Electronic Stability Program Control Unit, Basic Function - GF42.45-P-9890A

Model all (4xWD, CAR) 

Courtesy of MERCEDES-BENZ USA

Example illustration 

Overview 

This document contains information on:

• General 
• Function 
  • ESP control®
  • Rear axle steering

General 

The ESP® control unit processes the information required for the Electronic Stability Program (ESP®). The ESP® control unit has the following tasks:

• Read in input signals
• Evaluation of input signals
• Actuation of components

Input signals are read in through direct lines and bus lines.

Direct lines are, e.g.:

• Circuit 30
• Circuit 31
• Traction system hydraulic unit
• Pedal angle sensor
• Dual brake vacuum sensor
• Left/right front axle RPM sensor
• Left/right rear axle RPM sensor
• Brake vacuum pump relay

The ESP® control unit is a bus system user. It communicates with the following control units:

• Instrument cluster
• Supplemental restraint system control unit
• Combustion engine control unit
• Front/rear SAM control unit
• Electrical power steering control unit
• Left/right front door control unit
• Electronic ignition switch control unit
• Steering column module control unit
• Drivetrain control unit
• Electromechanical brake booster control unit

On vehicles with code 200 (conditionally automated driving), the ESP® control unit is also a participant of the redundant bus system (CAN 1 for redundancy).

The read-in input signals are evaluated by the integrated microprocessor and then the affected components are actuated.

Function 

ESP control®

The ESP® control unit chiefly contains the control for the following systems:

• Regenerative braking system
• Electric parking brake
• Radar-based regenerative braking system
• Electronic Stability Program (ESP®)
• Electronic brake force distribution
• Antilock brake system
• Anti-slip control, electronic traction system
• Brake assist
• Hill Start Assist
• Adaptive brake lights, flashing (except with CODE 494 (USA version))
• Dry braking
• Brake system precharging, depending on accelerator pedal actuation
• Brake system precharging depending on lateral acceleration
• HOLD function
• ESP® trailer stabilization
• PRE-SAFE® system
• Standstill check
• Steer Assist
• Crosswind Assist
• Tire pressure loss warning system, tire pressure monitor
• Limiter
• Cruise control
• Rear axle steering
• Electromechanical brake booster

The ESP® control unit processes these input signals and initiates, among other things, the following actuations:

• Supplemental restraint system control unit
• Electrical ignition lock control unit
• Drivetrain control unit
• Brake pedal signal
• Electric parking brake actuator motor, left/right
• Rear axle steering control unit
• Electromechanical brake booster control unit

Rear axle steering

Integrated vehicle dynamics control is implemented in the ESP® control unit. Along with control of the rear axle steering, targeted individual wheel brake interventions can also be realized here. The rear axle steering control unit also receives the calculated rear axle steering angle from the integrated vehicle dynamics control and implements the request accordingly. The dynamics function is coordinated on the rear axle steering control unit with the parking functions.