For 1990-2009 cars

• | Perform the road test using a scan tool.

• | Perform this test when the traffic and the road conditions permit. Observe all safety regulations.

1. Start the engine.
2. Depress the brake pedal.

Important: Gear selections should be immediate and not harsh.

3. Move the gear selector as follows:

3.1. | Park to Reverse.

3.2. | Reverse to Neutral.

3.3. | Neutral to D4.

4. Perform the same procedure as instructed previously in the road test:

• | Upshifts and TCC apply.

• | The part throttle detent downshift

• | The full throttle detent downshift

• | Manual downshifts

• | Coasting downshifts

• | Manual gear range selection

Use the scan tool in order to see if any transmission malfunction codes have been set. If so, perform the transmission 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 Tables contained in this section. If the condition is suspected to originate in the torque converter, refer to Torque Converter Clutch (TCC) Diagnosis .

### Upshift Control and TCC Apply

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

The shift speed charts reference the THROTTLE ANGLE instead of MIN 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 are programmed to record shift point information. Check the instruction manual in order to see if this test is available.

With the gear selection in D4, do the following:

1. Look at the shift speed chart contained in this section and choose a throttle angle of 15 or 20 percent.
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: Shift speeds may vary due to the slight hydraulic delays responding to electronic controls. A change from the original equipment tire size also affects the shift speeds.

Note when the TCC applies. This should occur in third or fourth gear. If the apply is not noticed by an RPM drop, refer to the Preliminary Torque Converter Clutch Diagnosis. The TCC should not apply unless the transmission has reached a minimum operating temperature of 18°C (64°F) TRAN TEMP and an engine coolant temperature of 60°C (140°F).
4. As the transmission upshifts, note the shift speed and the commanded gear changes for the following:

• | 2nd gear

• | 3rd gear

• | 4th gear

5. Repeat steps 1-4, using several different throttle angles.

### Full Throttle Detent Downshift

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

Verify that the following conditions are met:

• | The TCC releases.

• | The transmission downshifts to 2rd gear immediately.

• | The 1-2 shift solenoid turns off. The 2-3 shift solenoid is on.

### Part Throttle Detent Downshift

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

Verify that the following conditions are met:

• | The TCC releases.

• | The transmission downshifts to 3rd gear immediately.

• | The 1-2 shift solenoid turns off.

### Coasting Downshifts

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

• | The TCC releases

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

### Manual Downshifts

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 a manual downshift is selected.

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 D3. Observe the following:

• | The TCC releases.

• | The transmission downshifts to 3rd gear immediately.

• | The engine slows down the vehicle.

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

• | The TCC releases.

• | The transmission downshifts to the 2nd gear immediately.

• | The engine slows down the vehicle.

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 down the vehicle.

### Manual Gear Range Selection

Upshifts in the manual gear ranges are controlled by the shift solenoids.

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:

• | 1-2 shift

• | 2-3 shift

#### Manual Second (D2)

1. With the vehicle stopped, move the gear selector to the D2 position and accelerate in order to observe if the transmission starts and remains in second gear.
2. Accelerate to 40 km/h (35 mph) and observe the following:

• | The 2-3 shift does not occur.

• | The TCC does not apply.

#### Manual First (D1)

1. With the vehicle stopped, move the gear selector to D1.
2. Accelerate to 32 km/h (20 mph).
3. Observe the following conditions:

• | No upshifts occur.

• | The TCC does not apply.

• | You can upshift out of first at the fuel cut-off.

#### Reverse

With the engine stopped, move the gear selector to R and slowly accelerate in order to observe that the 1-2 and 2-3 shift solenoids are ON.

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

If the transmission is not performing well and no trouble codes have been 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 doesn't occur long enough to set a code.

You may want to read Electronic Component Diagnosis in this section in order to become familiar with the transmission conditions 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.