Kia Sorento: Description and Operation

Kia Sorento (MQ4, 2021-2026) Service Manual / Body Electrical System / Immobilizer System / Description and Operation

Description and Operation

•	The immobilizer system prevents vehicle theft by keeping the engine from starting without a registered key.

•	The engine starts only when the codes of ECM (Engine Control Module), BDC (Body Domain Control Unit) and smart key are identical. If the key is not the genuine key for the vehicle, the fuel supply is cut off and the engine does not start.

If the vehicle with the immobilizer is installed with a wireless remote-start system, it can cause the vehicle system malfunction and the anti-theft system can not operate.

Transponder (TP) – IMMO_BDC Communication

Body Electrical System — Immobilizer System / Description and Operation illustration

Vehicle Entry and Engine Control Procedure

•	Control Procedure During Vehicle Access

1.	If the driver carries the smart key and accesses the vehicle door, the smart key receives LF signals from the LF antenna and then sends RF signals to RF antenna.

2.	The RF antenna sends the signals to the BDC (Body Domain Control Unit). The BDC receives the signals and then instructs the UWB module to identify the smart key position.

3.	The UWB module identifies the smart key position through the UWB communication and sends the information to the BDC.

4.	The BDC instructs the PDC to unlock door based on the information from the UWB module, thereby controlling the door unlock.

•	Control Procedure During Engine Start After Vehicle Entry

1.	When the driver presses the brake pedal and the engine start button, the start and brake signals are sent to the BDC (Body Domain Control Unit) and the BDC operates the LF antenna.

2.	The LF antenna sends key data LF signals. The smart key receives the LF signals and then sends the RF signals to the RF antenna.

3.	The RF antenna sends the signals to the BDC. The BDC receives the signals and then instructs the UWB module to identify the smart key position.

4.	The UWB module identifies the smart key position through UWB communication and then sends the information to the BDC.

5.	The BDC authenticates through the K-Line (Immobilizer) communication with the ECM. If the data matches, the engine starts.

Key Registration Procedure: SMK(FOB Key) & Non SMK(Folding Key)

SMK(FOB Key)

Body Electrical System — Immobilizer System / Description and Operation illustration

Non SMK(Folding Key)

Body Electrical System — Immobilizer System / Description and Operation illustration

•	During the key registration procedure, if two keys are placed too close together, a communication error can occur and the key cannot be registered correctly. Therefore, the distance between keys must be kept.

•	During the key registration procedure, if the key coding time displayed on the KDS screen (5 seconds) is exceeded, the key cannot be registered correctly. Be sure to comply with the designated time.

•	If the key is dropped or receives an impact, it can cause damage to the built-in transponder (TP), which can result in the engine not starting. Therefore, carefully handle the key.

1.	Refer to adjustment procedure for the key registration. (Refer to Immobilizer System - “Adjustment")

Immobilizer System

...

On Vehicle Inspection. Adjustment

On Vehicle Inspection On Vehicle Inspection Diagnostic With KDS 1. The body electrical system driving ...

Kia Sorento: Description and Operation

See also:

Manuals list