I have narrowed my problem down to the excessive oscillation of the basket drum, which then interferes with the temperature sensor that is attached to the rear casing. In normal operation, the basket should oscillate less (or be firmer) so that the amplitude does not interfere with the position of the sensor. I confirmed this by applying pressure to the basket and it was a lot more wobbly than the functioning front-load washer in my other investment property. Also, the washer can finish a small load cycle because there is less weight compounded with water but not a full load (more weight --> more wobbling --> sensor interference --> cycle disruption/error). But even when it finishes, the clothes are not drained of excess water, which I also think is consistent with excessive oscillation.
I did some research and found that it could be two parts that control/limit the wobbling of the basket drum: the suspension spring above it or the shock absorber underneath. My question is, which of these two, or another third part is most likely responsible for this defect?