Position Determination Of Transmitter Key, Basic Function - GF80.20-P-1009A
Model all (CAR)
Overview
This document contains the following information:
- General
- Operating principle
General
The drive authorization system uses the position determination to determine exactly where the transmitter key is located. Start enable is granted only if the transmitter key is located in the vehicle interior.
Start enable must not be granted if the transmitter key is located outside the vehicle. This prevents children in the vehicle from setting the vehicle in motion when the driver has left the vehicle (with the transmitter key), for example.
Vehicles with KEYLESS-GO
The position of the transmitter key must also be determined accurately outside the vehicle.
Vehicles with vehicle access and drive authorization via mobile phone
Where the digital vehicle key (mobile phone or digital vehicle key sticker) is used, the start enable is only granted if it is placed in the stowage compartment/tray in the center console.
Operating principle
The position search for the transmitter key is activated when the driver requests start enable. An antenna in the vehicle interior transmits radio signals. They are received by the transmitter key. The antenna and the transmitter key then exchange encrypted data. If the transmitter key is not located in the vehicle interior, the start enable is not issued.
Vehicles with KFYI FSS-GO
The position search for the transmitter key is also activated when the following actions are performed:
- Open door
- Open trunk lid or liftgate
- Lock or unlock vehicle via the central locking system
If the transmitter key is not located near the vehicle, it remains locked, for example. Multiple antennae located at the side, front, and back of the vehicle transmit radio signals. The transmitter key receives the signals from the antenna located near it. This antenna and the transmitter key then exchange encrypted data. The position of the transmitter key is verified by evaluating the signal levels of the radio signals and can thus be determined accurately.
If the vehicle is loaded with a large percent by volume of metal, the radio signals emitted by the antennae may be strongly reflected or absorbed. This can cause incorrect detections. In vehicles with KFYLFSS-GO, the maximum overlap between the inside and outside areas (measured at the side window) is approx. 10 cm depending on the vehicle contour. This means, the transmitter key is definitely located inside or outside the vehicle above 10 cm. At less than 10 cm (gray zone), the transmitter key position determination may be faulty.
| Function schematics | |||
| Function schematic for detection of transmitter key position | Model 118, 177, 247 Model 167 Model 243 |
PF80.20-P-2503-97A | |
| Model 293 | PF80.20-P-2503-97B | ||
| Model 206, 223, 295, 297 | PF80.20-P-2503-97C | ||
| Model 213, 238, 257, 290 as of model year 2021 | PF80.20-P-2503-97F | ||
| Control units | |||
| Electronic ignition lock control unit, basic function | GF80.57-P-9890A | ||
| KFYLFSS-GO control unit, basic function | GF80.61-P-9891A | ||
| Components | |||
| Transmitter key, basic function | GF80.35-P-2001A | ||
| KFYLFSS-GO antenna, basic function | GF80.61-P-2001A | ||
| Component descriptions | |||
| Transmitter key, component description | Model 223 | GF80.57-P-6010A | |
| Model 243 | GF80.57-P-6010B | ||
| Radio frequency transmitter, component description | Model 223 with code 889 (KFYLFSS-GO) Model 223 with code 942 (Load compartment/trunk package) |
GF80.61-P-2004A | |
| Rear switching module, component description | Model 223 with code 871 (Sensor system for trunk lid opening/closing) |
GF80.61-P-4110A | |
| Keyless-go antenna, component description | Model 223 | GF80.61-P-4202A | |
| Model 243 | GF80.61-P-4202B |