For 1990-2009 cars

• | Perform the road test using a Scan Tool.

• | Perform this test only when traffic and road conditions permit.

• | Observe all traffic safety regulations.

The PCM calculates upshift points based primarily on two inputs: TP ANGLE and VEHICLE SPEED. When the PCM says that a shift should occur, an electrical signal is sent to the shift solenoids. The solenoids in turn move the valves in order to perform the upshift.

The shift speed chart refers to TP ANGLE instead of Min Throttle or WOT in order to make shift speed measurement more uniform and accurate. A scan tool should be used in order to monitor TP ANGLE. Some scan tools have been programmed to record shift point information. Check the instruction manual in order to see if this test is available.

### Upshift Control and Torque Converter Clutch (TCC) Apply

With gear selector in Overdrive (D), perform the following steps:

1. Refer to Shift Speed and choose a throttle angle of either 10% or 25%.
2. Monitor TP ANGLE and VEHICLE SPEED with the scan tool.
3. Accelerate to the chosen throttle angle. Hold the throttle steady.

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

4. As the transmission upshifts, note the shift speed for each of the following gears:

• | 2nd gear

• | 3rd gear

• | 4th gear

5. The Torque Converter Clutch (TCC) should not apply unless the transmission has reached a minimum TRANS FLUID temperature of 8°C (46°F) and ECT temperature of 50°C (122°F). Note when the TCC applies. This should occur in Fourth gear. If you do not notice the apply by an RPM drop, refer to Torque Converter Clutch Evaluation and Diagnosis .
6. Repeat steps 1-5 using several different throttle angles.

### Part Throttle Detent Downshift

At vehicle speeds of 64-88 km/h (40-55 mph) in Fourth gear, quickly increase the TP ANGLE to greater than 50%. Verify the following results:

• | The TCC releases.

• | The transmission downshifts to 3rd gear immediately.

• | The 1-2 Shift Solenoid valve turns Off.

• | The 2-3 Shift Solenoid valve remains On.

### Full Throttle Detent Downshift

At vehicle speeds of 64-88 km/h (40-55 mph) in Fourth gear, quickly increase the TP ANGLE to its maximum position. Verify the following results:

• | The TCC releases.

• | The transmission downshifts to Second gear immediately.

• | The 1-2 and 2-3 Shift Solenoid valves turn Off.

### Manual Downshifts

The shift solenoid valves do not control the initial 4-3 manual downshift. The 4-3 manual downshift is hydraulic, but the 3-2 and the 2-1 downshifts are electronic. The solenoid states will change during, or shortly after, a manual 4-3 downshift is selected.

Important: A manual First-Third Gear Ratio will occur at high speeds as an upshift safety feature. Do not attempt to perform this shift.

1. At vehicle speeds of 64-88 km/h (40-55 mph) in Fourth gear, release the accelerator pedal while moving the gear selector to Manual Third (3). Observe the following results:

• | The TCC releases.

• | The transmission downshifts to Third gear immediately.

• | The engine slows the vehicle down.

2. Move the gear selector back to Overdrive (D) and accelerate to 64-72 km/h (40-45 mph). Release the accelerator while moving the gear selector to Manual Second (2) and observe the following results:

• | The TCC releases.

• | The transmission immediately downshifts to Second gear.

• | The engine slows the vehicle down.

3. Move the gear selector back to Overdrive (D) and accelerate to 64 km/h (40 mph). Release the accelerator pedal while moving the gear selector to Manual First (1) and observe the following results:

• | The TCC releases.

• | The transmission immediately downshifts to Second gear immediately.

• | The engine slows the vehicle down.

• | Below 60 km/h (37 mph), the transmission downshifts to First gear.

### Coasting Downshifts

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

• | The TCC releases.

• | Downshifts occur at speeds shown on the Shift Speed Chart. Refer to Shift Speed .

### Manual Gear Range Selection

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

Perform the following tests by accelerating at 10% TP ANGLE.

#### Manual Third (3)

With the vehicle stopped, move the gear selector to Manual Third (3) and accelerate in order to observe the following conditions:

• | The 1-2 shift

• | The 2-3 shift

#### Manual Second (2)

1. With the vehicle stopped, move the gear selector to Manual Second (2) and accelerate in order to observe the 1-2 shift.
2. Accelerate to 40 km/h (25 mph) and observe the following conditions:

• | The 2-3 shift does not occur.

• | The TCC does not apply.

#### Manual First (1)

With the vehicle stopped, move the gear selector to Manual First (1). Accelerate to 32 km/h (20 mph) and observe the following conditions:

• | No upshifts occur.

• | The TCC does not apply.

#### Reverse (R)

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

• | The 1-2 Shift Solenoid valve is ON.

• | The 2-3 Shift Solenoid valve is OFF.

Use a scan tool in order to see whether any transmission trouble codes have been set. Refer to Diagnostic Trouble Codes and repair the vehicle as directed. After repairing the vehicle, perform the hoist test and verify that the code did not set again.

If the transmission is still not performing well but no trouble codes have set, there may be an intermittent condition. Check all electrical connections for damage or a loose fit. Some scan tools have a snapshot test which can help catch an intermittent condition that does not occur long enough to set a code.

Refer to Electronic Component Description in order to become familiar with transmission conditions caused by transmission electrical malfunctions.

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