EHC control unit
The EHC control unit (EHC = Electronic Height Control) decides whether there is a need for adjustment to compensate for changes in the load. The vehicle heights and vehicle conditions are taken into account here. The EHC control unit prevents adjustments caused any other way. This makes it possible to gear the intervention to each situation as regards optimum frequency, target height, tolerance thresholds and battery load. In addition to handling the self-levelling suspension, the EHC control unit has the task of monitoring the system components and saving faults.
| Item | Explanation |
|---|---|
| 1 | EHC control unit |
| 2 | 26-pin plug connection |
The EHC control unit recognizes the different operating conditions from the incoming signals and messages. Depending on the drive status, the EHC control unit switches into the corresponding control functions.
The EHC control unit processes the following signals and bus signals:
- Vehicle ride height from ride height sensors located at the rear right and rear left.
- Terminal 15 ON or OFF or terminal R (bus signal terminal status from CAS or BDC)
- Driving speed (bus signal driving dynamics from Integrated Chassis Management ICM)
- Lateral acceleration (bus signal driving dynamics from Integrated Chassis Management ICM)
- 'Engine running' signal (bus signal from DME or DDE)
- Information about the status of the doors and the tailgate (bus signal flap status from CAS, FRM, JBE, BDC)
- Kilometer reading (bus signal from the instrument panel)
- Trailer detection (bus signal from the AHM control unit)
- Status of the Tire Pressure Monitor or Run Flat Indicator (bus signal from the RDC control unit or DSC control unit).