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Lambda probe heating: checking > < Checking components

Leon Mk2

Checking Lambda probe and Lambda control: checking
   
Checking Lambda probe and Lambda control: checking
Special tools and workshop equipment required
t  Hand multimeter -V.A.G 1526 A- or multimeter -V.A.G 1715-
t  Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3B-
t  Auxiliary measuring set -V.A.G 1594 C-
t  Test box -V.A.G 1598/18-
t  Current flow diagram

Checking conditions
l  Idling adjustment, OK.
l  Exhaust system between cylinder head and catalytic converter free of leaks.
Checking process
–  Connect fault reader -V.A.G 1551- (-V.A.G 1552-). Start engine and enter “address code” 01 to select engine control unit. (Fault reader: Connecting and selecting the engine control unit → Chapter.)
   
Indicated on the display:
–  Press keys 0 and 8 for the function “Read measured value block” and confirm entry with the Q key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on the display:
–  Press keys 0, 0 and 1 for “Display group number 1” and confirm entry with the Q key.
  
Read measured value block           HELP
Input display group number XXX
Indicated on the display: (1…4 = display zones)
Only continue with the test when:
l  Coolant temperature above 80 °C -Display zone 2-.
l  Subsequently, the engine has then run for 2 more minutes at idling speed.
–  Observe Lambda probe voltage in display zone 3. The voltage should fluctuate at least 30 times per minute in a range of 0…1.0 V
If the voltage change is slower, determine cause of fault → .
  
Read measured value block 1           ->
         1         2         3         4
v
–  Plug in the connector again. The voltage of the probe should be decrease and rise again to the former regulation level.
  Note!
Do not action the throttle while during the check or the control unit will interpret the removed connector as a fault.
–  Press the → key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q key.
–  Switch ignition off.
If no regulation is found:
–  Check Lambda probe heating → Chapter.
  N24-0147
–  Connect test box -V.A.G 1598/18- to control unit wiring harness.
  N24-0334
–  Separate 4-pin connector to Lambda probe -G39--1-.
–  Check wiring for open circuit between test box and connector using current flow diagram.
  N24-0156
ContactTest box -V.A.G 1598/18-, socket
315
438
Wire resistance: 1,5 Ω max.

–  PCheck wiring at connector contacts 3+4 for short circuit to contacts 1+2 according to current flow diagram.
   Specification: ∞ Ω
If no wiring fault is detected:
–  Replace Lambda probe → Item.
Possible causes of fault if probe control frequency is too slow:
t  The slots or holes in probe body are blocked
t  The vent hole in probe -area of connecting wire- is blocked
t  The probe has been overheated (glazed)
t  The probe has been damaged by leaded fuel
   

Lambda probe heating: checking > < Checking components