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Checking intake manifold pressure sender > < Checking Lambda probe heating after catalyst

Leon Mk2

Checking throttle valve control part
Checking throttle valve control part
Components of throttle valve control part -J338-: Throttle valve drive -G186-, angle sender 1 for throttle valve drive -G187- and angle sender 2 for throttle valve drive -G188-.
  Note!
If the throttle valve control part is replaced, the new control part must without fail be adapted to the engine control unit → Chapter.
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-
t  Test box -V.A.G 1598/22-
t  Hand multimeter -V.A.G 1526- or multimeter -V.A.G 1715-
t  Adapter set -V.A.G 1594-
t  Current flow diagram
Check conditions
l  Throttle valve not damaged or dirty.
l  Coolant temperature must be at least 80 °C, ⇒ display group 04, display zone 3.
Test sequence
–  Connect the fault reader -V.A.G 1551- (-V.A.G 1552-). Then switch ignition on and select engine control unit with the “Address word” 01. (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, 6 and 2 for the “Display group number 62” and confirm entry with Q key.
  
Read measured value block               
Input display group number XXX
Indicated on display: (1...4 = Display zones)
–  Check throttle valve angle at idling stop from sender 1 -G187- in display zone 1 Specification: 10...90 %
–  Check throttle valve at idling stop from sender 2 -G188- in display zone 2. Specification: 90...10 %
–  Depress accelerator slowly to full throttle position and observe angles displayed in display zones 1 and 2:
The percentage figure in display zone 1 must increase evenly. Although the tolerance range 10...90 % will not be fully exploited.
The percentage figure in display zone 2 must decrease evenly. Although the tolerance range 90...10 % will not be fully exploited.
  Note!
t  The reason why the display in display zone 1 increases and the display in display zone 2 decreases is because the potentiometers (angle senders) in the throttle valve control part run in opposite directions.
t  This means that the voltage of one angle sender moves towards 5 volts. (The more the throttle valve is opened the higher the voltage; percentage figure increases).
t  Whilst the voltage of angle sender 2 decreases from 5 volts towards 0 volts. (The more the throttle valve is opened the lower the voltage; percentage figure decreases).
–  Press → key.
–  Press keys 0 and 6 for the function “End output” and confirm entry with the Q key.
–  Switch off ignition.
If the displays do not indicate as described:
–  Remove air cleaner → Fig..
  
Read measured value block 62           →

      

      

    
      

      

    
– 
          Pull 6-pin connector off throttle valve control part -arrow-.

      		 
      
    N24-1006
      

      

    
      

      

    
– 
          Measure resistance at throttle valve drive between contacts 3 + 5 Specification: 1.0...5.0 Ω
If the specification is not obtained:
– 
          Replace throttle valve control part  → Item.
– 
          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.
– 
          Adapt engine control unit to throttle valve control part  → Chapter.
If the specification is obtained:
– 
          Check voltage supply of throttle valve control part and wiring to control unit  → Anchor.
– 
          Check the accelerator pedal position sender.  → Chapter
If the voltage supply and wiring is OK:
– 
          Replace engine control unit  → Chapter.
Checking voltage supply and wiring to control unit
Test conditions
l 
           The battery voltage must be at least 11.5 V.
Test sequence

      		 
      
    N24-1008
      

      

    
      

      

    
– 
          Connect Multimeter to measure voltage at connector contacts 2 + 6.
– 
          Switch on ignition. Specification: min. 4.5 V
– 
          Switch off ignition.

      		 
      
    M24-0068
      

      

    
      

      

    
– 
          Connect Multimeter to measure voltage at connector contact 2 and earth.
– 
          Switch on ignition. Specification: min. 4.5 V
– 
          Switch off ignition.
If the specifications are not attained:
– 
          Remove wiper arms and cowl panel:  → Electrical system; Rep. Gr.92

      		 
      
    M24-0069
      

      

    
      

      

    
– 
          Connect test box -V.A.G 1598/22- to control unit wiring harness.

      		 
      
    N24-0709
      

      

    
      

      

    
– 
          Check wires between test box and 6-pin connector (connector to control unit) for open circuit using current flow diagram. Contact 1+socket 68 Contact 2+socket 55 Contact 3+socket 80 Contact 4+socket 75 Contact 5+socket 66 Contact 6+socket 61 Wire resistance: max. 1.5 Ω
– 
          Additionally check wires for short to one another, to vehicle earth and to battery positive. Specification: ∞Ω
If no fault is detected in the pipes:
– 
          Check engine control unit voltage supply  → Chapter.

      		 
      
    M24-0048
      

      

    


Checking intake manifold pressure sender >
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