It shows instantaneous change of the turbo boost pressure.
Kia Cee'd JD Service Manual: Rear Pillar Trim Components and components location
Component Location
[5Door]
1. Rear pillar trim
[3Door]
1. Rear pillar trim
...
Kia Cee'd JD Service Manual: Crash Pad Center Panel Components and components location
Component Location
1. Crash pad center lower panel
...