Gasoline Version

The Immobilizer System containsa device with an integrated coil, termed ‘Active Antenna’, the crypto transponder, and the engine management system (EMS).

The Active Antenna is attached at the ignition lock and performs the following tasks :

  • supplying power to the transponder
  • receiving data from the EMS and transmitting it to the transponder
  • receiving and demodulating data from the transponder, transmitting it to the EMS

All of these tasks are managed by the EMS

Diesel Version

The Immobilizer System is made up of of an electronic device with integrated coil, similarly called ‘Active Antenna’, the ignition key-integrated crypto transponder, and the Immobilizer-Control-Unit (ICU).

The Active Antenna is attached at the ignition lock and performs the following tasks:

  1. supplying power to the transponder
  2. receiving data from the ICU and transmitting it to the transponder
  • receiving and demodulating data from the transponder, transmitting it to the
  1. ICU

All of these tasks are managed by the ICU.

System Integration

One model of the immobilizer, the med 98.2, allows the engine to start once a particular authorization is given during the start-up. This immobilizer gives permission for the engine to start by driving ON an internal solenoid valve. Likewise, it prohibits start-up by keeping that valve OFF.

The med 98.2 is a solo unit assimilating a subsystem which:

  • utilizes a valve that permits (open) or blocks (closed) the fuel to flow through the engine
  • a microprocessor which controls and activates the valve during engine start-up.This allowsengine use only once a specific permission is given.

This unit is also equipped with a basic set of parts that work to reduce the system’s dependence on the microprocessor. Apart from a brief moment during start-up, this unit allows the system to open the valve, but not to close it.

Deactiviating the KL 15 is the only method to shutting off the valve.

This characteristic allows for an optimal degree of safe operation. In the even that the microprocessor fails, the unit does not cause the valve to close. The basic result of this failure is a prevention of any proceeding engine start-ups.

characteristics show that med 98.2 immobilizer can only serve as a fully functional anti-theft device when used simultaneously with a control device, such as the ICU. When entreated, the ICU sends a previously-selected coded message to the med 98.2. Based upon this message, the med 98.2 allows or disallows the engine to start.

Though primarily an immobilizer, the med 98.2 also performs several diagnostic services when additional hardware is attached. External test instruments, such as SCAN-100, can be connected to the immobilizer to help provide this service.



The immobilizer system is a theft deterrent system that determines whether or not to disable starting of the hybrid control system depending on a comparison of the key’s ID code and the vehicle’s pre-registered code. The immobilizer system compares the vehicle transponder key ECU’s pre-registered ID code with the key-embedded transponder chip’s ID code. If the ID codes do not match, the immobilizer system activates and the hybrid control system cannot be started. The transponder key ECU manages communication with the hybrid vehicle control ECU and power source control ECU. When the ID codes of the transponder chip and transponder key ECU match, the transponder key ECU authorizes the starting of the hybrid control system.


Starting hybrid system with key inserted into the ignition:

When the ECU in a hybrid system detects that the ignition key is turned to ON, the ECU produces a faint electrical wave, providing power to the transponder key coil. Once the key receives the faint pulse, the transponder chip gives out a key identification code. The key coil reads this code and it is amplified and transmitted to the ECU. If this code matches the previously programmed code, then the ECU switches the security indicator off, allowing the power button to be pressed and subsequently authorizes power in the vehicles various relays. .

The ACC, IG1, and IG2 relays all turn on. This signal turns the power switch’s color to amber, letting the driver know that they have properly authorized the automobile to start. The power source control ECU then sends a start-up signal to the hybrid control ECU. This code is confirmed and verified. If all of this is successful, the ECU bypasses the immobilizer and the hybrid control system starts up.

Starting hybrid system without key inserted

into the ignition:

Hybrids allow for the driver to start the car without inserting a key into the ignition. A certification output of the ECU accomplishes this, requesting a signal to the room oscillator. The room oscillator emits a signal that produces an area of detection within the vehicle. The key sends its code to the ECU via a receiver in the door. This certification code is meant to match the previously agreed upon code within the ECU transponder. If it does, the ECU switches the security indicator to ON. When the driver then pushes the power button, these matching results are transmitted to the power control ECU, authorizing the transition of the power modes. The relays all switch ON and supply power to the various power modes. At this point, the system turns the power button’s light color to amber, telling the driver the authorization was successful. Then the power source ECU transmits the all-go signal to the hybrid vehicle control ECU, which confirms the code. Once all these steps have successfully been accomplished, then the immobilizer is bypassed and the hybrid control system starts up.