Problem Symptom Confirmation (Road Test)
PROBLEM SYMPTOM CONFIRMATIONTaking into consideration the results of the customer problem analysis, try to reproduce the symptoms of the trouble, If the problem is that the transmission does not up-shift, does not down-shift, or the shift point is too high or too low, conduct the following road test the automatic shift schedule and simulate the problem symptoms.
ROAD TEST
NOTICE:
- Perform the test at normal Automatic Transmission Fluid (ATF) operating temperature (50-80°C or 122-176°F).
1. D POSITION TEST (NORM AND PWR PATTERN)
Shift into the D position and keep the accelerator pedal constant at the wide open throttle valve opening position, and check the following points:
a. Check up-shift operation
Check that 1-2, 2-3 and 3-O/D up-shift takes place, at the shift point shown in the automatic shift schedule.
Conduct the test for both Normal and Power patterns.
HINT: O/D Gear Up-shift and Lock-up Prohibition Control
1) When the following two conditions occur at the same time, the Engine Control Module (ECM) prohibits O/D gear up-shift and lock-up.
- The engine coolant temperature is 60°C (140°F) or less.
- The vehicle speed is 63 km/h (39 mph) or less. However, if the engine coolant temperature. is below 60°C (140°F) but the vehicle speed exceeds 63 km/h (39 mph), O/D gear and lock-up prohibition is cancelled. Cancellation continues until the IG 5W is turned OFF.
2) If there is a 10 km/h (6 mph) difference between the set cruise control speed and vehicle speed.
3rd Gear Up-shift Prohibition Control
When the following two conditions occur at the same time, the ECM prohibits up-shift to 3rd gear.
- The engine coolant temperature. is 35°C (95°F) or less.
- The vehicle speed is 40 km/h (25 mph) or less. However, if the engine coolant temperature. is below 35°C (95°F) but the vehicle speed exceeds 40 km/h (25 mph), 3rd gear prohibition is cancelled.
Cancellation continues until the IG 5W is turned OFF.
b. Check for shift shock and slip
Check for shock and slip at the 1-2, 2-3 and 3-O/D up-shifts.
c. Check for abnormal noise and vibration
Run at the D range lock-up or O/D gear and check for abnormal noise and vibration.
HINT: The check for the cause of abnormal noise and vibration must be perform very thoroughly as it could also be due to loss of balance in the propeller shaft, differential, torque converter clutch, etc.
d. Check kickdown operation
While running in the D position, 2nd, 3rd and O/D gears, check to see that the possible kickdown vehicle speed limits for 2 -> 1, 3 -> 2 and O/D 3 kickdowns conform to those indicated on the automatic shift schedule.
e. Check abnormal shock and slip at kickdown.
f. Check the lockup mechanism.
- Drive in D position, O/D gear, at a steady speed (lock-up ON) of about 58 km/h (36 mph).
- Lightly depress the accelerator pedal and check that the engine rpm does not change abruptly.
If there is a big jump in engine rpm, there is no lock-up.
2. 2 POSITION TEST
Shift into the 2 position and, while driving with the accelerator pedal held constantly at the wide open throttle valve opening position, push in one of the pattern selectors and check on the following points:
a. Check up-shift operation
Check to see that the 1 -> 2 up-shift takes place and that the shift point conforms to the automatic shift schedule.
HINT: There is no O/D up-shift and lock-up in the 2 position.
b. Check engine braking
While running in the 2 position and 2nd gear, release the accelerator pedal and check the engine braking effect.
c. Check for abnormal noise at acceleration and deceleration, and for shock at up-shift and down-shift.
3. L POSITION TEST
Shift into the L position and while driving with the accelerator pedal held constantly at the wide open throttle valve opening position, push in one of the pattern selectors and check the following points:
a. Check no up-shift
While running in the L position, check that there is no up-shift to 2nd gear.
b. Check engine braking
While running in the L position, release the accelerator pedal and check the engine braking effect.
c. Check for abnormal noise during acceleration and deceleration.
4. R POSITION TEST
Shift into the R position and while starting at wide open throttle, check for slipping.
5. P POSITION TEST
Stop the vehicle on a gradient (more than 5°) and after shifting into the P position, release the parking brake. Then check to see that the parking lock pawl holds the vehicle in place.
AUTOMATIC SHIFT SCHEDULE (SHIFT POINT)
AUTOMATIC SHIFT SCHEDULE (LOCK-UP POINT)
HINTS:
- There is no lock-up in the 2 and L positions.
- In the following cases, the lock-up will be released regardless of the lock-up pattern.
a) When the throttle valve is completely closed.
b) When the brake light switch is ON.
- Shift-up to 3rd will not occur when the engine coolant temperature is below 35°C (95°F) and the vehicle speed is below 40 km/h (25 mph).
- Shift-up to O/D will not occur when the engine coolant temp. is below 60°C (140°F) and the vehicle speed is below 63 km/h (39 mph).
- During cruise control operation, the shift pattern is fixed in NORM. And when the vehicle speed drops to 10 km/h (6 mph) or more below the cruise control set vehicle speed, shift down from O/D to 3rd occurs.
- The kick-down foot switch turns ON when the accelerator pedal is depressed further with the throttle valve already fully open.