Codes p1026 and p0217, hard shift second to third?

The p1026 sets when the engine coolant temperature (ECT) and cylinder head temperature 2 (CHT2) sensor readings differ by greater than a calibrated value.

The P0217 code means that the engine is or was overheating.

So, this can be the engine coolant temperature sensor needs to be replaced. here is the location I would replace the sensor and then clear the codes.

Check out the images (below). Please let us know what happens.