instrument cluster 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
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Additional signals, checking 
     
Engine speed (RPM) signal, checking 
 
     
Note:  
     The engine speed signal is taken from terminal 
37 on the Engine Control Module (ECM). The 
signal is used for various functions including the 
RPM display in the instrument cluster. 
    
 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
 . 
-  Check wiring from test box socket 37 to instrument cluster according to 
wiring diagram for an open circuit. 
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Page 3 of 37

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Coolant temperature signal, checking
 
     
Notes:  
     
The engine control module receives the coolant 
temperature signal from the instrument cluster. 
When the signal is received, the charge 
pressure is reduced to prevent the engine from 
overheating. 
    
 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
 . 
-  Check wiring from test box socket 19 to instrument cluster according to 
wiring diagram for an open circuit. 
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Page 4 of 37

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Vehicle Speed Signal (VSS), checking
 
     
Notes:  
     
The vehicle speed signal is generated by the 
Vehicle Speed Sensor (VSS) -G68 (on the 
transmission) and is processed in the 
instrument cluster. 
     The processed signal goes to terminal 54 on 
the engine control module and is used for Idle 
Air Control (IAC) and for the damping of load 
change jolts when changing gear. 
     
- Start engine.
     
-  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 . 
     
-  Select "Read measured value block" (function 
08) and Display Group 5. Read Measuring Value Block 5  
1 
2 
3 
4
    
Indicated on display:  
Warning! 
During a road test in an airbag equipped vehicle, VAG1551 must 
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Page 7 of 37

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Fuel tank level signal, checking
 
     
Note:  
     
The Engine Control Module (ECM) receives the 
fuel tank level signal from the instrument 
cluster. 
     The processed signal enters on terminal 30 the 
Engine Control Module (ECM) and is used to 
determine certain malfunctions (e.g.: misfire) 
     
-  Connect VAG1598/31 test box to wiring harness 
for engine control module. Do not connect to the 
engine control module itself   Page 24
-20
 . 
     
-  Check wiring from test box socket 30 to 
instrument cluster according to wiring diagram 
for an open circuit and short circuit to B+/Ground 
(GND). 
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Page 29 of 37

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Read measuring value block 125  
1 
2 
3 
4
    
When indicated on display:  
-  Check indications in display fields 1 through 4.
   CAN capable control modules connected to the Engine Control Module 
(ECM) are indicated: 
 
No indication (display field empty): 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 (e.g. in case of malfunction) 
Read measuring value block 125   
ABS 1 
Combi 1 
    
Example:  
Note:  
Display group 125 indicates all systems that communicate with the Engine 
Control Module (ECM) via the CAN-bus. (In this example, the ABS control 
module and the instrument cluster). If these systems are not installed, the 
display fields in display group 125 that are intended for them will be 
empty. Display field 1 will indicate "Transmission 1" and display field 4 will 
indicate "A/C 1" if these systems are communicated with the Engine 
Control Module (ECM) via the CAN-bus. 
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