Upshift Control and Torque Converter Clutch (TCC) Apply

The transmission control module (TCM) calculates the upshift points based primarily on two inputs: throttle angle 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. Refer to Shift Speed table in this section and choose a throttle position of 10 percent, 25 percent or 50 percent. All throttle angles shown should be tested to cover the normal driving range.
2. Monitor the following scan tool parameters:
   • Throttle angle
   • Vehicle speed
   • Engine speed
   • Commanded gear
   • Slip speed
   • Solenoid states
3. Place the gear selector in the OVERDRIVE position.
4. Accelerate the vehicle using the chosen throttle angle. Hold the throttle steady.
5. As the transmission upshifts, note the vehicle speed when the shift occurs for each gear change. There should be a noticeable shift feel or engine speed change within 1 to 2 seconds of the commanded gear change.
6. Compare the shift speeds to the Shift Speed table. Refer to Shift Speed . Shift speeds may vary slightly due to transmission fluid temperature or hydraulic delays in responding to electronic controls.
   • Note any harsh, soft or delayed shifts or slipping.
   • Note any noise or vibration.
7. Repeat steps 1 through 6 to complete all throttle angles.
IMPORTANT: The TCC will not engage until the engine is in closed loop operation and the vehicle speed is as shown in the Shift Speed table. Refer to Shift Speed . The vehicle must be in a near-cruise condition, not accelerating or coasting, and on a level road surface.
8. Check for TCC apply in THIRD and FOURTH gear.
   • Note the TCC apply point. When the TCC applies there should be a noticeable drop in engine speed and a drop in slip speed to below 100 RPM. If the TCC apply can not be detected:
     • Check for DTCs
     • Refer to Torque Converter Diagnosis .
   • Refer to Shift Speed table for the correct apply speeds.
   • Lightly tap and release the brake pedal. The TCC will release on most applications.