Keyless Starting System: Description and Operation

Passive start - Keyless vehicle module (KVM)

Passive starting
Passive start can be initiated in different ways. The system receives an indication that the vehicle is about to be started when one of the following occurs:
- the key-in switch in the ignition switch is closed
- a signal is received from the central electronic module (CEM) indicating that the brake pedal has been pressed (automatic transmissions)
- clutch switch (manual transmissions).

Hint: If the clutch pedal is not depressed (switch not affected) when a start is attempted a request for a text message is sent to the Driver information module (DIM) that the clutch pedal is not depressed.
On vehicles equipped with DSTC an automatic message that DSTC is engaged is displayed for 5 seconds at a start attempt. This message has higher priority than the message about the clutch pedal. The message that the clutch pedal is not pressed is therefore shown after 5 seconds.

The switch at the clutch pedal or brake pedal is used as early as possible so that the passenger compartment can be scanned for keys. The driver naturally presses the clutch or brake pedal before starting. This means that the reaction time from initiation to start is reduced.
When a scan for a key begins, the internal antennas are activated and a request is transmitted. Keyless entry keys will reply in order, transmitting their identity number and codes. The keyless vehicle module (KVM) compares these codes with its own codes. As soon as a received code matches a programmed code, the key is validated and scanning will stop.
The keyless vehicle module (KVM) then sends an encrypted message to the central electronic module (CEM) that an approved key has been detected and validated. This validation takes a predetermined amount of time.
If the starter button is then turned from position 0 to I, II or III, the central electronic module (CEM) deactivates the immobilizer system, allowing the engine to start. If the starter button is not turned from 0 to 1 within a predefined time, the validation of the key will expire. If the key-in switch or a pedal switch is then reactivated, the system will scan for keys again.