Upshift Control and Torque Converter Clutch Apply

The TCM calculates the upshift points based primarily on two inputs: The Throttle Angle and the Vehicle Speed. When the TCM says a shift should occur, the shift solenoids receive an electrical signal which in turn moves the valves in order to perform the upshift.

The shift speed charts reference the Throttle Angle instead of minimum throttle or WOT in order to make the shift speed measurement more uniform and accurate. Use a scan tool in order to monitor the Throttle Angle. Some scan tools have been programmed in order to record the shift point information. Check the instruction manual in order to see if this test is available.

With the gear selector in D4, perform the following steps:
1. Look at the shift speed chart in this section and choose a percent throttle angle of 15 or 20.
2. Set up the scan tool in order to monitor the Throttle Angle and the Vehicle Speed.
3. Accelerate to the chosen throttle angle and hole the throttle steady.

Important:
^ The shift speeds may vary due to any slight hydraulic delays in responding to the electronic controls. A change from the original equipment tire size also affects the shift speeds.
^ Note when the TCC applies. This should occur in 3rd or 4th gear. If the apply does not occur by an RPM drop, refer to the Preliminary Torque Converter Clutch Diagnosis information contained in this section.
^ The TCC should not apply unless the transmission has reached a minimum operating temperature of 18° C and the engine coolant temp of 60° C.

4. As the transmission upshifts, note the shift speed and commanded gear changes for:
- 2nd gear
- 3rd gear
- 4th gear
5. Repeat steps 1-4 by using several different throttle angles.