P0138
Read the instructions below then 
start the fault diagnostic procedure.
Symptom: CHECK ENGINE.
 
  
 
 
  
  
   
   
    
    
     
     
     O2S Circuit. High Voltage. Sensor 2.
    
    
     
    
    
   
   
  
   Fault symptoms
  
  
  
   
  
  
  
   On-Board Diagnostics
  
  
   
    Type of diagnosis:
   
   
   
  
  
  
   
    
     
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       Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.
        
        
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    Enable criteria:
   
   
   
  
  
  
   
    
     
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       General conditions for this trouble code: Atmospheric pressure must exceed 72 kPa and the engine coolant and intake air temperatures must exceed -7°C.
        
        
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       Engine running. Main relay voltage exceeding 10V.
        
        
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    Fault criteria:
   
   
   
  
  
  
   
    
     
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       Voltage higher than 1.250 V for more than 2 s.
        
        
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    Dependents:
   
   
   
  
  
  
   
  
  
  
   
    System reaction to a fault:
   
   
   
  
  
  
   
    
     
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       Transition adaptation of closed loop is blocked.
        
        
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    OK report:
   
   
   
  
  
  
   
    
     
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       P0140 diagnosis performed once and fault criteria not fulfilled. Fault criteria for P0138 not fulfilled.
        
        
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    Fault handling:
   
   (See section
   
    Fault handling III, other emission-related components and functions
   
   for more information.)
   
   
  
  
  
   
  
  
  
   Diagnostic help
  
  
   Fault diagnosis concerns an electrical fault in connecting leads or in the sensor.
   
   
  
  
   Functions in the diagnostic tool related to the fault:
   
   
  
  
  
   
    
     
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       Diagnostic status for the diagnosis.
        
        
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       Oxygen Sensor Value, unit V.
        
        
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   See also description of read values in
   
    Menu "Read Values"
   
   for more information.
   
   
  
  
   
    
     
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       Note
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        Oxygen sensor receives reference oxygen from the surrounding air via the connecting cables. For this reason, electrical contact spray or grease
        
         must not
        
        be used on the oxygen sensor connector.
        
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    Checking the wiring
   
  
  
   Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.