First gear ’1’ Range (Automatic gearbox - JF403E)

First gear ’1’ Range

The forward clutch and over-run clutch are engaged to connect the front planetary carrier and rear internal gear. The low and reverse brake also operates to lock the front planetary carrier and rear internal gear.

First gear in ’1’ range is different to that in ’D’, ’3’ or ’2’ ranges. Engagement of the over-run clutch locks the forward one-way clutch and also engagement of the low and reverse brake instead of the low one-way clutch locks the rear internal gear.

During over-run or when a gear shift takes place from ’2’ to ’1’, a counter driving force is transmitted to the input shaft to obtain engine braking by preventing the forward one-way clutch and the low one-way clutch from free-wheeling.

Component condition:

Forward clutch - Engaged Forward one-way clutch - Operative Over-run clutch - Engaged

Low and reverse brake - Engaged

Power path:

Input shaft - Rear sun gear - Rear pinion gear - Rear planetary carrier - Output shaft

Electronic Control

Line pressure control

ECU controls line pressure according to throttle opening angle and vehicle driving condition.

Gear shift control

ECU decides correct gear for vehicle driving condition according to vehicle speed, throttle opening angle, shift range and shift pattern. Shift patterns can be changed by pressing ’Sport’ and ’Snow’ mode switches.

Lock-up control

ECU controls lock-up solenoid according to vehicle speed and shift range.

Engine brake control

ECU controls over-run clutch solenoid according to throttle opening angle, vehicle speed, shift range and shift pattern, engaging over-run clutch to provide engine braking.

Torque down control

ECU requires engine ECM to bring down engine torque temporarily during shifting.

’N’ and ’D’ select signal output control

To prevent engine idle speed from dropping below the managed idle speed, the ECU transmits a signal to the engine ECM when the selector is moved from ’N’ to ’D’, ’3’, ’2’ or ’1’ range.

Self diagnosis function

The ECU memories faults, and when self-diagnosis is initiated, the ’Sports’ mode warning light flashes a fault code.

Fail safe function

If a malfunction is detected, the ECU activates a ’back-up’ mode to minimise the effects on vehicle performance.