.
If the displayed value jumps to -40 °C:
–  Press →.
–  Press 0 and 6 for the function “End data transmission” and press Q to confirm the entry.
–  Switch off the ignition.
–  Replace the coolant temperature sender -G62- with coolant temperature indicator sender -G2- → Item.
If the display reads 129 °C:
–  Press →.
–  Press 0 and 6 for the function “End data transmission” and press Q to confirm the entry.
–  Switch off the ignition.
  N24-1080
–  Connect test box -V.A.G 1598/22- to the control unit wiring harness.
  N24-0709
–  Test for open circuits in the wiring between the test box and the 4-pin connector (connector to the control unit) following the wiring diagram.
   Contact 3+female contact 74
   Contact 4+female contact 54
Wiring resistance: 1.5 Ω∼max.
–  Test the wire for short circuit to battery positive. Target value: ∞ Ω
If no fault is found in the wiring:
–  Replace the coolant temperature sender -G62- with coolant temperature indicator sender -G2- → Item.
  N24-1040

Engine revs sender: testing > < Intake air temperature sender: testing