Terminal Control

Terminal control

The CAS generates the terminal statuses for the vehicle when the start/stop button is operated.

The terminals can only be connected when the remote control in the ignition switch is authenticated (recognized as valid) and the "key valid" signal is generated by the transponder in the CAS.

Terminal status in Vehicle Electrical System

The terminal status generated by the CAS for the vehicle is transmitted to the following buses every 100 milliseconds:

- K-CAN S
- K-CAN P
- PT-CAN
- MOST
- byteflight

The following statuses are output as telegrams:

- Status of terminal R
- Terminal 15 wake-up
- Status of terminal 15
- Status of terminal 50
- Valid key inserted

Hardware Redundancy

For safety reasons the terminal status of the terminal 15 outputs is redundant (via a hardware switch in the CAS).

Announcement of Terminal 15w "Wake-up"

The CAS and the ZGM (Central Gateway Module) are the only control units that can wake up the vehicle electrical system.

The control units on the K-CAN S, K-CAN P, byteflight and MOST are awakened by the network management (NWM) on the respective bus.

The control units on the PT-CAN are woken up via a high signal on the activation wire for terminal 15 wake-up. If a PT-CAN control unit receives the change in voltage "low-high" at the wake-up input, the control unit begins with reception and the evaluation of the messages from the PT-CAN.

Two modules (ZGM and the Power Module receive KL 15 wake-up as a hardwired input from the CAS in addition to the network management wake-up signal over the bus.

Announcement of Terminal 15 "ON"

For safety reasons certain control units and sensors are not only informed via the bus signal about terminal 15, but also have a direct hardwired output from the CAS.

The CAS provides ten KL 15 outputs for hardwire redundancies:

- Ignition coil relay: the output for the ignition coil relay is equipped with an overrun for maintaining OBD-relevant emission values (Emissions optimization). When KL 15 is switched "off" the ignition coils are not switched off until after a run-on time so that any fuel still injected is burned.
- GRS (Rotation/transverse acceleration rate sensor for DSC)
- LM/BLS (Lamp Module, brake-light switch)
- SBSR (Satellite B-pillar right, fuel pump)
- SZL (Steering Column Switching Center, selector lever transmission)
- OBD socket KL15 :supply (On-Board Diagnosis)
- Rear seat heating (has no bus line)
- Three are reserved for future use

Terminal 50 (Engine Starting)

Terminal 50 is actuated by pressing the start/stop button

Engine start-up and the related terminal change are carried out as soon as the start/stop button is pressed for at least 50 milliseconds.

The following conditions are needed to complete the start sequence:

- Remote control is valid and locked (transponder authentication).
- Brake operation: the brake is either detected via the direct wiring of the brake-light switch or redundantly via the CAN signal from the DSC . An incorrect brake signal from a defective or disconnected brake-light switch is detected as a "plausibility fault" as soon as the brake pressure is greater than 10 bar. If one of the two signals is missing, a Check Control message is sent. The engine start-up is permitted when the start/stop button is pressed again.
- Selector lever of automatic transmission in position P and N. The position of the selector lever is detected via the direct P signal or via a CAN signal. The engine can be started when at least one of these signal is present.
- No start-repeat lock present (start-repeat lock is activated at an engine speed above 1000 rpm).

If these conditions are not met, the starter-motor disabling circuit is activated. The engine cannot be started.







Starter Motor Disabling

The starter disable circuit is used to protect the starter. The starter cannot be engaged with an already running engine.

The starter disable is carried out after the actuation of the starter solenoid has been ended.

The following situations will enable the starter disable function of the CAS:

- No "brakes actuated" signal: if no "brakes actuated" signal is output within a maximum of 200 milliseconds after the start/stop button is pressed, the engine start-up is aborted again. If only one of the two redundantly output brake operation signals is received, then the engine can be started.
- No continuous "brakes actuated" signal: if during the starting procedure the brakes are not continuously actuated, the engine start-up is aborted again.
- Time-out expired: the maximum operating period of the starter is 21 seconds.
- Selector lever in invalid position: outside P or N.
- The engine speed is greater than 1000 rpm. The DME (ECM) signals "status engine running."
- Short circuit/overloading detection of the starter by the CAS.

Actuation Time of Terminal 50

The monitored actuating times of terminal 50 protects the starter against overloading. The actuation times of terminal 50 are:

- A maximum of 21 seconds. A repetition is possible immediately.
- The actuation time is reduced for each repetition by 2 seconds until the minimum actuation time of 3 seconds is reached.
- If the start/stop button is pressed for longer than the preceding actuation time, the actuation time is increased by 2 seconds again (up to a maximum of 21 seconds).

Terminal 50 E (Electronics-Signal of Starting Request to the DME)

Terminal 50 E is provided to signal the starting request by the CAS to the DME.

Terminal 50 L (Load-Starter Solenoid)

Terminal 50 L is an input to the IVM to switch on the starter solenoid.

Auto-Park, Interlock and Shiftlock Functions

Auto-Park, Interlock and Shiftlock are safety functions,

Auto-Park and Interlock are CAS functions. Shiftlock is an EGS function.

- Auto-Park: When the remote control is removed from the ignition switch, the park position of the selector lever is automatically engaged. The "Auto-Park" function is programmed in the EGS.
- Interlock: The selector lever is locked in the park position until a valid remote control can be detected in the ignition switch.
- Shiftlock: the selector lever can only be moved out of the positions P or N with the brakes actuated.

For safety reasons the EGS supplies the "transmission range and park position" signal redundantly. The EGS supplies two signals:

- The transmission position P via a direct, hard-wired cable (between the transmission and the CAS) for deactivation.
- The transmission range status via the message "gear status" as a redundancy (signal path: EGS-ZGM-CAS).