Upshift Control and Torque Converter Clutch (TCC) Apply

The transmission control module (TCM) calculates the upshift points based on the throttle angle and the engine, turbine and output speed. When the TCM determines that conditions are met for a shift to occur, the TCM commands the shift, and controls A and B solenoid current to proper control clutch pressures during the shift.

Perform the following steps:

1. 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
   • Output shaft speed
   • Commanded range
   • Slip speed
   • Solenoid states
3. Place the shift selector in DRIVE.
4. Using the chosen throttle angle, accelerate the vehicle. Hold the throttle steady.
5. As the transmission upshifts, note the vehicle speed when the shift occurs for each range change. There should be a noticeable shift feel or engine speed change within 1 to 2 seconds of the commanded range change.
6. Shift speeds may vary slightly due to transmission fluid temperature or hydraulic delays in responding to the electronic controls.
   • Note any harsh, soft or delayed shifts or slipping.
   • Note any noise or vibration.
7. Repeat steps 1-6 to complete all throttle angles.
IMPORTANT: The TCC will not engage until the engine is in closed loop operation. The vehicle must be in a near cruise condition, not accelerating or coasting, and on a level road surface.
8. Inspect for TCC apply in SECOND, THIRD, FOURTH and FIFTH range.
   • 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 inspect for DTCs. Refer to Torque Converter Diagnosis Procedure .
   • Lightly tap and release the brake pedal. The TCC will release on most applications.