Transmission Adaptive Functions
Transmission Adaptive Functions
The AF33-5 uses a line pressure control system which has the ability to adapt the system line pressure in order to compensate for normal wear of clutch fiber plates, seals, springs, etc. The adapt feature is similar in function to fuel control (integrator/block learn).
The AF33-5 transmission uses the adapt function for garage shifts, upshifts, and TCC application. The TCM monitors the input shaft speed in order to determine if the shift is occurring too fast or too slow and adjusts the pressure control solenoid in order to maintain the correct shift feel.
Description and Operation
Transmission Oil Life Monitor
Transmission fluid life is determined by monitoring transmission fluid temperature over a period of time. The transmission control module (TCM) calculates transmission fluid life based on a set of temperature ranges stored in TCM memory. A counter increments as the vehicle is driven. The rate at which the counter increments, depends on the temperature range in which the transmission is currently operating. The higher the temperature range, the faster the counter increments. As the counts increment, the TCM will begin to decrease the fluid life percentage from 100, high fluid life, to 0, low fluid life. When the transmission fluid needs to be changed a DTC P1868 will set and turn on the service vehicle soon (SVS) light. The fluid life percentage can be reset with the scan tool.
Description and Operation
Transmission Indicators and Messages
Transmission Over Temperature
Transmission Over Temperature:
The engine coolant and transmission fluid in the AF33-5 shares the temperature lamp telltale. The Engine Coolant telltale lamp in the temperature gauge flashes when the transmission temperature reaches 131°C (269°F).
Service Vehicle Soon Light
Service Vehicle Soon Light:
The Service Vehicle Soon (SVS) lamp will come on when certain transmission diagnostic DTC's are present. The SVS lamp will be cleared when the DTC is cleared and the fault is removed.