1. Connect a scan tool.
2. Start the engine.
3. Depress the brake pedal.

Important: The gear selections should be immediate and not harsh.

4. Move the gear selector from:

•	Park to Reverse

•	Reverse to Neutral

•	Neutral to D

5. Perform the road test.

•	Perform this test when traffic and road conditions permit.

•	Observe all of the traffic safety regulations.

•	During the road test, note the transmission performance during the following operating conditions:

-	Part Throttle Detent Downshift

-	Full Throttle Detent Downshift

-	Manual Downshifts

-	Coasting Downshifts

-	Manual Gear Range Selection

-	Set the Cruise Control. The scan tool should indicate Active with the Cruise activates and Inactive with the Cruise deactivates.

Use a scan tool in order to see if any transmission malfunction codes have been set. If so, perform the transmission functional test. After repairing the vehicle, perform the road test and verify that no codes have been set again.

If no codes have been set and the condition remains, refer to the Diagnosis Charts contained in this section. If the condition is suspect to originate in the torque converter, refer to Torque Converter Clutch (TCC) Diagnosis later in this section.

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 hold 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.

At vehicle speeds of 64 to 88 km/h (40 to 55 mph) in 4th gear, quickly increase the throttle angle.

Verify the following conditions:

At vehicle speeds of 64 to 88 km/h (40 to 55 mph) in 4th gear, quickly increase throttle angle to its maximum position.

Verify the following conditions:

The shift solenoids do not control the initial downshift during the 4-3 and the 3-2 manual downshifts. All manual downshifts are hydraulic except the 2-1. The solenoid states will change during, or shortly after you select a manual downshift.

1. At vehicle speeds of 64 to 88 km/h (40 to 55 mph) in 4th gear, release the accelerator pedal while moving the gear selector to D3. Observe the following conditions:

•	The TCC releases.

•	The transmission downshifts to 3rd gear immediately.

•	The engine slows the vehicle down.

2. Move the gear selector back to D4 and accelerate to 64 to 72 km/h (40 to 45 mph). Release the accelerator while moving the gear selector to D2 and observe the following conditions:

•	The TCC releases.

•	The transmission downshifts to the 2nd gear immediately.

•	The engine slows the vehicle down.

3. Move the gear selector back to D4 and accelerate to 48 km/h (30 mph). Release the accelerator pedal while moving the gear selector to D1 and observe the following conditions:

•	The TCC releases.

•	The transmission downshifts to 1st gear immediately.

•	The engine slows the vehicle down.

1. With the gear selector in D4, accelerate to the 4th gear with the TCC applied.
2. Release the accelerator pedal and lightly apply the brakes. Observe the following conditions:

•	The TCC releases.

•	The downshifts occur at speeds shown on the shift speed chart.

The shift solenoids control the upshifts in the manual gear ranges.

Perform the following tests by accelerating at 10-15 degrees TP Sensor.

Manual Third (D3)

With the vehicle stopped, move the gear selector to D3 and accelerate in order to observe the following conditions:

Manual Second (D2)

Manual First (D1)

With the vehicle stopped, move the gear selector to D1. Accelerate to 32 km/h (20 mph) and observe the following conditions:

Reverse (R)

With the vehicle stopped, move the gear selector to R. Slowly accelerate and observe the 1-2 and 2-3 Shift Solenoids are on.

Use a scan tool in order to see if any ECM or TCM DTCs have been set. If any DTCs are set, perform the Powertrain OBD System Check and follow the diagnostic procedure to which you are directed. After repairing the vehicle, perform the hoist test and verify that the code has not set again.

You may want to review the Diagnosis, Electronic Control System in this section in order to become familiar with the transmission conditions that are caused by transmission electrical malfunctions.

If no trouble codes have been set and the condition is suspected to be hydraulic, take the vehicle on a road test.