A8 Quattro Sedan V8-4.2L (AUX) (2001)
Brake Signal: Testing and Inspection
Brake light switch -F and brake pedal switch -F47, checking
Because the injection system operates with an accelerator pedal sensor (potentiometer) which may be faulty, the engine is throttled back for reasons of
safety when the brakes are applied. To do this the control module requires signals from the brake light switch and also the brake pedal switch.
This means, that if the brakes are operated when the accelerator pedal is held at a constant position the engine speed is immediately reduced. Incorrectly
adjusted switches may lead to un-required regulating process
-
Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by
entering address word "01". When doing this the ignition must be switched on. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial
Checks/Connecting VAS5051 or VAG1551" under "Powertrain Management" See: Testing and Inspection
Indicated on display
Rapid data transfer
HELP
Select function XX
-
Press buttons -0- and -8- to select function "Read Measuring Value Block" and confirm entry with -Q- button.
Indicated on display
Read Measuring Value Block
Input display group number XXX
-
Depress brake pedal
-
Press buttons -0-, -6- and -6- to select "Display Group 66" and confirm entry with -Q- button.
Display Group 066
Indicated on display
Read Measuring Value Block 66
->
1
2
3
4
-
Observe display in display field 2.