air condition AUDI A4 1999 B5 / 1.G APB Engine Electronic Engine Power Control Checking Workshop Manual
[x] Cancel search | Manufacturer: AUDI, Model Year: 1999, Model line: A4, Model: AUDI A4 1999 B5 / 1.GPages: 39, PDF Size: 0.16 MB
Page 1 of 39

24-139
 
     
Electronic Engine Power 
Control (EPC), checking 
     
Function of Engine Power Control (EPC)
 
      With the electronic throttle, the throttle valve is 
not operated by a cable connected to the 
accelerator pedal. There is no mechanical link 
between the accelerator pedal and the throttle 
valve.  
      The throttle valve is actuated by a servomotor 
(throttle valve positioner) in the throttle valve 
control module over the full range of engine 
speeds and load conditions.  
      The throttle valve positioner actuates the throttle 
valve according to the commands it receives 
from the Engine Control Module (ECM).  
      The position of the accelerator pedal is 
communicated to the Engine Control Module 
(ECM) by two accelerator position sensors 
(variable resistors, both installed in a single 
housing) which are connected to the accelerator 
pedal.  
      The accelerator pedal position (as determined by 
the driver) is one of the main input values for the 
Engine Control Module (ECM).  
Pa
ge 1 of 39 Electronic En
gine Power Control 
(EPC
), checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.4 
Page 3 of 39

24-141
       Under certain engine load conditions there is 
also a significant reduction in harmful emissions 
and noticeably improved fuel consumption.  
      The Engine Control Module (ECM) can provide 
the optimum combination of throttle valve 
opening and charge pressure in order to create 
the required torque.  
      The electronic throttle is not simply a 
combination of two or three components, but 
rather a complete system comprising all the 
elements that together determine the position of 
the throttle valve and also control and monitor it. 
For example, the Accelerator Pedal Position 
Sensor, Throttle Valve Control Module, EPC 
warning lamp, Engine Control Module (ECM) 
etc.  
Pa
ge 3 of 39 Electronic En
gine Power Control 
(EPC
), checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.4 
Page 13 of 39

24-148
      
Test conditions for adaptation of throttle 
valve control module  
     
No malfunctions stored in DTC memory   
Page 01
-15
 , check DTC memory 
     
Engine not running, ignition switched on 
     Accelerator pedal not depressed 
     Coolant temperature between 5 C and 
100 C (Display group 004, display field 3) 
     
Intake air temperature less than 100 C 
     
Voltage supply to engine control module 
greater than 11Volt, Checking   Page 28
-32
     
-  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. 
Pa
ge 13 of 39 Electronic En
gine Power Control 
(EPC
), checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.4 
Page 15 of 39

24-150
       When the -Q- button is pressed the throttle valve 
positioner will be switched mechanically.  
      In this condition the throttle valve is pulled into an 
"emergency running" or default position by a 
mechanical spring in the throttle valve control 
module. The values supplied by the two angle 
sensors for this emergency running position are 
stored in the Engine Control Module (ECM).  
      The throttle valve is then opened by a 
predetermined amount. As soon as it reaches 
this position the current supply to the throttle 
valve positioner is again disconnected. The 
spring should then close the throttle valve 
mechanically to the previously learned default 
position within a specified period of time (spring 
test).  
      The throttle valve positioner then closes the 
throttle valve and the values supplied by the 
angle sensors in the throttle valve control module 
are stored in the Engine Control Module (ECM).  
      If the ECM disconnects the current supply to the 
throttle valve positioner while the vehicle is being 
driven, the result will be an increase in idling 
speed with fluctuating engine RPM (hunting) and 
very slow throttle response.  
Pa
ge 15 of 39 Electronic En
gine Power Control 
(EPC
), checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.4 
Page 35 of 39

24-166
      
Kick-Down function, adaptation
 
      On vehicles with automatic/inifinitely variable 
transmission, when the accelerator position 
sensor or the Engine Control Module (ECM) was 
replaced, the Kick-Down function from ECM must 
be adapted.  
     
Test conditions  
     
No malfunctions stored in DTC memory   
Page 01
-15
 , check DTC memory 
     
Engine not running, ignition switched on 
     
-  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. 
Pa
ge 35 of 39 Electronic En
gine Power Control 
(EPC
), checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.4 
Page 37 of 39

24-168
 
  
Display fields  
  
1   2   3   4  
Display Group 063: Kick-down function adaptation  
Display   xx %   xx %  
  
---  
Indicated  accelerator 
position  
sensor 1  accelerator 
position  
sensor 2    
Adaptation condition  
Work  
range  0...100 %   0...100 %  
  
  
Kick Down  Activate  
ADP. runs  
ADP. OK  
ADP. ERROR  
Specified 
value  12...97 %   4...49 %  
Kick Down  
ADP. OK  
Note  
  
  
IF "ADP. ERROR" is displayed: Check DTC memory   Page 
01
-15
 .  
Note:  
 
The Abbreviation "ADP." stands for adaptation.
 The "ERROR" display could appear, if the accelerator pedal was not immediately depressed after you have been 
prompted or the accelerator pedal was released during the adaptation although the adaptation was not completely carried 
out. In both cases the "Basic Setting" mode must be abandoned and the adaptation must be started again   Page 24
-
Pa
ge 37 of 39 Electronic En
gine Power Control 
(EPC
), checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.4