Road Test

U151F AUTOMATIC TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: ROAD TEST

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, shift 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
NOTE: Perform the test at the ATF temperature 50 to 80°C (122 to 176°F) in the normal operation.

(a) D position test:
Shift into the D position and fully depress the accelerator pedal and check the following points.
(1) Check up-shift operation.
Check that 1 -> 2, 2 -> 3, 3 -> 4 and 4 -> 5th up-shifts take place, and that the shift points conform to the automatic shift schedule Service Data.
HINT: 5th Gear Up-shift Prohibition Control
- Coolant temperature is 70°C (158°F) or less and vehicle speed is at 80 km/h (50 mph) or less.
- ATF temperature is -2°C (28°F) or less.
4th Gear Up-shift Prohibition Control
- Coolant temperature is 70°C (158°F) or less and vehicle speed is at 55 km/h (34 mph) or less.
5th and 4th Gear Lock-up Prohibition Control
- Brake pedal is depressed.
- Accelerator pedal is released.
- 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, 3 -> 4 and 4 -> 5th up-shifts.
(3) Check for abnormal noise and vibration.
Drive in the D position lock-up or 5th gear and check for abnormal noises and vibration.
HINT: The check for the cause of abnormal noise and vibration must be done very thoroughly as it could also be due to loss of balance in the differential, torque converter clutch, etc.
(4) Check kick-down operation.
Check that the possible kick-down vehicle speed limits for 2nd to 1st, 3rd to 2nd, 4th to 3rd, 5th to 4th kick-downs conform to those indicated on the automatic shift schedule while driving through all gears with the shift lever in the D position Service Data.
(5) Check abnormal shock and slip at kick-down.
(6) Check the lock-up mechanism.

- Drive in D position (5th 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 in the 1st, 2nd, and 3rd gear.
- 3rd lock-up operates while uphill control is active.
- If there is a big jump in engine speed, there is no lock-up.

(b) S position test
Shift to the S position, depress the accelerator pedal and check the following points:
(1) Check shift operation.

- While driving in the D position and 5th gear, shift into the D position and S position and back to the D position. Check that the gear change 5 -> 4 down-shift and 4 -> 5 up-shift can be performed.
- With the shift lever in the S position (with the vehicle stopped), shift into the "+" position to check that the shift position on the combination meter changes as follows : 1 -> 2, 2 -> 3, 3 -> 4 and 4 -> 5.
- While driving in the 4(S) position and 4th gear (at a vehicle speed of about 40 to 50 km/h (25 to 31 mph)), shift into the "-" position and check if the 3rd gear down-shift occurs and the engine brake performs properly.
- While driving in the 3(S) position and 3rd gear (at a vehicle speed of about 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 in the 2(S) position and 2nd gear (at a vehicle speed of about 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) prohibition control
- Down-shifting causes engine overrun.
- Down-shifting is required continuously. (Down-shifting to 1st gear may not be performed.)

(c) R position test:
Shift into the R position, 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 obstruction.

(d) P position test:
Stop the vehicle on a grade (more the 5°) and after shifting into the P position, release the parking brake. Then, check that the parking lock pawl holds the vehicle in place.
(e) Uphill/downhill control function test:
(1) Check that the gear does not up-shift to the 3rd to 4th or 4th to 5th gear while the vehicle is driving uphill.
(2) Check that the gear automatically down-shifts from the 5th to 4th or from the 4th to 3rd gear when brake is applied while the vehicle is driving downhill.