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Throttle valve control part checking > < Lambda probe heating before catalytic converter checking

Leon Mk2

Lambda probe heating after catalytic converter checking
Lambda probe heating after catalytic converter 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
Check conditions
l  Fuses no. 15 and 18, OK.
l  Battery voltage at least 11.5 V.
l  Fuel pump relay must be OK.
Test sequence
–  Connect fault reader -V.A.G 1551/V.A.G 1552-. Start engine and select “Address code” 01 of engine control unit. (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, 4 and 1 for “Display group number 41” and confirm entry with Q -key.
  
Read measured value block           HELP
Input display group number XXX
Indicated on display: (1...4 = Display fields)
–  Check the status of the Lambda probe heating before catalytic converter in display field 4:
   Display: Htg. aC. ON
  Note!
Lambda probe heating is switched on and off depending on engine load, so the reading in display field 4 can be Htg. aC. ON or alternate between Htg. aC. ON and Htg. aC. OFF.
If the specification is not obtained:
  
Read measured value block          41 ->
         1         2         3         4
–  Unplug 4-pin connector to Lambda probe after catalytic converter -G130--arrow-.
  E24-0073
–  Check probe heating for continuity at Lambda probe connector contacts 1 and 2.
  Note!
At room temperature the heater element resistance is approx. 1...5 Ω. Even slight increases in temperature increase the resistance greatly.
If it is determined that probe heating has an open circuit:
–  Renew Lambda probe after catalytic converter -G130-.
If probe heating has continuity:
Checking voltage supply
  N24-0721
–  Switch multimeter to voltage test and connect it to contacts 1+2 of connector to engine control unit with aux. cables from -V.A.G 1594 C-.
–  Start engine and run at idling speed.
–  Measure voltage supply and observe display group 41, display field 4:
Display Htg. aC. ON:
   Specification: 11.0...14.5 V
Reading Htg. aC. ON/Htg. aC. OFF (alternating)
   Specification: oscillates between 0.0...12.0 V
–  Press → -key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q -key.
–  Switch off ignition.
If no voltage is present:
  N24-0722
–  Connect test box -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.
  N24-0943
–  Check 4-pin connector between contact 2 and socket 63 for open circuit.
   Wire resistance: max. 1.5 Ω
If the specification is obtained:
–  Check wiring between 4-pin connector contact 1 and fuel pump relay -J17- for open circuit using current flow diagram.
   Wire resistance: max. 1.5 Ω
  N24-0723

Throttle valve control part checking > < Lambda probe heating before catalytic converter checking