Brief Description of Components
Brief Description Of Components
Dynamic stability control (DSC) comprises the following components:
- DSC unit
The DSC unit can be broken down into the components DSC control unit and hydraulic unit. The DSC control unit regulates the pressure in the brake system via the hydraulic unit (comprises valve block and pump motor). ~
- 4 wheel speed sensors
Each of the wheel speed sensors registers the speed of an individual wheel. In addition, the wheel speed sensors recognize the direction of rotation (forwards or backwards). ~
- DSC sensor
The DSC sensor measures the rotation of the vehicle around the vertical axis (yaw rate) and the lateral acceleration of the vehicle. A car fitted with Active Front Steering has two DSC sensors (redundancy). The DSC sensors connected to the DSC and AFS control units via the chassis
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- Steering-angle sensor
The steering-angle sensor registers the movements of the steering wheel. The steering-angle sensor is part of the steering column switch cluster (SZL).
On vehicles with active front steering, the cumulative steering angle is measured by the cumulative steering angle sensor (= steering angle at steering gear output). ~
- Internal brake pressure sensor
The DSC unit incorporates a brake-pressure sensor. This brake pressure sensor registers the
braking pressure applied by the brake pedal and the brake booster.
- 2 additional brake pressure sensors (only in combination with Active Cruise Control, ACC)
Two more brake pressure sensors are integrated, one in the front brake circuit and one in the rear brake circuit. A car fitted with Active Cruise Control (ACC) is slowed by the DSC when necessary. The braking pressure applied in this way at the front and rear wheels is often very low. It is controlled by means of the brake pressure sensors (objective: to equalize the brake load at the front and rear axles on long downhill stretches).
- 2 brake pad wear sensors
The brake pad wear sensors (front left and rear right) monitor the thickness of the brake pads. The Condition Based Service indicator (CBS) in the instrument cluster lights up if brake pad wear progresses to the point at which it becomes critical.
- Brake light switch
The brake light switch tells the DSC when the brake pedal has been pressed.
- Brake fluid level switch
If the brake fluid level is too low, this will be registered and the DSC control unit will be informed. An insufficient brake fluid level will be indicated on the instrument cluster by the general brake system warning light (signal via CAN bus).
- DSC button
The DSC button located on the centre console switch cluster (SZM) has 3 switch positions:
DSC in standby, DTC in standby, DSC completely switched off. The DSC control unit also communicates with the following control units:
- DME
The OME I DDE controls engine adaptation (for example, reduction in engine output to prevent spin at the driven wheels). The DME I DDE also receives the converted wheel speed signal from the rear right wheel. This signal is used to check the plausibility of engine misfires (DME).
- Car Access System (CAS) or Multi-Audio System Controller (M-ASK)
CAS and M-ASK receive the converted wheel speed signal from the rear left wheel. Both these control units use this signal to ascertain whether the car is moving or at a standstill.
- Safety and gateway module (SGM)
The SGM is the gateway between:
^ PT-CAN
^ K-CAN
^ byteflight
^ Diagnosis bus
- Active Cruise Control (ACC)
The DSC receives requests from the Active Cruise Control (ACC) via the PT-CAN. In response, the DSC reduces speed by applying the brakes at all four wheels.
- Light Module (LM)
As required by law, the brake lights are activated in the event of automatic braking when the Electronically Controlled Deceleration function (ECD) is triggered by the ACC. This function requires a signal to be sent via the K-CAN to the light module.
- Instrument cluster
The DSC control unit actuates the indicator and warning lights for DSC in the instrument cluster.
- Electronic gearbox control (EGS) (vehicles with automatic transmission)
The PT-CAN carries the wheel speed signals to the gearbox controller. The gearbox controller responds by adapting the gearshift characteristics for cornering and ascents. The gearshift characteristics are also adapted by the system if it detects wintry driving conditions (high degree of wheel slip).
In addition, gearshifts are disabled while the DSC is actively intervening.
- Central Information Display (CID) and controller
The CID shows the detailed explanatory texts of the Check Control messages. CID and controller are also used to initialize the runflat indicator.
- Telephone control unit with GPS antenna
If the car is not fitted with a navigation system, the telephone control unit receives the converted wheel speed signals from the front left and right wheels.
The telephone control unit uses these signals to pinpoint the cars position as precisely as possible.