Note on function of radio frequency locking/remote central locking (RFL/RCL) - AD80.35-P-2000-01B
Components
- Electronic ignition switch control module (N73)
- Electric steering column (ESC) control module (N26/5)
- Transmitter key with integrated electronics
- Overhead control panel control module (N70)
- Radio antenna
- Left front door IR receiver (A26/1) and right front door IR receiver (A26/2)
- Left/right front door lock switch (CF) (S86/1 or S87/1),
only
- Trunk lid lock switch (CF) (S88/2),
- Front driver-side door control module (N69/1) and front passenger-side door control module (N69/2)
- Driver-side signal-acquisition and actuation module (SAM) (N10/1)
The following functions are carried out by the electronic ignition switch control module:
- Radio frequency/infrared remote control
- Evaluation of radio or infrared signal
- Actuation
- of central locking (CL)
- of anti-theft alarm (ATA)
- of remote trunk release (RTR), not models 202/210 T-model
- of visual feedback via turn signal system
No locking confirmation occurs when the vehicle is unlocked or locked with the mechanical key.
The central locking and the ATA are not actuated.
- Drive authorization
- Voltage supply of key
- Reception and checking of the key's authentication value
- Enable
- of the electric steering column locking
- of the engine control as for DAS 2
Drive authorization is independent of the security status of the radio remote control or infrared remote control and the batteries in the transmitter key.
Drive authorization is enabled by the secret data exchange between vehicle key, electronic ignition switch control module, ESC control module and engine control module.
The engine control is disabled via the electronic ignition switch control module (N73). The electronic ignition switch control module (N73) is connected to the engine control module via a CAN data bus. After the engine control is disabled (key in "Ignition OFF" position), the engine control module renders the injection system inoperative.
A new electronic ignition switch control module (N73) or ESC control module (N26/5) can be installed for test purposes. The components are operated in test mode for this. The test mode is limited by a test counter.
Test mode
The components are in test mode until they are activated and can be personalized repeatedly. Before personalizing in test mode the components answer all authentication tests without checking the data received. The data is already checked after personalizing in test mode.
These processes are limited by a test counter.
Test counter
Limits the duration of test mode. The test counter counts back a value for each function call-up.
No further tests are possible if the test counter reaches the value "zero". The component is automatically activated after the value zero is reached, i.e. it is then permanently assigned to the vehicle.
The test counter status can be read out with the HHT.
Variant coding
Variant coding must be carried out with the HHT after the electronic ignition switch control module (N73) has been replaced. Variant coding is menu-assisted.
The electronic ignition switch control module (N73), the ESC control module (N26/5) and the engine control module are permanently assigned to each other by means of an identification code. For this reason the electronic part of the locking mechanism number of the lock must remain in the vehicle throughout the vehicle's service life, i.e. only the mechanical part of the locking mechanism number may change.
This means that if the electronic ignition lock control module or ESC control module is defective:
- Replace defective part and program.
This means that if a mechanical lock part is defective:
- The locking mechanism number is retained → replace lock part whilst retaining the locking mechanism number.
Revocable disabling
Disabling with a programmed workshop key or with the HHT is revocable. However, it can only be cancelled with the workshop key, not with the HHT.
Access to disabling the transmitter key via the HHT mask is as follows:
Set-up - EZS - control module adaptations - disable key
Programming the workshop key with a key programming station is menu-assisted.
Irrevocable disabling
A key can also be disabled by programming and then using a replacement key in the vehicle.
This means that if a transmitter key is lost:
- The electronic part of the locking mechanism number is retained → invalidate transmitter key by disabling.
- Change mechanical part of the locking mechanism number → fit complete mechanical locking mechanism with new locking mechanism number. It is absolutely essential to send a sticker with the 8-digit locking mechanism number, stating the VIN, to Dept. VP/AM, Mercedes-Benz AG, 70322 Stuttgart.
Disabling the key
If a transmitter key is lost, it must be disabled and the mechanical locking mechanism replaced. Disabling is possible with a programmed workshop key and with the HHT as well as by using a programmed replacement key in the vehicle.
This kind if disabling is irrevocable , as the replacement key automatically erases all the data of the "lost" key when used in the vehicle. Erasing the data and the turning enable of the key can take up to 90 minutes.
If an additional key not a replacement key is issued for a lost key, the lost key must be invalidated by disabling.
On-site programming
The following components of the drive authorization system can be programmed if a key programming station is available.
- Electronic ignition switch control module (using programmed workshop key)
- Replacement or additional key