Follow either of these procedures:
Kia Cee'd JD Service Manual: Catalytic Converter Description and operation
Description
The catalytic converter of the gasoline engine is a three way catalyst. It oxidizes
carbon monoxide and hydrocarbons (HC), and separates oxygen from the oxides
of nitrogen (NOx).
...
Kia Cee'd JD Service Manual: Troubleshooting
Troubleshooting
Ignition System
Symptom
Suspect Area
Remedy
Engine will not start or is hard to
start (Cranks OK)
Ignition lock switch
Inspect ignition lock switch, or replace as requ ...