Upshift Control

The TCM calculates the upshift points based primarily on 2 inputs: throttle position and vehicle speed. When the TCM determines that conditions are met for a shift to occur, the TCM commands the shift by closing or opening the ground circuit for the appropriate solenoid.

Perform the following steps:

1. Choose a throttle position of 12.5 percent or 25 percent. All throttle positions shown should be tested to cover the normal driving range.
2. Monitor the following scan tool parameters:
   • Calc. Throttle Position
   • Vehicle Speed
   • Engine Speed
   • Transmission OSS
   • Commanded Gear
   • TFP Switch 1
   • TFP Switch 3
   • TFP Switch 4
   • TFP Switch 5
   • PC Sol. 2 Pressure Cmd.
   • PC Sol. 3 Pressure Cmd.
   • PC Sol. 4 Pressure Cmd.
   • PC Sol. 5 Pressure Cmd.
   • Shift Solenoid 1 and 2
3. Place the gear selector in the DRIVE position.
4. Accelerate the vehicle using the chosen throttle position. Hold the throttle steady.
5. As the transmission upshifts, there should be a noticeable shift feel or engine speed change within 1 to 2 seconds of the commanded gear change. The feel may not be noticeable. Look for 100-300 RPM engine speed change.
6. Shift speeds may vary slightly due to TFT or other operating variables, including hydraulic delays in responding to electronic controls.
   • Note any harsh, soft or delayed shifts or slipping.
   • Note any noise or vibration.