Component description for regenerative braking system control unit - GF42.22-P-1100LEH

MODEL 221.095/ 195 

Phantom view of left front of vehicle 

Location 

The regenerative braking system control unit is located on the traction system hydraulic unit in the right front of the engine compartment.

Task 

General 

The regenerative braking system is a brake and vehicle dynamics control system of a modular design (only the affected functions are switched off in the event of a fault) The regenerative braking system is a further development of the Electronic Stability Program (ESP) and contains the functions of the ESP.

If the vehicle reaches the critical limits of road-holding or if a control intervention function of the controllable speed limiter (without code (494) USA version) or of cruise control is necessary, the regenerative braking system control unit causes active interventions by the brake system or interventions in the engine control.

If necessary the required wheel-individual brake pressure is calculated taking into account the "ESP", "ABS", "ASR" algorithms or the "added value functions" by the regenerative braking system control unit and adjusted in the solenoid valves of the hydraulic components. The pressure regulator adjusts the required brake pressure in each wheel.

The regenerative braking system control unit contains the control for the following systems:

• Electronic stability program (ESP)
• Acceleration Slip Regulation (ASR)
• Engine drag torque control (MSR)
• Antilock brake system (ABS)
• Brake Assist (BAS)
• Electronic Traction System (ETS)
• Tire pressure loss warning (except code (475) Tire pressure monitor (Siemens))
• PRE-SAFE
• Speed-sensitive power steering (SPS [PML])
• Cruise control
• Limiter (except code (494) USA version)
• Added value functions (SBC hold, precharging and dry braking)
• Deceleration coordination of DISTRONIC PLUS (with code (233) DISTRONIC PLUS)

Flashing 

The regenerative braking system control unit is flashable i.e. the complete software in the control unit can be updated (replaced). The software required to program the control units is stored on the STAR DIAGNOSIS DAS Update DVD.

CAN data bus 

The regenerative braking system control unit is connected to the CAN interconnection of the vehicle via the chassis CAN (CAN E) and vehicle dynamics CAN (CAN H) and exchanges data with other control units.

Input and output signals 

The following input signals are evaluated by the regenerative braking system control unit and the corresponding output signals issued:

• Direct input signals 
• Direct output signals 
• CAN input signals 
• CAN output signals 

Direct input signals 

• Terminal 30
• Terminal 87
• Terminal 31
• BAS diaphragm travel sensor (A7/7b1)
• Vacuum sensor (A7/7b3)
• Pedal angle sensor (B37/1)
• Hybrid brake light switch (S9/3)

Direct output signals 

• Stop lamp actuation via rear SAM control unit with fuse and relay module (N10/2)
• Traction system hydraulic unit (A7/3)
• Brake pressure simulator valve (Y113)
• Vacuum pump relay (+) (K109)
• Vacuum pump relay (-) (K109/1)
• SPS [PML] solenoid valve (Y10)
• Vacuum pump relay (+) (K109)
• Brake pressure simulator valve pressure sensor (B18/5)
• Left front RPM sensor (L6/1)
• Right front RPM sensor (L6/2)
• Left rear RPM sensor (L6/3)
• Right rear RPM sensor (L6/4)
• Power supply for yaw rate sensor for lateral and longitudinal acceleration (B24/15)
• Power supply for BAS membrane travel sensor (A7/7b1)
• Power supply for BAS solenoid valve (A7/7y1)
• Power supply for pedal angle sensor (B37/1)
• Power supply for brake pressure simulator valve pressure sensor (B18/5)
• Power supply for vacuum sensor (A7/7b3)
• Power supply for hybrid brake light switch (S9/3)

CAN input signals 

Yaw rate sensor for lateral and longitudinal acceleration (B24/15) 

• Yaw rate sensor for lateral and longitudinal acceleration signal

ME-SFI [ME] control unit (N3/10) 

• Engine hood closed/open

Upper control panel control unit (N72/1) 

• ESP OFF button signal (S6/2s11)

EIS [EZS] control unit (N73) 

• Ignition ON

Steering column tube module (N80) 

• Steering angle sensor signal (N49)

Central gateway control unit (N93) 

• Diagnostic CAN (CAN-D) interface

Electric parking brake controller unit (A13) 

• Electric parking brake switch (S76/15), status

CAN output signals 

Instrument cluster (A1) 

• ABS indicator lamp (A1e17)
• ESP warning lamp (A1e41)
• Multifunction display (A1p13)

Rear SAM control unit with fuse and relay module (N10/2) 

• Brake lights, taillights and left parking light signal (E3e9)
• Brake lights, taillights and right parking light signal (E4e9)

ME-SFI [ME] control unit (N3/10) 

• Wheel speed
• Requested regenerative braking torque

Wiring diagram for regenerative braking system control unit

N30/6

PE42.22-P-2101-97SAA