Smart Key ECU (SMK ECU)

WARNING: This page is about a different car, the 2016 Hyundai Elantra GT and 2015 Hyundai Elantra GT. However, it is still accessible from the selected car via links, so may be relevant.

The SMK ECU manages all functions related to "Passive Unlock", "Passive Lock" and "Passive Authorization for Engine Start Operation".

It reads the inputs (Push button in door handle, Start Stop Button (SSB), PARK position Switch), controls the outputs (e.g. exterior and interior antennas), and communicates via the CAN/LIN (depends on the vehicle) as well as a single line interface to further devices of the car.

It reads the inputs (Push button in door handle, Start Stop Button (SSB), PARK position Switch), controls the outputs (e.g. exterior and interior antennas), and communicates via the CAN as well as a single line interface to further devices of the car.

For communication with the SMART KEY FOB, SMK ECU generates a request (challenge) as an encoded and modulated 125 kHz signal at the inductive antenna outputs and receives the SMART KEY FOB's response via the external RF receiver.

The main functional blocks of the SMK ECU are:

Power supply
Microcontroller with FLASH Memory
Single Line Interface to SRX
Single Line Interface to EMS
Input stage
LF antenna Amplifier/Driver
CAN communication with BCM
LIN communication with other unit (depending on platform)

The LF antenna Amplifier/Driver generates a 125 kHz sinusoidal carrier signal which is distributed to the different antennas.