Transmission Operating Mode Test

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) can controls 4L30-E operation in three modes: Power mode, Normal mode, and Winter mode. The driver determines the transmission operating mode through the Power/Normal mode switch and the Winter mode switch.
The Power mode provides better part-throttle acceleration by providing earlier part-throttle upshifts.
In Winter mode, the transmission starts in third gear to reduce tire slippage on ice and snow. When the driver selects Winter mode, the TCM overrides the Power or Normal mode. The TCM will enter Winter mode only when all of the following conditions are met:
- Selector lever in D range.
- Vehicle speed 7 mph (11 km/h) or less.
- Transmission oil temperature 120°C (248°F) or less.
- Throttle opening 8% or less.
- Kick-down switch is off.
Winter mode will be canceled if any of the following conditions are met:
- Driver depresses Winter mode switch again.
- Driver moves selector lever to 3,2 or L (TCM will stay in Winter mode if lever is moved from D to N or R or P).
- Ignition switch is turned off.
- Vehicle speed is 21 mph (34 km/h) or more for longer than one second.
- Transmission oil temperature is greater than 140°C (284°F).
- Kickdown switch is "ON" for more than 3 seconds.
When Winter mode is canceled, the TCM returns the transmission to Normal mode.