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Test the voltage supply and the wiring to the control unit > < Post-catalyst lambda probe heating: testing

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Throttle valve drive unit: testing
   
Throttle valve drive unit: testing
Components Throttle valve drive unit -J338-: Throttle valve drive -G186-, Throttle valve drive angle sender 1 -G187- and Tthrottle valve drive angle sender 2 -G188-.
  Note!
After replacing the throttle valve drive unit, the new drive unit must be adapted to the engine control unit → Chapter.
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 conditions
l  Throttle valve not damaged or dirty.
l  Coolant temperature, 80 °C minimum → Anchor, display field 3.
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, 6 and 2 for “Display group number 62” and press Q to confirm the entry.
  
Read measurement value block        HELP
Enter display group number XXX
The display reads: (1...4 = display fields)
–  Test the throttle valve angle at the idling limit, received by sender 1 -G187- and displayed in display field 1 Target value: 10...90 %
–  Test the throttle valve angle at the idling limit, received by sender 2 -G188- and displayed in display field 2 Target value: 90...10 %
–  Slowly depress the accelerator pedal to full gas, watching the angles displayed in displays fields 1 and 2: The percentage displayed in display field 1 should rise steadily. Not the whole tolerance range of 10...90 % is used. The percentage displayed in display field 2 should fall steadily. Not the whole tolerance range of 90...10 % is used.
  Note!
t  The value rises in display field 1 and falls in display field 2 because the potentiometers (angle senders) in the throttle valve drive unit function in the opposite way.
t  This means that the voltage received by one of the angle senders approaches 5 volts (the more the throttle valve opens, the more voltage rises; the value in percentage rises).
t  The voltage received angle sender 2 moves away from 5 volts and approaches 0 volts (the more the throttle valve opens, the more voltage falls; the value in percentage falls).
–  Press →.
–  Press 0 and 6 for the function “End data transmission” and press Q to confirm the entry.
–  Switch off the ignition.
If the described messages do not appear:
–  Remove the air filter → Fig.
  
Read measurement value block    62    ->
         1         2         3         4
–  Unplug the 6-pin connector from the throttle valve drive unit -arrow-.
  E24-0030
–  Measure the resistance of throttle valve operation between contacts 3 + 5 Target value: 1.0...5.0 Ω.
If the target value is not reached:
–  Replace the throttle valve drive unit → Item.
–  Consult the fault memory; eliminate any faults and clear the memory → Chapter, Fault memory: consulting and clearing.
–  Adapt the engine control unit to the throttle valve drive unit → Chapter.
If the target value is reached:
–  Test the throttle valve drive unit voltage supply and the wiring to the control unit → Chapter.
–  Test the accelerator pedal position senders: → Rep. Gr.20.
If no fault is found in the voltage supply and wiring:
–  Replace the engine control unit → Chapter.
  E24-0031

Test the voltage supply and the wiring to the control unit > < Post-catalyst lambda probe heating: testing