Throttle position signal
 
  
 
 
  
  
   
   
    
     Output signal to automatic transmission
    
    
     Fault symptoms
    
   
   
    CHECK ENGINE lamp (MIL) on. CHECK GEARBOX lamp on.
    
    
    
     Conditions
    
   
   
    Diagnostic trouble code: P1624 Motronic 4.1, control module
    
    
   
   
    Diagnostic trouble code: P1785 Transmission control module (TCM).
    
    
    
     Diagnostic procedure
    
    
     1. Check the wiring
    
    
      
    
    
   
   
  
    
  
  
  
  
   
    
     
      | - | Remove the Motronic control
module and the transmission control module. 
 
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      | - | Check for continuity in the lead
between: 
 
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      | - | Check the lead for open circuit and
shorting. 
 
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   Is the lead OK?
  
  
  
   
    Continue with point 2.
    
    
   
  
  
  
  
   
    Rectify the fault. Continue with point 3.
    
    
   
  
  
  
   2. Check the output signal
  
  
    
  
  
  
  
   
    
     
      | - | Plug in the Motronic control
module. 
 
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      | - | Turn the ignition switch to the ON
position. 
 
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      | - | Take a reading of the frequency on
the connector for the transmission control module, between 
 
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   The frequency should be 100 Hz.
   
   
   
    Are the temperature readings OK?
   
   
   
    
     Continue with point 3.
     
     
    
   
   
   
   
    
     Continue as described in
     
       .
     
     .
     
     
    
   
   
   
    3. Final check
   
   
     
   
   
  
  
  
   
    
     
      | - | Clear the diagnostic trouble
codes. 
 
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      | - | Implementation of driving cycle: 
 
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      | - | Evaluation of driving cycle: 
 
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   Has the diagnostic trouble code recurred?
  
  
  
   
    Continue fault diagnosis as described in Service Manual 4:2 "Automatic
transmission".
    
    
   
  
  
  
  
   
    The steps taken to rectify the fault were correct.