Isuzu Trooper (1998-2002 year). Manual — part 702

AUTOMATIC TRANSMISSION (AW30-40LE)

7A–5

TRANSMISSION CONTROL MODULE (TCM)

C07RY00027

7A–6

AUTOMATIC TRANSMISSION (AW30-40LE)

CONTROL SYSTEM DIAGRAM

C07RY00071

AUTOMATIC TRANSMISSION (AW30-40LE)

7A–7

CONTROL AND FUNCTIONS

Item

Description

Shift and lock-up control

• In D range, speed change point and Lock-up point can be changed by

setting pattern selection switch to "POWER", "NORMAL" or "WINTER"
mode.

• Gear shift position in the conditions made up of transmission shift positions

(D.2.L) combined with pattern selection switch (POWER, NORMAL, and
WINTER) can be controlled in accordance with vehicle speed and the
opening of throttle valve.

Overdrive cut control

• If O/D OFF switch is set on in D range (O/D OFF lamp ON), gear shift to O/

D is not effected.

• Overdrive is released at O/D OFF switch on and high transmission oil

temperature (More than 130

°

C).

However, to prevent engine over revolution

• 4

→

3 shifting at vehicle speed is less than 118 km/h.

• 3

→

4 shifting at vehicle speed is more than 131 km/h.

Lock-up cut control

• In D range, 3rd or O/D lock-up is conducted in "POWER" or "NORMAL"

mode.

• In 2, L range, lock-up is off in the whole area.

• Lock-up timing is controlled to reduce gear shift shock using kind of gear

shift (shift up, etc.) lock-up status at the time of gear shift judgement, gear
step and throttle opening after gear shift.

• Lock-up is released at brake on or high transmission oil temperature (More

than 130

°

C).

• Lock-up is prohibited when idling is defected by throttle position sensor.

Driving mode select control

• The TCM selects a suitable driving mode from the nine kinds for the variety

driving condition.

i)Economy mode ii)Power mode iii)Winter mode iv)HOT1 mode v)HOT2
mode vi)L4 mode vii)Slope mode (Up slope 1, Up slope 2 and Down
slope mode)

• The priority of driving mode:

Economy < Power < Slope < L4 < Winter < HOT1 < HOT2

Squat control

• When the TCM detects D signal on, the TCM controls 1–3–1 shift by

setting a timer, in order to improve the shift feel at N

→

D.

Line pressure control

• The TCM output current which corresponds to throttle oil pressure to

pressure control solenoid based on throttle opening.

Indicate oil temperature warning
function

• If the transmission oil temperature sensor senses that transmission oil

temperature is greater than 146

°

C, the TCM turn on A/T OIL TEMP

warning lamp. (The warning lamp is turned off, if oil temperature is less
than 126

°

C.)

L4 mode control

• The TCM judges whether the transfer is engaged in high or low based on

the ratio rpm data from output speed sensor in the transmission and the
rpm data from speed meter sensor to select the shift map.

Up and down hill control

• The TCM judges up and down hill, and change shift pattern based on

throttle opening and acceleration.

Correct oil temperature control

• If the temperature exceeds a predetermined value, the TCM selects the

high oil temperature shift point for downshifting, thus preventing the oil
temperature from rising. (More than 130

°

C, D range)

7A–8

AUTOMATIC TRANSMISSION (AW30-40LE)

Winter mode control

• The TCM controls the vehicle start smoothly on low frictional road like

snow road by executing this control.

Activate condition:

1. Excluding "2", "L" range

2. Vehicle speed is less than 11 km/h

3. Transmission oil temperature is less than 115

°

C

4. Throttle opening is less than 8%

5. Excluding winter mode

Cancel condition:

1. When winter mode switch is pushed again

2. When either "2" or "L" is detected

3. Ignition switch "OFF"

4. Vehicle speed is more than 34 km/h for 1 second or mode continuously

5. Transmission oil temperature is more than 130

°

C

Fail-safe function

• When trouble occurs to vehicle sensor and each solenoid, TCM

automatically exerts fail-safe control not to spoil driveability.

• This control is exerted when sensor or actuator is in trouble, while TCM

works normally.

Diagnosis function

• If there is an abnormality in vehicle sensors, each solenoid (S1-S3, STH),

or throttle position sensor, "CHECK TRANS" lamp is actuated to warn the
drive. But when the abnormality items have been restored to normal, the
light does not blink.

• Faulty parts are memorized in TCM. If self-diagnosis start signal is

inputted, "CHECK TRANS" lamp is blinked and results of diagnosis are
indicated. A history of faults remains recorded even when IGN switch is off.

TECH 2

• Output of control data in the TCM

• Actuator (Solenoid) operation check

• Erasure of trouble code