DTC P1676: Immobilizer-Smartra Message Error: General Description
WARNING: This page is about a different car, the 2017 Kia Soul EV. However, it is still accessible from the selected car via links, so may be relevant.
The VMCU controls the Drive motor, in a normal way for starting and running, and starts communication with the Smart Key Unit, sending a PIN request to the Smart Key Unit and waiting for valid release message from it until the release time period has ended. In case of Smart Key Unit immobilizer function is locked, the Smart Key Unit answer is the no release message.
VMCU enters in the locked state, which causes the activation of the immobilization actions of the engine. In case of Smart Key Unit immobilizer function state is released, the Smart Key Unit answer is the release message, including the information Smart Key Unit unlearned mode and the PIN code.