Road Test

Road Test

^ Perform the road test using a scan tool.
^ This test should be performed when traffic and road conditions permit.
^ Observe all traffic regulations.

The TCM calculates upshift points based primarily on two 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 "wide open throttle" 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 introduction manual to see if this test is available.

Upshift Procedure
With gear selector in drive (D)

1. Look at the shift speed chart contained and choose a percent throttle angle of 10 or 25%.
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.

Note when TCC applies. This should occur in fourth gear. If the apply is not noticed by an RPM drop, refer to the "Lock-up Clutch Diagnosis" information contained. The lock up clutch should not apply unless the transaxle has reached a minimum operating temperature of 8 °C (46 °F) trans temp. and engine coolant temp. of 50 °C (122 °F).

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

Part Throttle Detent Downshift
At vehicle steeds of 55 - 65 km/h (34 - 40 mph) in Fourth gear, quickly increase throttle angle to greater than 50%. Verify that:
^ TCC apply.
^ Transaxle downshift to 3rd gear.
^ Solenoid 1 turns ON to OFF.
^ Solenoid 2 turns OFF.

Full Throttle Detent Downshift
At vehicle speeds of 55 - 65 km/h (34 - 40 mph) in Fourth gear, quickly increase throttle angle to its maximum position (100%) Verify that:
^ TCC release.
^ Transaxle downshift to Second gear immediately.
^ Solenoid 1 turns ON to OFF.
^ Solenoid 2 turns OFF.

Manual Downshifts
1. At vehicle speeds of 60 km/h (40 mph) in Fourth gear, release accelerator pedal while moving gear selector to Manual Third (3). Observe that:
^ Transaxle downshift to Third gear immediately.
^ Engine slows vehicle down.

2. Move 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 First (1) and observe that:
^ Transaxle downshift to second gear immediately.
^ Engine slows vehicle down.

Coasting Downshifts
1. With the gear selector in Overdrive (D), accelerate to Fourth gear with TCC applied.
2. Release the accelerator pedal and lightly apply the brakes, and observe that:
^ TCC release.
^ Down shifts occur at speeds shown ON the shift speed chart.

Manual Gear Range Selection
Upshifts in the manual gear ranges are controlled by the shift solenoids. Perform the following tests by accelerating at 25% TP sensor increments.

Manual Third (3)
^ With vehicle stopped, move the gear selector to Manual third (3) and accelerate to observe:
^ 1 - 2 shift.
^ 2 - 3 shift.

Manual Second (2)
^ With vehicle stopped, move the gear selector to Manual second (2) and accelerate to observe:
^ 1 - 2 shift.

^ Accelerate to 40 km/h (25 mph) and observe:
^ 2 - 3 shift does not occur.
^ TCC does not apply.

Manual First (1)
^ With vehicle stopped, move gear selector to Manual First (1). Accelerate to 30 km/h (19 mph) and observe:
^ No upshifts occur.

Reverse (R)
^ With vehicle stopped, move gear selector to R (Reverse) and observe:
^ Solenoid 1 is OFF.
^ Solenoid 2 is OFF.

Use a scan tool to see if any transaxle trouble codes have been set. Refer to DTC Identification 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 transaxle 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. You also have to perform a snapshot test which can help catch an intermittent condition that dose not occur long enough to set a code.

You may want to read "Electronic Component Diagnosis" to become familiar with transaxle conditions caused by transaxle electrical malfunction.

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