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Engine control unit > < Checking ageing of Lambda probe before catalyst

Leon Mk2

Checking engine operating mode
Checking engine operating mode
  Note!
Checks whether engine control unit recognises the engine operating modes idling, overrun, part throttle, enrichment, full throttle.
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 1551/3A-
Test conditions
l  Coolant temperature must be at least 80 °C, ⇒ display group 04, display zone 3.
Test sequence
–  Connect fault reader -V.A.G 1551- (-V.A.G 1552-). Start engine and select “Address word” 01 of engine control unit. When doing this the engine must be running at idling speed. (Connecting fault reader and selecting engine control unit → Vehicle diagnosis, testing and information system VAS 5051.)
   
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 5 for “Display group number 5” and confirm entry with Q key.
  
Read measured value block               
Input display group number XXX
Indicated on display: (1...4 = Display zones)
–  Check whether the control unit recognises the operating mode (display zone 4):
t  Idling:
As long as the engine is running at idling speed idling must be displayed Display: Idling
t  Overrun mode:
–  Increase engine speed to above 3000 rpm.
–  Close throttle abruptly.
As long as the engine speed is above 1400 rpm overrun must be displayed Display: Overrun
  Note!
Below 1400 rpm idling speed will be recognised.
t  Part throttle:
–  Rev up evenly.
As long as the engine is being revved up evenly, part throttle must be displayed Display: Part throt.
t  Enrichment:
–  Floor accelerator pedal (onto throttle valve stop).
Acceleration enrichment must be displayed briefly Display: Enrichment
t  Full throttle:
–  Floor accelerator pedal (onto throttle valve stop).
Full throttle must be displayed briefly Display: Full throttle
  Note!
A test drive may have to be performed to show “Full throttle” in display.
Observe the valid safety precautions when carrying out a road test → Chapter.
–  Press → key.
–  Press keys 0 and 6 for the function “End output” and confirm entry with the Q key.
If the specifications are not attained:
–  Interrogate fault memory, if necessary, repair any faults and then erase fault memory → Vehicle diagnosis, testing and information system VAS 5051, interrogating and erasing fault memory.
–  Check throttle valve control part → Chapter.
–  Check parts of the electronic throttle control (EPC) for ease of movement: → Chapter
  
Read measured value block 5            →

      

      

    


Engine control unit >
< Checking ageing of Lambda probe before catalyst