Page 12 of 37

21-11
 
    
Notes:  -  Switch on turbocharger tester and set measuring range selector switch 
to position -I- (absolute pressure). 
-  Connect measuring hose to connection -I-. 
Hose connections must be completely airtight, otherwise 
measurements will not be correct. Ensure that measuring hose is not pinched at hood or side window.Pressing memory key M on turbocharger tester will store the last 
measured value until memory key M is pressed again or tester is 
switched off. The decimal point in the display flashes to indicate that the value is 
being stored. If the battery voltage of the turbocharger tester drops below the 
minimum level, an arrow will appear at the top left of the display. Before performing the test, drive the vehicle at a brisk speed for at 
least 3 km (without stopping at traffic lights etc.). A second mechanic is required to note the readings on the tester 
when the vehicle is moving. Observe safety notes   Page 21
-9 .
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        Page 15 of 37
21-14
      
Test sequence  
    
 Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition, 
Engine Code(s): APB, Repair Group 01
    -  Connect VAS 5051 tester or VAG 1551 scan tool and select control 
module for engine electronics using "address word" 01. Engine must 
run at idle. 
Rapid data transfer  
HELP
Select function XX
    
When indicated on display  
-  Press buttons -0- and -8- to select "Read Measuring Value Block" and 
press -Q- button to confirm input. 
Read measurin
g value block 
Q
Input displa
y group number XXX
    
When indicated on display  
-  Press buttons -1-, -1- and -5- to select "display group number 115" and 
press -Q- button to confirm input. 
Read Measuring Value Block 115 
    
Indicated on display (1...4   display fields)  
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        Page 17 of 37
21-15
      
-  Road test vehicle.
     
 
Wide Open Throttle (WOT) must be 
reached 
     
-  Measurement must be taken at Wide Open 
Throttle (WOT). 
  
Display fields  
  
1   2   3   4  
Display group 115: Charge air pressure regulation  
Display   1 RPM   %   mbar   mbar  
Indicated   Engine speed (RPM)   Actual load   Specified pressure   Actual pressure  
Specified value         XXX   Must not deviate more  
than +/- 20 mbar  
from specified  
Note:                    Actual pressure must not deviate from specified 
pressure by more than   20 mbar.  
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        Page 18 of 37
21-16
      
-  Select measuring value block 117.
     
-  Check function of accelerator pedal in display 
field 2 by briefly depressing pedal to Wide Open 
Throttle. 
  
Display fields  
  
1   2   3   4  
Display group 117: Charge air pressure regulation  
Display   1 RPM  
%   %   mbar  
Indicated   Engine speed (RPM)  
Accelerator pedal 
position  Throttle valve angle   Specified charge air 
pressure  
Specified value    
0...100        
Note:                    If the specified value 100% is not reached at 
Wide Open Throttle (WOT):  
     
- Check accelerator pedal.
     
-  Select measuring value block 116.
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        Page 19 of 37
21-17
      
-  Check correction factors in display fields 2 to 
4. 
  
Display fields  
  
1   2   3   4  
Display group 116: Charge air pressure regulation  
Display  1 RPM  
%  %  mbar  
Indicated   Engine speed (RPM)  
Correction factor  
Fuel  Correction factor  
Coolant temp.  Correction factor  
Intake air temp.  
Specified value      
  
  
Note:                    If display field 2 indicates a correction factor <0 
%, fuel quality is probably incorrect.  
     
-  Fill tank with prescribed fuel quality.
      If display field 3 indicates a correction factor <0 
%, coolant temperature is too high (heat warning 
lamp lit in instrument cluster) or the Engine 
Control Module is receiving an incorrect 
temperature signal from the instrument cluster.  
     
-  Check coolant temperature display.
     
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        Page 21 of 37
21-18
       If display field 4 indicates a correction factor <0 
%, intake air is too hot or the sensor for intake air 
temperature is faulty.  
     
       Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel 
Injection & Ignition, Engine Code(s): APB, Repair Group 24
   
     
-  Select measuring value block 114.
  
Display fields  
  
1   2   3   4  
Display group 114: Charge air pressure regulation  
Display  
%  
%  
%  %  
Indicated  
Specified engine load (without 
correction)  Specified engine load (after 
correction)  Actual 
load  Duty cycle  
CAPR-cyclical 
valve  
Specified 
value  136,0  
134,3  
137,5  55,2  
Note:                    Load values in display fields 1 to 3 can deviate 
from each other by up to   5 %.        If specified values are not achieved in the 
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        Page 24 of 37
21-20
      
Note:  
     The recirculating valve for turbocharger -N249 
and wire connections are monitored by the 
Engine Control Module (ECM). 
     
-  Connect VAS 5051 tester or VAG 1551 scan 
tool and select control module for engine 
electronics using "address word" 01. Engine 
must run at idle for this. 
     
       Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel 
Injection & Ignition, Engine Code(s): APB, Repair Group 01
   
     
-  Check DTC memory of Engine Control Module 
(ECM). 
     
       Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel 
Injection & Ignition, Engine Code(s): APB, Repair Group 01
   
      If a Diagnostic Trouble Code (DTC) relating to 
the recirculating valve for turbocharger -N249- is 
displayed:  
     
- 
Disconnect hoses from valve; harness connector 
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        Page 26 of 37
21-21
      
-  Initiate output Diagnostic Test Mode (DTM) and 
activate recirculating valve for turbocharger -
N249-. 
     
       Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel 
Injection & Ignition, Engine Code(s): APB, Repair Group 01
   
Output diagnostic test mode Recr. valve for turbocharger -N249
    
Indicated on display  
If valve does not click:  
If valve does not open and close properly:     Valve must click...
   ...and must open and close (can be tested by blowing into assisting 
hose). 
-  Check internal resistance of valve.
-  Replace recirculating valve for turbocharger -N249-.
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