CLA 180 - Engine management light - Danboy2013

I recently bought a CLA180 AMG SPORTS. It’s a year 2013. I was driving on a nice sunny day with the air condition on and suddenly the engine management light came on. I carried out a diagnostics and error code P0128 came up. It reads:

Coolant Thermostat {Coolant Temperature Below Thermostat Regulating Temperature). I cleared the error codes and it was fine for a few days until I decided to drive with the air condition again. Please does anyone know what is going on here? Thanks

CLA 180 - Engine management light - elekie&a/c doctor

Hopefully you have checked the engine coolant level first. If this is ok,then I would suspect a fault with the electronic thermostat system.