Position Determination Of Transmitter Key, Basic Function - GF80.20-P-1009A
Model all (4xWD, CAR)
Overview
This document contains information on:
- General
- Function
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.
Function
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 KEYLESS-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
The transmitter key receives signals from the vehicle from a distance of six meters. The vehicle remains locked while the transmitter key is between three and six meters from the vehicle. However, personalized settings are already being transmitted and, depending on the equipment installed, the retractable door handles extend outward. If the distance to the key reduces further, and the key is in zone 3 for longer than two seconds, the vehicle is unlocked.
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.
The wireless connection between the key and the vehicle is stopped if it takes longer than 2 minutes for the key to switch from zone 2 to zone 3. Smart unlock is no longer available after 1-2 minutes in zone 3. If the key leaves the 6 meter detection range within 5 minutes of the end of a journey, the wireless connection is stopped immediately. However, if the key stays inside the detection range for 72 hours, the transmission strength of the vehicle is halved and the total detection distance is reduced from 6 meters to 4.20 meters. The wireless connection is stopped after 408 hours inside the detection range. The vehicle must then be actively unlocked to restart the wireless connection.
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 KEYLESS-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 | PE80.20-P-2503-97A | |
| Model 293 | PE80.20-P-2503-97B | ||
| Model 206, 223, 254, 295, 296, 297 | PE80.20-P-2503-97C | ||
| Model 213, 238, 257, 290 as of Model year 2021 | PE80.20-P-2503-97E | ||
| Model 464 | PE80.20-P-2503-97F | ||
| Model 232 | PE80.20-P-2503-97G | ||
| Additional basic functions | |||
| Electronic ignition lock control unit, basic function | GF80.57-P-9890A | ||
| KEYLESS-GO control unit, basic function | Model all (CAR) | GF80.61-P-9891A | |
| Transmitter key, basic function | GF80.35-P-2001A | ||
| KEYLESS-GO antenna, basic function | GF80.61-P-2001A | ||
| Rear switch module, basic function | Model all (CAR) with code 871 (Sensor system for trunk lid opening/closing) |
GF80.61-P-9890A |