The ESP control unit (N30/4) reads the following components and signals:
Brake light switch (S9/1), this is required for detection and evaluation of the switch position of the dual contact switch (normally open and closed contacts) when actuating the brake.
The rpm sensor, left front (L6/1), rpm sensor, right front (L6/2), rpm sensor, left rear (L6/3) and rpm sensor, right rear (L6/4), these supply the current wheel speed signals from the respective wheels.
ESP brake pressure sensor (B34), this detects actuation of the brake by the driver and records the brake pressure.
"ASR OFF" switch (N72/1s5), this records the driver request "Switch off acceleration slip regulation (ASR)" when the "ASR OFF" switch (N72/1s5) is pressed.
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The yaw rate and lateral acceleration sensor (B24/15), this detects the vehicle yaw rate about the vertical axis.
The brake pad contact sensor, left front (S10/1), brake pad contact sensor, right front (S10/2), brake pad contact sensor, left rear (S10/3) and brake pad contact sensor, right rear (S10/4), these determine the brake lining wear.
Steering angle sensor (B24/8), this recognizes the motion of the steering wheel.
Whichever of the following engine control units is installed:
- CDI control unit (N3/9) (on engine 646.982/983)
- ME-SFI [ME] control unit (N3/10) (on engine 112)
- CDI control unit (N3/20) (on engine 642)
- CDI control unit (N3/26) (on engine 646.980/981)
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The engine control unit forwards the Controller Area Network (data bus/CAN bus) (CAN) messages "Engine torque" and "Accelerator pedal position". The "accelerator pedal position" CAN message is used to record the engine torque required by the driver.
The ETC [EGS] control unit (N15/3) (with transmission 722.6), this transmits the CAN message "transmission ratio", which indicates the currently engaged gear.
The ESP control unit (N30/4) prepares these signals and evaluates them. A differentiation is made for the evaluated data, between data for specifying the relevant physical quantity, the calculation of additional physical quantities, which are required for calculating control functions, and information for describing the switching status of a switch or sensor.
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The ESP control unit (N30/4) calculates the following values:
Acceleration
Deceleration
Wheel slip
Drive slip
Decel slip
These values are required for implementing the control functions of the following control systems:
Electronic Stability Program (ESP)
Antilock brake system (ABS)
Electronic Traction System (ETS)
Brake Assist (BAS)
Acceleration Slip Regulation (ASR)
Electronic brake force distribution (EBV)
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Depending on the control functions in question, the following components are actuated by the ESP control unit (N30/4):
The traction system hydraulic unit (A7/3).
The ESP indicator lamp (A1e14) and the ABS indicator lamp (A1e16) integrated in the instrument cluster (A1).
The respective engine control unit, which intervenes in the engine management system.