The TCM compares current driving conditions with those stored in its memory based on input from the engine speed sensor, throttle position sensor, engine coolant temperature sensor, brake application signal, and shift lever position signal to control shifting during ascent, descent, or deceleration..
Load increasing control
When the TCM detects that the vehicle is going uphill in the [D4] position, the system expands the operating area of 3rd gear to prevent the transmission from frequently shifting between 3rd and 4th gears, so the vehicle can drive smoothly and have more power when needed..
Note:
- The shift diagram between 3rd and 4th gears is stored in the TCM, allowing "Flexible logic" TCM automatically selects the most suitable gear according to the magnitude of the slope.
- "Flexible logic"is a form of artificial intelligence that allows computers to respond to changing conditions in the same way that the human mind does.
Load reduction control
When the TCM detects that the vehicle is going downhill in the [D4] position, shifting from 3rd to 4th when the throttle is closed becomes faster than on a flat road due to the widening of the 3rd gear range.
This, combined with engine braking when decelerating, helps achieve a smooth ride when descending the vehicle.
There are two load increasing modes with different 3rd gear control areas, in accordance with the grade value stored in the TCM.
When the vehicle is in 4th gear and you brake down a gentle hill, or when you apply the brakes on a steep hill, the transmission will downshift to 3rd gear. When you increase speed, the transmission will return back to 4th gear.
Deceleration control
When the vehicle is cornering and requires deceleration and then acceleration, the TCM sets deceleration control data to reduce the number of transmission shifts. When the vehicle decelerates from 48 km/h, the TCM shifts the transmission from 4th to 2nd gear earlier than under normal conditions to cope with the increasing acceleration.
Electrical diagram
Automatic transmission electronic control unit connector (TSM)