ignition AUDI A4 1995 B5 / 1.G APB Engine Additional Signals Checking Workshop Manual
[x] Cancel search | Manufacturer: AUDI, Model Year: 1995, Model line: A4, Model: AUDI A4 1995 B5 / 1.GPages: 37, PDF Size: 0.14 MB
Page 6 of 37

24-183
      
-  Take vehicle for a test drive and check whether 
vehicle speed appears in display field 3. 
     
-  If vehicle speed does not appear, raise the 
vehicle (preferably using a lift) until front left 
wheel is clear of the ground. 
    
 Electrical Wiring Diagrams, Troubleshooting & Component Locations    -  Connect VAG1598/31 test box to wiring harness for engine control 
module. Do not connect to the engine control module itself   Page 24
-
20
 . 
-  Connect diode test lamp between socket 3 (B+) and socket 54 (vehicle 
speed signal). 
-  Switch ignition on and turn front left wheel by hand.
   The diode test lamp should flash (very brief flashes).
-  If diode test lamp does not flash, check for open circuit or short to B+ 
or Ground (GND) in wiring between instrument panel and terminal 54 
on engine control module connector. 
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Page 8 of 37

24-185
      
Brake light switch -F and brake pedal 
switch -F47, checking 
 
     
-  Connect vehicle diagnostic, testing and 
information system VAS 5051 or VAG1551 scan 
tool and select engine electronics control 
module by entering address word "01"   Page 
01
-9 . 
      When doing this the ignition must be switched 
on.  Rapid data transfer 
HELP
Select function XX
    
Indicated on display  
-  Press buttons -0- and -8- to select function "Read Measuring Value 
Block" and confirm entry with -Q- button. 
Read Measurin
g Value Block 
Input displa
y group number XXX
    
Indicated on display  
-  Press buttons -0-, -6- and -6- to select "display group number 066" and 
confirm entry with -Q- button. 
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Page 12 of 37

24-189
       If specifications are not met:  
     
Check voltage supply  
     
-  Connect VAG1527 B between following sockets 
on harness connector: 
     
Harness connector 
terminal  
Measure 
against  
1   Ground (GND)  
     
 
The LED must come on
     Harness connector 
terminal  
Measure 
against  
3   Ground (GND)  
     
-  Switch ignition on.
     
 
The LED must come on
      If LED does not come on:  
     
-  Check wiring connection from terminal 1 or 3 of 
connector for open circuit (fuse) or short circuit 
to Ground (GND). 
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Page 15 of 37

24-191
      
Clutch Vacuum Vent Valve Switch -F36, 
checking
 
     
Note:  
     This signal is used to avoid RPM over-oscillation 
and load change impacts when changing gears 
and is also used for the cruise control system. 
     
Test sequence 
     
-  Connect vehicle diagnostic, testing and 
information system VAS 5051 or VAG1551 scan 
tool and select engine electronics control 
module by entering address word "01"   Page 
01
-9 . 
      When doing this the ignition must be switched 
on.  Rapid data transfer 
HELP
Select function XX
    
Indicated on display  
-  Press buttons -0- and -8- to select function "Read Measuring Value 
Block" and confirm entry with -Q- button. 
Read Measurin
g Value Block 
Input displa
y group number XXX
    
Indicated on display  
-  Press buttons -0-, -6- and -6- to select "display group number 066" and 
confirm entry with -Q- button. 
Read Measuring Value Block 66 
    
Indicated on display  
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Page 20 of 37

24-194
       If specification is obtained:  
     
Check voltage supply  
     
-  Connect VAG1527 B between following sockets 
on harness connector: 
     
Harness connector 
terminal  
Measure 
against  
2   Ground (GND)  
     
-  Switch ignition on.
     
 
The LED must come on
      If LED does not come on:  
     
-  Check wire connection from terminal 2 of 
connector for open circuit (fuse) or short circuit 
to Ground (GND). 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations   
     
-  If necessary eliminate open circuit or short 
circuit to Ground (GND) 
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Page 28 of 37

24-202
      
Checking bus system  
      The principle of the test is independent of the 
number of control modules/systems connected to 
the CAN-bus.  
      The DTC table suggested checking the data 
exchange between the Engine Control Module 
(ECM) and CAN capable control modules.  
     
-  Start engine (if engine will not start, switch 
ignition on). 
     
-  Connect VAS5051 tester or VAG1551 scan tool 
and select the control module for engine 
electronics using "address word" 01   Page 01
-
9 . 
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
Enter displa
y group number XXX
    
When indicated on display:  
-  Press buttons -1-, -2- and -5- to select "display group number 125" and 
press -Q- button to confirm input. 
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Page 33 of 37

24-207
 
    
Example 1 
From the malfunctions present in the DTC memories, you can see that 
control module 1 has no connection to control modules 2 or 3.  
 Electrical Wiring Diagrams, Troubleshooting & Component Locations   Control module  
Stored malfunctions in DTC memory:  
1  
No message from control module 2No message from control module 3
2  No message from control module 1
3  No message from control module 1
-  Switch ignition off.
-  Disconnect control modules that are linked by bus wires and check 
whether there is an open circuit in one of the bus wires -  If no malfunction can be identified in the bus wires replace control 
module 1. 
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Page 34 of 37

24-208
 
    
Example 2 
From the malfunctions present in the DTC memories, you can see that 
control module 2 has no connection to control modules 1 or 3.  
 Electrical Wiring Diagrams, Troubleshooting & Component Locations   Control module  
Stored malfunctions in DTC memory:  
1  
No message from control module 2
2  No message from control module 1No message from control module 3
3  No message from control module 2
-  Switch ignition off.
-  Disconnect control modules that are linked by bus wires and check 
whether there is an open circuit in one of the bus wires -  If no malfunction can be identified in the bus wires replace control 
module 2. 
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Page 35 of 37

24-209
      
Example 3 
      From the malfunctions present in the DTC 
memories, you can see that none of the control 
modules are able to transmit or receive signals.  
     
Control 
module  
Stored malfunctions in DTC 
memory:  
1  Data Bus Powertrain 
Malfunction 
2  Data Bus Powertrain 
Malfunction 
3  Data Bus Powertrain 
Malfunction 
     
-  Switch ignition off.
    
 Electrical Wiring Diagrams, Troubleshooting & Component Locations    -  Disconnect the control modules which are linked by the bus wires and 
check for a short circuit between the bus wires 
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Page 36 of 37

24-210
 
    
If the cause of the malfunction "Data Bus Powertrain Malfunction" 
cannot be found in the data bus wires, check whether one of the 
control modules is causing the malfunction. 
At this stage all the control modules which communicate via the CAN data 
bus are disconnected. The ignition is switched off.  -  Check bus wires for short to B+ and short to Ground (GND).
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