Description and Operation: Description: Notes

The immobilizer system will disable the vehicle unless the proper ignition key is used, in addition to the currently available anti-theft systems such as car alarms, the immobilizer system aims to drastically reduce the rate of auto theft.

Transponder (TP) - IMMO ECU Communication

Fig 1: Overview Of Transponder (TP) - IMMO ECU Communication
Courtesy of HYUNDAI MOTOR AMERICA

TP Read Protocol
1. IMMO_ECU after IGN on (or CPU Reset cancellation) is sent Challenge to TP and confirmed Serial Number and Signature.
2. When response of input transponder is not correct, input is retry.
3. When response of input transponder is correct, The data that calculate Encryption operation in the EEPROM program compared with received data from TP.
  When Codes is same, input is finished.
  
  If the codes are not same, input are continued until when codes are same.
4. If IMMO_ECU EEPROM code is not programming, when correct transponder is inputted (CRC Check OK), input is finished.
5. After IGN1 on (CPU Reset cancellation), IMMO_ECU is reading the maximum 5 times Transponder Code
6. In the IGN1 ON&EMS_state=Lock state, when received ACKNOWLEDGE, TP is re-authenticated
  
  Fig 2: Immobilizer System Diagram
  Courtesy of HYUNDAI MOTOR AMERICA
TP/IMMO ECU/EMS Authentication Flowchart

Fig 3: TP/IMMO ECU/EMS Authentication Flowchart
Courtesy of HYUNDAI MOTOR AMERICA