Road Test

U241E AUTOMATIC TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: ROAD TEST

1. PROBLEM SYMPTOM CONFIRMATION

(a) Based on the result of the customer problem analysis, try to reproduce the symptoms. If the problem is that the transaxle does not shift up or down or the shift point is too high or too low, conduct the following road test referring to the automatic shift schedule and simulate the problem symptoms.

2. ROAD TEST

NOTICE:
Perform the test with the ATF (Automatic Transmission Fluid) at a temperature of 50 to 80°C (122 to 176°F) in normal operation.

(a) D position test:

Move the shift lever to D, fully depress the accelerator pedal, and check the following points.

(1) Check up-shift operation.

Check that 1 -> 2, 2 -> 3 and 3 -> 4th up-shifts take place, and that the shift points conform to the automatic shift schedule Pressure, Vacuum and Temperature Specifications.

HINT
4th Gear Up-shift Prohibition Control

* Engine coolant temperature is 55°C (131°F) or less and vehicle speed is at 70 km/h (43 mph) or less.
* ATF temperature is 5°C (41°F) or less.
4th Gear Lock-up Prohibition Control

* Brake pedal is depressed.
* Accelerator pedal is released.
* Engine coolant temperature is 60°C (140°F) or less.

(2) Check for shift shock and slip.

Check for shock and slip at the 1 -> 2, 2 -> 3 and 3 -> 4th up-shifts.

(3) Check for abnormal noise and vibration.

Check for abnormal noise and vibration when up-shifting from 1 -> 2, 2 -> 3 and 3 -> 4th while driving with the shift lever in D, and also check while driving in the lock-up condition.

HINT
Checking for the cause of abnormal noise and vibration must be done thoroughly as it could also be due to loss of balance in the differential, torque converter clutch, etc.

(4) Check kick-down operation.

Check vehicle speeds when the 2 -> 1, 3 -> 2 and 4 -> 3 kick-downs take place while driving with the shift lever in D. Confirm that each speed is within the applicable vehicle speed range indicated in the automatic shift schedule Pressure, Vacuum and Temperature Specifications.

(5) Check for abnormal shock and slip at kick-down.

(6) Check the lock-up mechanism.

* Drive with the shift lever in D (4th gear), at a steady speed (lock-up ON).

* Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.

HINT
* There is no lock-up function in the 1st and 2nd gears.
* If there is a big jump in engine speed, there is no lock-up.

(b) S position test:

Move the shift lever to S, depress the accelerator pedal, and check the following points.

(1) Check shift operation.

* While driving with the shift lever in D and in 4th gear, move the shift lever to S and back to D. Check that the 4-> 3 down-shift and 3-> 4 up-shift can be performed.

* With the shift lever in S (while the vehicle is stopped), shift into the "+" position to check that the shift indicator on the combination meter changes as follows: 1 -> 2, 2 -> 3 and 3 -> 4.

* While driving with the S3 range selected and in 3rd gear (at a vehicle speed of approximately 30 to 40 km/h (19 to 25 mph)), shift into the "-" position and check if the 2nd gear down-shift occurs and the engine brake performs properly.

* While driving with the S2 range selected and in 2nd gear (at a vehicle speed of approximately 20 to 30 km/h (12 to 19 mph)), shift into the "-" position and check if the 1st gear down-shift occurs and the engine brake performs properly.

HINT
Manual shift (S position) is prohibited under either of the following conditions:

* Down-shifting may cause engine overrun.
* The driver continuously down-shifts. (Down-shifting to 1st gear may not be performed.)

(c) R position test:

Move the shift lever to R, lightly depress the accelerator pedal, and check that the vehicle moves backward without any abnormal noise or vibration.

CAUTION:
Before conducting this test ensure that the test area is free from people and obstructions.

(d) P position test:

Stop the vehicle on a grade (more than 5°) and after moving the shift lever to P, release the parking brake. Then, check that the parking lock pawl holds the vehicle in place.

(e) Uphill/downhill control function:

(1) Check that the gear does not up-shift to the 4th gear while the vehicle is driving uphill.

(2) Check that the gear automatically down-shifts from the 4th to 3rd gear when brake is applied while the vehicle is driving downhill.