The lineartronic CVT transmission is the most reliable CVT Transmission on the market and is nearly bullet proof so long the maintenance is done properly and every 50.000 km and the right CVT oil is used

What is wrong with my CVT. when the AT Temperature light is on and my car is not performing very well and it is using a lot of petrol. 

Most of the times it is caused by a fault in the hydraulic control unit which can be replaced at 30 % of the cost of a replacement unit.

Most of the workshops will tell you that the transmission needs replacing which is very expensive and they will offer you an second hand replacement.

Ask your workshop to remove the sump and check if there are any metal filings in the transmission and special on the magnet which is fitted to the Sump. If there are no metal filings ask them to replace the Hydraulic control unit and change the filter and oil.

This will take around 1 hour and the transmission needs 8=9 liters of CVT oil.

Be very careful with draining the transmission because this transmission has a separate Differential which is using a different oil. Only drain the CVT department.