BMW 7 Series: Periphery Of ICM Control Unit

Bus Systems

Fig. 45: Routing Diagram - ICM Control Unit With Flexray, Local CAN And Wake-Up Line

INDEX REFERENCE CHART

1. Central gateway module
2. Dynamic Stability Control
3. Short range radar sensor (SRR), left
4. Long range radar sensor (LRR)
5. Short range radar sensor (SRR), right
6. DME/DDE control unit
7. ICM control unit
8. FlexRay routing and continuation without terminating resistor
9. Routing of FlexRay with terminating resistor
10. Routing of local CAN without terminating resistor
11. Routing of local CAN with terminating resistor

W - ICM control unit can be woken up
WUP - Wake-up line

FlexRay

The ICM control unit is connected to the FlexRay controller via the FlexRay bus system. The communication with virtually all partner control units is handled by the microprocessors in the ICM.

The FlexRay is routed to the ICM control unit (from the central gateway module) and continues from there (to the DME/DDE). The ICM control unit is related to the FlexRay, i. e. not an end node. This is why it does not have a terminating resistor for the FlexRay.

Local CAN

A further bus system, a local CAN, is connected to the ICM control unit in addition to the FlexRay. This serves the ICM exclusively for the purposes of communication with the active speed control radar sensors. This local CAN therefore performs the same tasks as the sensor CAN in the E6x LCI that connects the LDM control unit to the radar sensors. It transmits information on road users that has been recorded by the radar sensors.

The local CAN operates in the same way as the PT-CAN with a data transfer rate of 500 kBit/s. There are two terminating resistors for the local CAN, each with 120. One of these is in the ICM control unit, the second is integrated in the long range radar sensor (LRR). The close range sensors (SRR) are routed to the local CAN via short lines.

The pins for the local CAN are only connected at the plug of the ICM control unit if it is a high-performance version.

Wake-up line

The ICM control unit is also connected to the wake-up line. The ICM control unit can be woken up via the wake-up line.

Power Supply

The only external power supply to the ICM control unit is with terminal 30B. This is made available by the junction box electrical system and the fuse carrier at the front.

The electronics and integrated sensor system are therefore supplied inside the ICM control unit. Additionally, the ride-height sensors connected to the ICM control unit and the output stages for activation of the valves for the steering unit are also supplied.

Ride-height Sensors

Fig. 46: Identifying Ride-Height Sensors Components

RIDE-HEIGHT SENSOR COMPONENT REFERENCE CHART

1. Connector
2. Housing
3. Arm (pivoting)

Design and principle of operation

The angle of a pivoting arm is converted to a voltage signal via the ride-height sensors. The greater the angle (with reference to a defined starting position), the greater the output voltage generated by a Hall sensor element.

Versions

Four ride-height sensors are installed in every F01/F02 as standard equipment.

However, the ride-height sensors installed in the vehicle are available in different versions. Different ride-height sensors are used on the left and right of the front axle.

Different ride-height sensors are also used on the rear axle. The reasons for this in both cases are the available installation space and the starting position.

Double or single-type ride-height sensors are used at the rear axle, depending on whether the vehicle is equipped with electronic ride-height control (EHC). Single-type ride-height sensors are always used at the front axle.

RIDE-HEIGHT SENSOR VERSIONS

Interface with ICM control unit

As shown in the system circuit diagram, each ride-height sensor (irrespective of the version) is connected to the ICM control unit by three lines. The double-type ride-height sensors at the rear axle are also connected to the EHC control unit according to the same principle via three additional lines.

Power is supplied by the ICM control unit to the ride-height sensor via one of the lines. The sensor uses the second line to deliver its measurement signal (0-5 V DC voltage). The third line is connected to a common ground inside the ICM control unit.

The measurement signal is evaluated by means of voltage measurement in the ICM control unit. The ICM control unit cannot calculate the actual ride-level heights in millimeters on the basis of this information alone.

To perform this calculation, the ICM control unit must be able to map the voltage signals it receives to reference values. This is the only way to establish a relationship between the measurement signals and the actual ridelevel heights. These reference values are determined during a synchronization procedure.

NOTE: The ride-height signals in the ICM must be synchronized in the following cases

• following replacement of the ICM control unit,
• following replacement of a ride-height sensor or
• if prompted to do so by the test schedule of the diagnostic system (due to a fault code memory entry in the ICM).

The synchronization does not have to be carried out if a wheel has been changed.

Driving Dynamics Switch

The driving dynamics switch and DTC button are integral components of the center console operator control unit.

Fig. 47: Identifying Driving Dynamics Switch And DTC Button Installation Location

INDEX REFERENCE CHART

1. DTC button
2. Driving dynamics switch, "SPORT" rocker switch
3. Driving dynamics switch, "COMFORT" rocker switch

The new driving dynamics switch consists of two buttons labeled "COMFORT" and "SPORT". This is a rocker switch that returns automatically to the center position after it is pressed. The center position corresponds to the "no button pressed" status.

Both buttons of the driving dynamics driving switch are connected directly to the ICM control unit via two lines. The ICM control unit applies a voltage at these lines. Both buttons are connected to the ground via a resistance network. The ICM control unit can determine the following by back-scanning the voltage obtained:

• whether a button has been pressed and, if so, which of the two buttons,
• whether breaks in the wiring exist and
• whether a short to ground has occurred.

In previous vehicles, the familiar DTC button is connected electrically, e. g. to the IHKA control unit (E70/E71). In the F01/F02 on the other hand, the DTC button is connected to the ICM control unit via an electrical wire. A voltage is applied to this wire by the ICM control unit. The DTC button connects to the ground. The ICM control unit can determine by means of voltage measurement whether the DTC button is operated.

The "Driving dynamics control" function in the ICM control unit evaluates the operation of the driving dynamics switch and DTC button and uses this as the basis for determining the corresponding mode ("see FUNCTIONS" section). The ICM control unit sends signals via the bus system to inform the driver at the instrument cluster which mode has been set.

The footwell module supplies power to the center console operator control unit via terminal 58g for the locating lamp.

Valves of Steering Unit

The proportional valve that adjusts the electronic flow (EVV valve) and the Servotronic valve is activated directly from the ICM control unit. The ICM control unit contains the necessary output stages that are built up using power semiconductors.

Each valve is connected by two lines to the ICM control unit. The ICM control unit calculates the reference values for the aperture of both valves based on the road speed, steering angle and steering-angle speed input signals. These reference values are converted to a pulse-width-modulated signal that is applied at the lines leading to the valves. This means that the ICM control unit can change the aperture of the valves at any time.

Fig. 48: Identifying Steering Unit Valves

INDEX REFERENCE CHART

1. Power steering pump
2. Valve for electronic flow rate adjustment (EVV valve)
3. Servotronic valve
4. Housing of control valve for hydraulic power steering

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