HERMES Control Unit, Component Description - GF82.85-P-0221GWM
Model 463 (except 463.342)
as of model year 2019
with code EK1 (HERMES communications module LTE)
Model 463 (except 463.342)
as of model year 2019
with code EM2 (Communications module (UMTS) for the use of Merced)
Shown with code EM2 (HERMES UMTS communication module)
Shown with code EK1 (HERMES LTE communication module)
Location
The HERMES control unit is connected through the head unit (A26/17) in the center console.
Tasks
The HERMES control unit is responsible for the following tasks:
- Self-diagnosis for circuit 15 ON, secures operational readiness of emergency call system by checking the following facts:
- Reception of cyclic readiness signal from Supplemental Restraint System (SRS) control unit (N2/10)
- Connection for muting audio sources
- Connection to driver hands-free system microphone (B25/20), through head unit
- Connection to emergency call system antenna 1 (A2/140) and to the emergency call system antenna 2 (A2/141)
- Reception of crash signals from the supplemental restraint system control unit (trigger signal for automatic emergency call)
- Set-up of voice or data connections to service provider
- For voice connections:
- Transmission of a mute signal to the audio sources
- Reception of signals from microphone of driver hands-free system from head unit (input)
- Sending of audio signals to the instrument cluster speaker (H4/61)
- Receiving of position data for position finding (with code EM2 (HERMES UMTS communication module))
- Forwarding of real-time traffic data from service provider to the head unit (with code EK1 (HERMES LTE communication module))
- Communication of Internet signals to the head unit (with code ZU8 (National version for the USA))
- CAN communication via diagnostic CAN (CAN D)
The HERMES control unit receives, e.g. the following signals over the diagnostics CAN:
- Circuit 15 status from electronic ignition lock control unit (N73)
- Readiness signal from Supplemental Restraint System control unit
- Crash information from Supplemental Restraint System control unit (redundant)
- Status of SOS button (N70s11) from overhead control panel control unit (N70)
- Status of Mercedes me connect button (N70s16) from overhead control panel control unit
- Control signals from controls on the multifunction steering wheel (e.g. volume control, mute, connect/disconnect)
- Steering wheel angle from the steering column tube module control unit (N80) for position finding
- Wheel speed signals and yaw rate signals from the Electronic Stability Program control unit (N30/4) for position finding
- Position data for position finding from the head unit
The HERMES control unit sends, e.g. the following signals over the diagnostics CAN:
- Check signal for the emergency call system self-test
- Map data and miscellaneous data sent by the Service Center ("Remote Information Feed") to the audio equipment (with code ZU8 (National version for the USA))
- Status signals to the instrument cluster (A1)
- Display messages for showing on the Audio/COMAND display (A40/8) to the head unit
HERMES stands for: Hardware for Enhanced Remote, Mobility & Emergency Services.
The HERMES control unit calculates the vehicle position and if necessary, it sends a message to the service center.
The HERMES control unit can send and receive for 30 days. As soon as an SMS is received, the HERMES control unit is also activated (wakeup). After 30 days the emergency call system switches into sleep mode.
Structure
The HERMES control unit contains the following components:
- Internet-compatible communication module with Bluetooth® interface and with radio interface for wireless local area network (WLAN)
- Position finding module
- GPS receiver for position finding (date, time, history and last-known location) for the listed vehicle-related services
- Memory for vehicle-specific data
- Buffer for navigation and other data that is transmitted to the vehicle
| Wiring diagram of HERMES control unit | PE82.85-P-2107-97ZHA |