Blind Spot Assist, Function - GF54.71-S-0003TRA
Model 447.6/7/8
With Code JA7 (Blind Spot Monitoring)
Model 448.8
With Code JA7 (Blind Spot Monitoring)
Shown: model 447.8 (with engine 651)
Shown on model 447.6/7 (with engine 622, 651
Function requirements, general
- No undervoltage or overvoltage
- "Blind Spot Assist" activated in "Assistance" menu in instrument cluster (IC) control unit
- Engine running or drive train operational
- Vehicle moving forward
- Vehicle speed: v ≥ 30 km/h
- No trailer operation (with CODE Q50 (Trailer hitch with removable ball head) or with CODE Q22 (Trailer hitch with non-removable ball head))
- Soiling and function test on radar sensor system completed successfully
Object recording (e.g. passing vehicle) via the radar sensor system is based on the radar measuring procedure.
The right rear Blind Spot Assist radar sensor and the left rear Blind Spot Assist radar sensor perform a soiling and function test each time the engine is started in order to ensure that they are functioning correctly. The function test requires an object to be located in the respective detection area (this object is used as a reference value). If a malfunction is detected or no objects (for the function test) are present in the detection range, the Blind Spot Assist cannot be activated. The right rear Blind Spot Assist radar sensor receives the signals from the left rear
The visual warning output takes place via the following components:
- Left Blind Spot Assist readiness and warning indicator
- Right Blind Spot Assist readiness and warning indicator
- Blind Spot Assist warning indication in the multifunction display (via the "Blind Spot Assist" menu)
Blind Spot Assist radar sensor via the front end CAN. The right rear Blind Spot Assist radar sensor evaluates these signals in combination with its own signals and, if functioning correctly, sends the "Radar sensor system operational" status via the front end CAN to the electronic ignition lock (EIS) control unit.
Blind Spot Assist, general
The Blind Spot Assist monitors the rear and side areas of the vehicle using short range radar and, if necessary, informs the driver that an intentional lane change (turn signal light active) is not recommended at this time. In a broader sense, the Blind Spot Assist acts as an extension of the outside mirrors and inside rear-view mirror. It does not release the driver of his/her obligation to perform lane changes safely on his/her own responsibility.
When the "Blind Spot Assist" menu is selected, a warning message (vehicle with Blind Sport Assist and vehicle detected in left or right blind spot) is shown in the multifunction display of the instrument cluster (IC) control unit in addition to the warning indications in the left and right outside mirrors.
The acoustic warning is output via the instrument cluster speaker that is directly actuated by the instrument cluster (IC) control unit. If a risk of collision is detected with vehicles that are in the blind spot, then an accident can be avoided or the consequences of the accident lessened.
The area which cannot be seen in the left or right outside mirror and inside rearview mirror is monitored by the following components:
- Right rear Blind Spot Assist radar sensor
- Left rear Blind Spot Assist radar sensor
The right rear Blind Spot Assist radar sensor reads in the signals from the left rear Blind Spot Assist radar sensor via the front end CAN and evaluates them.
Illustration of the Blind Spot Assist principle
The following information is evaluated by the right rear Blind Spot Assist radar sensor:
- Terminal status 15
- "Blind Spot Assist" status
- Engine running or drive train operational
- Vehicle moving forward
- Vehicle speed
- Engaged gear range (with transmission 722.9)
- Brake status
- Status of trailer recognition (With Code Q50 (Trailer hitch with removable ball head) or With Code Q22 (Trailer hitch with non-removable ball head))
Circuit 15 status:
The electronic ignition lock (EIS) control unit sends the circuit 15 status via the front end CAN to the right rear Blind Spot Assist radar sensor.
Blind Spot Assist status:
Model 447.8, model 448.8
The instrument cluster (IC) control unit sends the status of the Blind Spot Assist via the user interface CAN, gateway for the user interface CAN, electronic ignition lock (EIS) control unit and the front end CAN to the right rear Blind Spot Assist radar sensor.
Model 447.6/7
The instrument cluster (IC) control unit transmits the status of the Blind Spot Assist via the chassis CAN, electronic ignition lock (EZS) control unit and front end CAN to the right rear Blind Spot Assist radar sensor.
Engine running or drive train operational:
The CDI control unit or ME-SFI control unit (N3/34) (with engine 274) sends the "Engine running" or the "Drivetrain ready" signal via chassis CAN, electronic ignition lock control unit (EZS) and front end CAN to the right rear Blind Spot Assist radar sensor.
Vehicle moving forward:
Forward movement is defined via the wheel rotation direction. The Electronic Stability Program (ESP) control unit sends the wheel rotation direction via the chassis CAN, electronic ignition lock (EIS) control unit and the front end CAN to the right rear Blind Spot Assist radar sensor.
Vehicle speed:
The vehicle speed is calculated from the wheel speed. The Electronic Stability Program (ESP) control unit sends the vehicle speed via the chassis CAN, electronic ignition lock (EIS) control unit and the front end CAN to the right rear Blind Spot Assist radar sensor.
Engaged gear range (with transmission 722.9):
The fully integrated transmission control (VGS) control unit sends information about the engaged gear range via drive train CAN, CDI control unit or ME-SFI control unit, chassis CAN, electronic ignition lock (EIS) control unit and front end CAN to the right rear Blind Spot Assist radar sensor.
Brake status:
The Electronic Stability Program (ESP) control unit sends the brake status via the chassis CAN, electronic ignition lock (EIS) control unit and front end CAN to the right rear Blind Spot Assist radar sensor.
Status of trailer recognition (With Code Q50 (Trailer hitch with removable ball head) or With Code Q22 (Trailer hitch with non-removable ball head)):
If a trailer is detected the trailer recognition control unit [AAG] sends the "Trailer detected" status via the interior CAN electronic ignition lock (EIS) control unit and front end CAN to the right rear Blind Spot Assist radar sensor.
The Blind Spot Assist system includes the following subfunctions:
- Measuring procedure function sequence
- Function sequence for system and warning messages
Measuring procedure function sequence
Vehicles are detected based on the radar measuring procedure. The radar sensors emit bundled electromagnetic waves as "primary signals". If these waves hit an object (vehicle in the blind spot), they are reflected by it and received again by the corresponding radar sensor as a secondary signal. These signals are used to calculate the distance and the speed of the detected object as well as its angle relative to the vehicle.
The right rear Blind Spot Assist radar sensor reads in the signals from the left rear Blind Spot Assist radar sensor via the front end CAN and evaluates them.
The detection ranges of the radar sensor system are based on the angle at which the radar waves are emitted They are extrapolated by the right rear Blind Spot Assist radar sensor to produce the actual monitoring ranges.
Illustration showing rear monitoring range
Function sequence for system and warning messages
When circuit 15 is switched on the left and right Blind Spot Assist readiness and warning indicators light up red until the CDI control unit or ME-SFI control unit sends the "Engine running" or "Drivetrain operational" signal. Additionally, when the "Assistance" menu is switched on in the instrument cluster (IC) control unit, the readiness of the Blind Spot Assist is indicated in the multifunction display of the instrument cluster (IC) control unit (in the multifunction display, gray radar waves appear spreading toward the rear next to the vehicle). If system errors are detected, a corresponding fault message appears instead of the readiness indicator.
The request to issue system and warning messages is sent by the right rear Blind Spot Assist radar sensor via the front end CAN, electronic ignition lock (EIS) control unit and interior CAN to the left or right front door control unit which then actuates the corresponding left or right Blind Spot Assist readiness and warning indicator.
The right rear Blind Spot Assist radar sensor also transmits the request to output system, error and warning messages in the instrument cluster (IC) control unit via:
- Model 447.8, model 448.8
- Front end CAN, electronic ignition lock (EZS) control unit, chassis CAN, gateway for user interface CAN and user interface CAN to the instrument cluster (IC) control unit.
- Model 447.6/7
- Front end CAN, electronic ignition lock (EZS) control unit and chassis CAN to the instrument cluster (IC) control unit.
If, at a speed of v ≥ 30 km/h, a vehicle is located in the radar sensor system detection range, the driver receives a warning by means of illumination of the red left or right Blind Spot Assist readiness and warning indicator in the left or right outside mirror on the side of the vehicle on which the vehicle is in the blind spot. Additionally, a warning is shown in the multifunction display of the instrument cluster (IC) control unit. When vehicles are passing, they are recognized and a warning is issued regardless of their relative speed to the vehicle with Blind Spot Assist. Due to the short reaction time when the difference in speed is high, the warning message output sometimes does not have any added value. If, despite illumination of the left or right Blind Spot Assist readiness and warning lamp, the driver still attempts to change lane and indicates this by operating the combination switch (turn signal light active), a double warning tone is additionally issued once by the instrument cluster speaker. The left or right Blind Spot Assist readiness and warning indicator flashes. If the vehicle leaves the detection range of the radar sensor system, the left or right red flashing Blind Spot Assist readiness and warning indicator is switched off.
The steering column tube module (MRM) control unit reads in the switch position of the combination switch directly and sends it via the chassis CAN, electronic ignition lock (EIS) control unit and front end CAN to the right rear Blind Spot Assist radar sensor.
Blind Spot Assist warning indication (in the outside mirror), shown on left outside mirror
The following table contains the requirements for displaying system readiness and for showing the visual warning messages:
| Operating state | Blind Spot Assist warning indicators in left or right outside mirror "OFF" | Blind Spot Assist readiness indicator in instrument cluster (IC) control unit, function status "ON" | Blind Spot Assist readiness indicator in instrument cluster (IC) control unit, function status "Operational" | Blind Spot Assist warning indicator in left or right outside mirror lights up red | Blind Spot Assist warning indicator in left or right outside mirror flashes red |
|---|---|---|---|---|---|
| "Tml. 15 OFF" | X | ||||
| "Circuit 15 ON" | X | ||||
| Engine running or drive train operational | X | ||||
| Blind Spot Assist activated via instrument cluster (IC) control unit | X | ||||
| Vehicle accelerates, vehicle speed v ≥ 30 km/h | X | X | |||
| Vehicle decelerates, vehicle speed v ≤ 25 km/h | X | X | |||
| Trailer detected (with CODE Q50 (Trailer hitch with removable ball head) or with CODE Q22 (Trailer hitch with non-removable ball head)) | X | ||||
| Gear range "R" engaged (with transmission 722.9) | X | X | |||
| Vehicle recognized in blind spot | X | X | |||
| Turn signal light active, vehicle detected in blind spot | X | X | |||
| Fault detected | X |
| Electrical function schematic, blind spot assistant | Model 448.8 with code JA7 (Blind Spot Monitoring) | PE54.71-S-2051-97VDA | |
| Model 447.8 with code JA7 (Blind Spot Monitoring) | PE54.71-S-2051-97TRA | ||
| Model 447.6/7 with code JA7 (Blind Spot Monitoring) | PE54.71-S-2051-97TRB | ||
| Overview of system components for driver assistance systems | Model 447.6/7/8 with code JA7 (Blind Spot Monitoring) except code XM0 (Facelift) Model 448.8 with code JA7 (Blind Spot Monitoring) |
GF54.00-S-9998TRA |