If IU is not detected, it could be due to loose connection of wires, defective IU, blown fuse, etc. It's advisable to bring your vehicle to IU service centres to get it inspected and repaired.

Here's a list of the inspection centres: https://www.onemotoring.com.sg/content/onemotoring/en/lta_information_guidelines/maintain_vehicle/inspection/other_appointed_centres.html