The transmission control module (TCM) calculates upshift points based primarily on 2 inputs : throttle angle and vehicle speed. When the TCM wants a shift to occur, an electrical signal is sent to the shift solenoids which in turn moves the valves to perform the upshift.

The shift speed charts reference throttle angle instead of min throttle or wot to make shift speed measurement more uniform and accurate. A scan tool should be used to monitor throttle angle. Some scan tools have been programmed to record shift point information. Check the instruction manual to see if this test is available.

With the gear selector in drive (D):

1. Look at the shift speed table and choose a percent throttle angle of 10 or 25 percent. Refer to Shift Speed .
2. Set up the scan tool to monitor throttle angle and vehicle speed.
3. Accelerate to the chosen throttle angle and hold the throttle steady.
4. As the transaxle upshifts, note the shift speed and commanded gear changes for :

•	Second gear

•	Third gear

•	Fourth gear

Important: Shift speeds may vary due to slight hydraulic delays responding to electronic controls. A change from the original equipment tire size affects shift speeds.

Note when the torque converter clutch (TCC) applies. This should occur in 4th gear. If the apply is not noticed by an RPM drop, refer to Torque Converter Diagnosis .
The lock up clutch should not apply unless the transaxle has reached a minimum operating temperature of 8°C (46°F) transmission temperature and engine coolant temperature of 50°C (122°F).
5. Repeat steps 1-4 using several different throttle angles.

At vehicle steeds of 55-65 km/h (34-40 mph) in 4th gear, quickly increase throttle angle to greater than 50 percent.

At vehicle speeds of 55-65 km/h (34-40 mph) in 4th gear, quickly increase throttle angle to its maximum position, 100 percent.

Important: A manual 1st--3rd gear ratio will occur at high speeds as an upshift safety feature. Do not attempt to perform this shift.

1. At vehicle speeds of 60 km/h (40 mph) in 4th gear, release the accelerator pedal while moving the gear selector to manual 3rd.

•	Verify that the transaxle downshifts to 3rd gear immediately.

•	Verify that the engine slows vehicle down.

2. Move the gear selector back to overdrive (D) and accelerate to 50 km/h (31 mph). Release the accelerator pedal and move the gear selector to manual 1st.

•	Verify that the transaxle downshifts to 2nd gear immediately.

•	Verify that the engine slows the vehicle down.

1. With the gear selector in Overdrive (D), accelerate to 4th gear with TCC applied.
2. Release the accelerator pedal and lightly apply the brakes.

•	Observe that the TCC releases.

•	Observe that the down shifts occur at speeds shown ON the shift speed chart.

Upshifts in the manual gear ranges are controlled by the shift solenoids. Perform the following tests by accelerating at 25 percent TP sensor increments.

Manual Third (3)

With the vehicle stopped, move the gear selector to manual 3rd (3) and accelerate to observe 1-2 shift and 2-3 shift.

Manual Second (2)

Manual First (1)

With the vehicle stopped, move the gear selector to manual 1st (1). Accelerate to 30 km/h (19 mph) and observe that no upshifts occur.

Reverse (R)