Page 5 of 44

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Test sequence  
     
-  Connect VAS5051 tester or VAG1551 scan tool 
and select the control module for engine 
electronics using "address word" 01   Page 01
-
9 . 
     
   Engine must run at idle for this.
     
WARNING! 
     
Observe safety precautions to reduce the risk 
of accidents during road test   Page 24
-1 . 
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 -0-, -0- and -5- to select "display group number 005" and 
press -Q- button to confirm input. 
Read Measuring Value Block 5  
1 
2 
3 
4
    
Indicated on display:  
-  Determining via road test whether vehicle speed is displayed in display 
field 3. 
-  If vehicle speed is not display, lift vehicle -if possible using a vehicle lift-
until front left wheel is free. 
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        Page 10 of 44

24-173
      
Test sequence  
     
-  Connect VAS5051 tester or VAG1551 scan tool 
and select the control module for engine 
electronics using "address word" 01   Page 01
-
9 . 
     
   Engine must run at idle for this.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 display group number XXX
    
When indicated on display:  
-  Press buttons -0-, -5- and -0- to select "display group number 050" and 
press -Q- button to confirm input. 
Read Measuring Value Block 50  
1 
2 
3 
4
    
Indicated on display: (1 thru 4   display fields)  -  Switch A/C system off. 
 
Specified value in display field 4: Compr. OFF
-  Switch A/C system on using "Auto" button and adjust A/C system to 
maximum cooling or heating power. Compressor must run. 
 Specified value in display field 4: Compr. ON
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        Page 13 of 44
24-175
      
A/C system signal, checking
 
      The A/C system signal notifies the Engine 
Control Module (ECM), that the A/C system 
requires a higher idle speed to achieve the 
desired interior temperature (regardless of 
whether heating or cooling is required).  
      The increase in idle speed based on presence of 
the A/C system signal is control module 
dependent and occurs only in vehicles with All 
Wheel Drive (AWD) and manual transmission.  
     
Test sequence  
     
-  Connect VAS5051 tester or VAG1551 scan tool 
and select the control module for engine 
electronics using "address word" 01   Page 01
-
9 . 
     
   Engine must run at idle for this.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. 
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        Page 14 of 44

24-176
 If specified values are not obtained:  
Read Measuring Value Block 
Q
Input displa
y group number XXX
    
When indicated on display:  
-  Press buttons -0-, -5- and -6- to select "display group number 056" and press -Q-
button to confirm input. 
-  Switch on A/C system, press "Auto" button and select the lowest temperature.
-  Check indications in display field 3 and 4.
  
Display fields  
  
1   2   3   4  
Display group 056: Idle stabilization with engine at idle and operating temperature  
Display   xxx /min   xxx /min  
---  
---  
Indicated   Engine speed (actual)   Engine speed (specified)  
A/C readiness  
A/C compressor  
Functional range    
    
A/C - LOW  
A/C - HIGH  Compr. OFF  
Compr. ON  
Specified value  
720 to 820 RPM 
1)  
630 to 730 RPM 2)  760 RPM 
1)  
680 RPM 2)  A/C - HIGH  
Compr. ON  
1) Front Wheel Drive Vehicles  2) All-Wheel Drive Vehicles  
-  Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM   Page 24
-17
 .
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        Page 16 of 44

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Brake light switch and brake pedal 
switch, checking
 
     
Note:  
     For safety reasons, the instruction from the 
accelerator pedal sensor (potentiometer) to the 
ECM to open the throttle valve is suppressed 
when brake is being operated. This requires the 
brake light switch signal and also the brake pedal 
switch signal in the control module. 
     If brake pedal is operated with accelerator pedal 
constantly depressed, engine is immediately 
regulated down to idle speed. A faulty switch can 
lead to undesired regulation. 
     
Test sequence  
     
-  Connect VAS5051 tester or VAG1551 scan tool 
and select the control module for engine 
electronics using "address word" 01   Page 01
-
9 . 
     
   Ignition must remain switched on for this.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. 
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        Page 17 of 44
24-179
 
Read Measurin
g Value Block 
Q
Input display group number XXX
    
When indicated on display:  
-  Press buttons -0-, -6- and -6- to select "display group number 066" and 
press -Q- button to confirm input. 
Read Measuring Value Block 66  
1 
2 
3 
4
    
Indicated on display:  
-  Check brake light/brake pedal switch in display field 2.
  
Display fields  
  
1   2   3   4  
Display group 066: Signals to Engine Control Module (ECM)  
Display  xxx km/h  
XXXX  xxx km/h  XXXX  
Indicated  ACTUAL speed  
Switch positions   SPECIFIED speed   Switch positions  
Functional range    
  XX00  
XX11       
Specified value    
XX00  
(with brake pedal 
not operated)       
    
XX11  
(with brake pedal 
operated)       
Notes    
Value: 
X = no significance.       
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        Page 24 of 44
24-183
      
Clutch vacuum vent valve switch -F36-, 
checking
 
     
Note:  
     This signal helps prevent excessive RPM 
oscillations and tip-in shocks when clutch is 
disengaged and is required for the cruise control 
system. 
     
Test sequence  
     
-  Connect VAS5051 tester or VAG1551 scan tool 
and select the control module for engine 
electronics using "address word" 01   Page 01
-
9 . 
     
   Ignition must remain switched on for this.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 -0-, -6- and -6- to select "display group number 066" and 
press -Q- button to confirm input. 
Read Measuring Value Block 66 
    
Indicated on display:  
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        Page 38 of 44
24-193
 
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 Measuring Value Block 
Q
Input displa
y group number XXX
    
When indicated on display:  
Note:  
Measuring value blocks 125 and 126 indicate the components that are 
part of the powertrain data bus.  -  Press buttons -1-, -2- and -5- to select "display group number 125" and 
press -Q- button to confirm input. 
-  Check indications in display fields 1 through 4.
   CAN capable control modules connected to the Engine Control Module 
(ECM) are indicated: 
 
No indication: Control module not CAN capable
 Indication 1: CAN capable control module is connected to databus
 Indication 0: CAN capable control module is not connected to 
databus 
- 
Press button.
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