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Testing operation of warning lamp
- Start engine.
Specification: if no faults relating to the electronic throttle are stored in the fault memory, the EPC warning lamp
should light up for about 3 seconds after the engine is started.
If the EPC warning lamp does not light up:
- Test wiring from engine control unit to EPC warning lamp in dash panel insert as follows:
=> Current flow diagrams, Electrical fault finding and fitting locations binder
- Interrogate fault memory of engine control unit => Page
7 - Checking accelerator position senders-G79 and -G185
7.1 - Checking accelerator position senders-G79 and -G185
Accelerator position senders -G79 and -G185 are located on the accelerator pedal. Both senders inform the
engine control unit of the driver's throttle requirement (pedal position), but each functions completely inde‐
pendently of the other (redundancy principle). Both senders are located in a single housing.
- Connect vehicle diagnostic, testing and information system VAS 5051 (or fault reader V.A.G 1551) and
select engine electronics control unit by entering address word "01" ( => Page
.)
When doing this the ignition must be switched on.
-> Indicated on display:
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
-> Indicated on display:
Read measured value block Q
Enter display group number XXX
- Press the keys 0, 6 and 2 to select Display Group 62 and confirm entry with Q key.
-> Indicated on display:
Read measured value block 62
1 2 3 4
- Check display values for electronic throttle potentiometer voltages.
Display zones
1
2
3
4
Display Group 62: Electronic throttle potentiometer voltages with ignition on
Display
xx %
xx %
xx %
xx %
Indicates
Throttle valve angle
(angle sender 1)
Throttle valve angle
(angle sender 2)
Accelerator position
sender 1
Accelerator position
sender 2
Range
min.: 0 %
max.: 100 %
min.: 0 %
max.: 100 %
min.: 0 %
max.: 100 %
min.: 0 %
max.: 100 %
Specification
3...93 %
97...3 %
12...92 %
4...49 %
Audi A8 1994 ➤
Motronic injection and ignition system (6-cylinder) - Edition 02.1999
6.6 - Notes on EPC warning lamp (fault warning lamp for electronic throttle) in dash panel
insert
81
