Kia Sedona: Description and Operation - Immobilizer System - Body Electrical System - Kia Sedona YP Service ManualKia Sedona: Description and Operation

Third generation YP (2014-2024) / Kia Sedona YP Service Manual / Body Electrical System / Immobilizer System / Description and Operation

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 possibility of auto theft.
Transponder (TP) – IMMO ECU Communication

TP Read Protocol
On IMMO_ECU, confirm the Serial Number and Signature by sending Challenge to TP after IGN on (or CPU Reset cancellation).
If response of input transponder is not correct, retry the input.
If response of input transponder is correct, decide by referring to the calculated result and the code programmed in the EEPROM.
If the codes match, input is completed.Otherwise, retry inputs until codes match.
If IMMO_ECU EEPROM code is not programmed, input is completed when correct transponder is inputted (CRC Check OK).
After IGN1 on (CPU Reset cancellation), IMMO_ECU reads Transponder Code for a maximum of 5 times.
In the IGN1 ON & EMS_state=Lock state, when Acknowledge is received, TP is re-authenticated.

Transponder / IMMO ECU / EMS authentication

Components Operations
PCM (Power Train Control Module)
The PCM (ECM) (A) carries out a check of the ignition key using a special encryption algorithm, which is programmed into the transponder as well as the PCM (ECM) simultaneously. Only if the results are equal, the engine can be started. The data of all transponders, which are valid for the vehicle, are stored in the PCM (ECM).
ERN (Encrupted Random Number) value between EMS and encrypted smartra unit is checked and the validity of coded key is decided by EMS.

The IMMOBILIZER carries out communication with the built-in transponder in the ignition key. This wireless communication runs on RF (Radio frequency of 125 kHz). The IMMOBILIZER is mounted behind the crash pad close to center cross bar.
The RF signal from the transponder, received by the antenna coil, is converted into messages for serial communication by the IMMOBILIZER device. And, the received messages from the PCM (ECM) are converted into an RF signal, which is transmitted to the transponder by the antenna.
The IMMOBILIZER does not carry out the validity check of the transponder or the calculation of encryption algorithm. This device is only an advanced interface, which converts the RF data flow of the transponder into serial communication to the PCM (ECM) and vice versa.

TRANSPONDER (Built-in keys)
The transponder has an advanced encryption algorithm. During the key teaching procedure, the transponder will be programmed with vehicle specific data. The vehicle specific data are written into the transponder memory. The writing procedure is performed only once, therefore, the contents of the transponder can never be modified or changed.

Antenna Coil
The antenna coil (A) has the following functions.
The antenna coil supplies energy to the transponder.
The antenna coil receives signal from the transponder.
The antenna coil sends transponder signal to the IMMOBILIZER.
It is located directly in front of the steering handle lock.

Schematic Diagrams
Circuit Diagram ...

Repair procedures
Teaching Procedures 1. Key Teaching Procedure Key teaching must be done after replacing a defective PCM (ECM) or when providing additional keys to the vehicle owner. The procedure starts with ...

Other Information:

Cruise Control Switch Schematic Diagrams
Circuit Diagram ...

Power tailgate opening height user setting
The driver may set the height of a fully opened tailgate by following the below instruction. 1. Confirm the position of the power door ON/OFF button is ON (not depressed). 2. Position the tailga ...


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