یدک‌کشی یا بار سنگین مداوم

The transmission is being worked harder than its cooling can keep up with, and reporting heat rather than a fault.

This is on the list because it is a real cause and because it is the one that is not broken. Towing, a fully loaded vehicle, a long climb, or heavy traffic on a hot day all put more energy into the fluid than a normal drive, and a torque converter that is not locked up is a fluid coupling turning the difference into heat.

The pattern is the diagnosis. Temperature codes that appear on a trailer trip or a mountain pass and never in ordinary driving are describing the duty rather than the gearbox. Codes that appear on a flat commute are not, whatever the load.

What makes the difference in practice: select a lower gear on long climbs and descents so the converter locks and the engine holds the car, rather than letting the transmission hunt and slip. Do not use the highest gear at low speed under load — labouring in top is exactly the condition that keeps the converter unlocked and stirring.

If a vehicle tows regularly and runs hot doing it, the answer is usually an auxiliary cooler, which is a modest cost against a transmission.