Description And Operation
DESCRIPTION
The Electronic Steering Lock (ESL) system consists of the following components:
- Body Control Module (BCM)
- Electronic Steering Lock (ESL)
- Keyless Ignition Node (KIN)
Vehicles manufactured for Europe-Middle East-Africa (EMEA) markets only have an electromechanical device called an ESL that locks (key OFF) and unlocks (key ON) the steering upon request by the BCM. The steering lock module is located on the steering column in the same position where the ignition switch would be found. The ESL is only present on cars with FOBIK-type key and the KIN module (Start/Stop button). Cars with a key with groove have the classic mechanical steering lock.
The ESL module transmits data and communicates with the other modules involved in the Sentry Key Immobilizer System (SKIS) via CAN-C.
In normal operating conditions the ESL module unlocks the steering column if, and only if, the FOBIK in the vehicle is identified by the SKIS as a valid key.
OPERATION
The Radio Frequency Hub (RFH) and the ESL module are no longer linked electronically. During servicing, one can be replaced independently of the other.
Steering column locking
Before sending the steering locking request to the ESL module, the BCM checks the following parameters:
- Ignition status: the transition from ON or ON with engine running to OFF must be detected.
- Driver side door status: the transition from driver side door closed to driver side door open must be detected.
- For versions with automatic transmission only. Automatic transmission status: the transmission must be in Park ("P").
If one of the three conditions is not satisfied, the BCM will not send the steering column locking request to the ESL module.
If the vehicle has a manual gearbox, the BCM will only check the first two parameters (ignition status and driver side door status). If they are satisfied, the ESL module will lock the steering column when the vehicle speed is below a minimum threshold.
The ESL module receives the vehicle speed signal from the Anti-lock Brake System (ABS) module. The acquisition of the vehicle speed signal continues even after the ignition switch is turned to "OFF".
Steering column unlocking
When the BCM receives the information that the Stop/Start button has been pressed from the RFH, it requests that the RFH carry out key recognition. If the key is identified as a valid key, the BCM will send a steering column unlocking request to the ESL module. If instead the key is identified as an invalid key or missing key, the BCM will not send any steering column unlocking request.
Body Control Module
Inputs
- Key ON/OFF diagnostic procedure status
- Driver door status
- Key-in ignition status from KIN
- Key selector position
- Operational mode status
- Transponder authentication status
- ESL unlock_RS request
- ESL control encoding response
- ESL mini-cryptG coding response
- ESL feedback command response
- ESL lock fail status
- ESL unlock fail status
- Code check status - steering lock status
Outputs
- ESL control encoding request to ESL
- ESL mini-cryptF coding request to ESL
- ESL mini-crypt_rnd request to ESL
- ESL lock/unlock request to ESL
- ESL Lock/unlock fail status to CAN
- Intrusion attempt status to CAN
- ESL Lock/unlock fail status indication to IPC
- Move steering wheel message to IPC
Electronic Steering Lock
Inputs
- Key-in ignition status from BCM
- Vehicle speed signal from ABS
- Vehicle speed signal fail from ABS
- Vehicle speed signal
- INT relay status
- Key selector position
- CRC and Message Counter fail status info
- ESL control encoding request from BCM
- ESL mini-cryptF coding request from BCM
- ESL mini-crypt_rnd request from BCM
- ESL lock/unlock request from BCM
- Steering lock motor status from motor sensor
Outputs
- ESL control encoding response to BCM
- ESL mini-cryptG coding response to BCM
- ESL code check status of steering lock status to BCM
- ESL lock/unlock fail status to BCM
- ESL feedback command
- Steering lock command to motor
Keyless Ignition Node
Outputs
- Key selector position
- Key-in ignition status