Upshift Control and Torque Converter Clutch (TCC) Apply

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 varying current to the appropriate PC solenoids to control oncoming and offgoing clutch pressures.

Perform the following steps:

1. Monitor the following scan tool parameters:
   • Calc. Throttle Position
   • Vehicle Speed
   • Engine Speed
   • Transmission ISS
   • Transmission OSS
   • Commanded Gear
   • TCC PC Sol. Pressure Cmd.
   • TCC Pressure Actual
   • TCC Slip Speed
   • 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
2. Place the gear selector in the DRIVE position.
3. Accelerate the vehicle using a steady throttle position of 15 or 20 percent. Hold the throttle steady.
4. 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 TCC feel may not be noticeable. Look for 100-300 RPM engine speed change.
5. Note any harsh, soft or delayed shifts or slipping. Note any noise or vibration.
6. The TCC feel may not be noticeable. In many applications the TCC will apply after the 1-2 shift and TCC events will not be easily detected using engine speed.
   NOTE: This transmission is equipped with an electronically controlled capacity clutch (ECCC), which does not allow the clutch to fully lock to the torque converter cover. The clutch maintains a small amount of slippage, approximately 20 RPM, in 2nd, 3rd, 4th, 5th, and 6th gears, depending on the vehicle application. ECCC was developed to reduce the possibility of noise, vibration or chuggle caused by TCC apply. Full lockup is available at highway speeds on some applications.
7. Monitor TCC PC solenoid current while driving and make sure the current rises when the TCC is commanded to apply.
   • 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 .