BMW 7 Series: Electronic Ride-Height Control (EHC)

Control Unit

The EHC control unit is located in a module carrier in the rear of the luggage compartment on the right-hand side.

Fig. 132: Identifying Air Supply (LVA) And EHC Control Module On Mounting Bracket

INDEX REFERENCE CHART

1. Air supply (LVA)
2. EHC control module on mounting bracket

The EHC control unit is fully compatible with diagnostics.

The EHC control unit receives the following signals:

• Vehicle ride height
• Load cutout signals
• Terminal 15 ON/OFF
• Vehicle speed
• Lateral acceleration
• "Engine running" signal
• Hatch status.

The EHC control unit decides on a case-by case basis whether a control operation is required in order to compensate for changes in load.

It is thus possible to optimally adapt the frequency, specified heights, tolerance thresholds and battery load to the relevant situation by means of the control operation.

Air Supply Unit (LVA)

Fig. 133: Identifying Air Supply Unit Components, Top View

INDEX REFERENCE CHART

1. Compressor relay
2. Electric motor
3. Air exhaust silencer
4. Air drier
5. Electrical connector, 3-pin, for valve manifold
6. Electrical connector, 2-pin, for electric motor
7. Component carrier

The air supply unit is mounted at the rear of the vehicle on the trunk floor.

Fig. 134: Identifying Air Supply Unit Components, Bottom Vie

INDEX REFERENCE CHART

1. Electrical connector, 2-pin, for exhaust valve
2. Air intake line to left rear light unit
3. Air intake
4. Valve block
5. Compressor
6. Air drier
7. Air exhaust valve
8. Air exhaust silencer

Air Suspension

Fig. 135: Identifying Air Suspension Components

AIR SUSPENSION SYSTEM COMPONENT REFERENCE CHART

1. Left air spring strut
2. Right air spring strut
3. EHC control unit
4. Air supply unit
5. Compressor relay

Ride-height Sensor

Fig. 136: Identifying Ride-Height Sensor Components

RIDE-HEIGHT SENSOR COMPONENT REFERENCE CHART

1. Electrical connector
2. Sensor housing
3. Lever

The angle of a pivoting lever is converted into a voltage signal by the ride height sensor. The greater the angle (relative to a defined starting or zero position), the greater is the output voltage. It is generated by a Hall-effect sensor element.

Designs

There are always four ride-height sensors fitted on all F01/F02 models.

The ride-height sensors fitted all operate according to the same principle but there are different designs (different part numbers). The reason for the differences are the available space and the starting position (zero position) of the individual ride-height sensors.

Depending on whether or not the vehicle is fitted with Electronic Height Control (EHC), double or single ride-height sensors are fitted on the rear suspension.

On the front suspension, single ride-height sensors are always used.

FRONT AND REAR SUSPENSION DESIGN

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