Two switches are fitted on the brake pedal which supply the following signals:
The DDE control unit evaluates the signals for the purpose of registering brake operation.
The brake-light switch connects to earth, the brake-light test switch to positive. Both signals are checked for plausibility.
The following table shows how the signals behave:
|
Brake light switch is |
Brake light test switch is |
Brake pedal operated |
Open |
Closed |
Brake pedal not operated |
Closed |
Open |
If the signals are implausible, the faults 4083, 3F48 are stored. Cruise control is deactivated as a result.