Electronic Stability Program Control Unit Component Description - GF42.45-P-5119FH

Model 238 

Up To Model Year 2021 

Shown on model 238.3 

Courtesy of MERCEDES-BENZ USA

Location 

The Electronic Stability Program control unit is located in the engine compartment, at the left next to the BAS brake booster (A7/7) on the traction system hydraulic unit (A7/3).

Task 

The Electronic Stability Program control unit has the following tasks:

• Reading in of sensors and signals 
• Evaluation of input factors 
• Actuation of components 
• Controlling functions 
• Output of signals 

Reading in of sensors and signals 

The input factors are read in over the following connections:

• Direct line 
• Chassis FlexRay (Flex E) 
• Vehicle dynamics CAN (CAN H) 

Direct line 

The signals from the following components are read via direct lines:

• Traction system hydraulic unit
• Brake vacuum sensor (B150)
• Left front axle rpm sensor (L6/1)
• Right front axle rpm sensor (L6/2)
• Left rear axle rpm sensor (L6/3)
• Right rear axle rpm sensor (L6/4)
• Brake lights switch (S9/1)
• Electrical parking brake switch (S76/15)

Chassis FlexRay 

The Electronic Stability Program control unit also receives information over the chassis FlexRay:

• Engine running status
• Engine speed
• Kickdown status
• Transmission mode status (transmission 725)
• Gearbox mode selector lever position (transmission 725)
• Parking Pilot status (with code 235 (Parking Pilot with PARKTRONIC))
• Driver seat belt buckle status
• Braking torque request
• Left and right front door status
• Trailer operation status (with code 550 (Trailer hitch))
• Crash signal
• Collision warning status
• Steering angle status
• Current steering wheel torque
• DISTRONIC status (with code 239 (DISTRONIC Distance Pilot) or code 23P (Driving Assistance Package))
• Steering wheel angle and steering wheel velocity
• Cruise control lever status (S40/4)

Vehicle dynamics CAN 

The Electronic Stability Program control unit also receives information over the vehicle dynamics FlexRay:

• Vehicle acceleration
• Acceleration sensor status

Evaluation of input factors 

The input factors that have been read in are evaluated by the integrated microprocessor and the relevant components are then actuated.

Actuation of components 

The Electronic Stability Program control unit actuates the following components over direct lines:

• Traction system hydraulic unit
• Left electric parking brake actuator motor (M76/1)
• Right electric parking brake actuator motor (M76/2)

Control of systems 

The Electronic Stability Program control unit controls the following systems depending on the equipment involved:

• Electronic Stability Program (ESP®)
• Electronic brake force distribution (EBD)
• Anti-lock braking system (ABS)
• Acceleration skid control (ASR), electronic traction system (ETS)
• Active Brake Assist (with code 258 (COLLISION PREVENTION ASSIST))
• Brake Assist System (BAS)
• Brake Assist System PLUS (BAS PLUS) (with CODE 23P (Driving assistance package))
• Hill Start Assist
• Flashing adaptive brake lights (except code 494 (USA version))
• Dry braking
• Precharging, depending on accelerator pedal actuation
• Precharging, depending on lateral acceleration
• HOLD function
• ESP® trailer stabilization (with CODE 550 (Trailer hitch))
• PRE-SAFE® system (with CODE 23P (Driving assistance package))
• Standstill control (SSC)
• Steer Assist (with code 23P (Driving Assistance Package))
• Tire pressure loss warning (RDW) Tire pressure monitor (with CODE 477 (Tire pressure loss warning))
• Variable speed limiter (except CODE 23P (Driving assistance package))
• Cruise control (except CODE 23P (Driving assistance package))
• Attention assistance system

Output of signals 

The signals are issued over the following connections:

• Chassis FlexRay 
• Vehicle dynamics CAN 

Chassis FlexRay 

The Electronic Stability Program control unit also sends the following signals over the chassis FlexRay:

• Wheel speeds
• Brake status
• Status of brake pedal
• ESP® status
• Tire pressure loss warning status (with code 477 (Tire pressure loss warning))
• Toothed rack force request
• Steering angle request
• Parking brake status
• Request for brake light
• Direction of travel
• Vehicle speed
• Parking Pilot driving direction request (with code 235 (Parking Pilot with PARKTRONIC))
• Standstill control status
• Targeted gear request (transmission 725)
• Engine torque request
• Attention assistance system status
• PRE-SAFE® request
• Cruise control/variable speed limiter status
• Transmission mode selection status (transmission 725)

Vehicle dynamics CAN 

The Electronic Stability Program control unit also sends the following signals over the vehicle dynamics CAN:

• Diagnosis request
• Wake-up signal

Wiring diagram for Adaptive Brake (ABR)

PE42.47-Q-2000-97DCA