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 connects 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 |
Troubleshooting
If the signals are implausible, the faults are stored in the DDE control unit. Cruise control is deactivated as a result.
A switch is fitted on the clutch pedal for the purpose of registering clutch operation on vehicles with manual transmission.
The clutch switch switches to earth. The plausibility of the signal is checked together with cruise control.
The following table shows how the signal behaves:
|
Clutch switch is |
Clutch operated |
open |
Clutch not operated |
Closed |
Troubleshooting
If the signal is implausible, the faults are stored in the DDE control unit. Cruise control is deactivated as a result.
The position of the accelerator pedal is reported to the DDE control unit via analog voltage signals. The signals are generated by two pedal-travel sensors in the accelerator pedal module.
The accelerator sensors take their 5 V power supply and earth connection from the DDE control unit. Depending on the operating angle, the pedal-travel sensors return various voltages to the DDE control unit. The DDE control unit converts the voltage signals into the accelerator pedal setting.
The signal of pedal-travel sensor 2 always has half the signal voltage of pedal-travel sensor 1.
The idle, full throttle and kickdown positions are detected by way of voltages of the pedal position sensors.
Troubleshooting
The pedal-travel sensors are monitored for short circuit and interrupt as well as for plausibility in relation to one another.