Unless you have a decent scanner you won't pull codes for the transmission computer. You could have some stored and no engine light. Basically no scanner/code reader that only reads obdII codes will be of any help. Unless you get something between $500-1000.
Does the car shift up and down all the time at all different speeds? Mine is kinda all over the place on the freeway around 50mph and doesn't want to up shift to drop rpm until it's good and warm which usually takes 20 mins in our ****ty weather.
Do you not have any powertrain warranty?
Mirage videos:
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View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)