Isuzu KB P190. Manual — part 994

7A2-10 TRANSMISSION CONTROL SYSTEM (AW30–40LE)

CHECK ITEM

PIN No.

VALUE

NOTE

Shift Solenoid B (S2)

C-94: 15–1

P

0V

Engine run.

R

0V

Engine run. (Without the
Reverse position lock out)

N 0V

Engine

run.

D–1 0V

D–2 VIGN

D–3 VIGN

D–4 0V

Lock-up Solenoid

C-94: 5–1

“ON”

VIGN

(ex.) It is “ON” when the
vehicle speed is more than
65km/h.

“OFF” 0V

Check Trans Lamp

C-95: 3–C-94: 1

“ON”

0V

Key “ON”

(The lamp is “ON” for 3
second after key “ON”)

“OFF” VIGN

AT Oil Temperature Lamp

C-95: 11–C-94: 1

“ON”

0V

Key “ON”

(The lamp is “ON” for 3
second after key “ON”)

“OFF” VIGN

Power Lamp

C-95: 2–C-94: 1

“ON”

0V

Key “ON”

(The lamp is “ON” when the
Power switch is “ON”)

“OFF” VIGN

3rd Start Lamp

C-95: 10–C-94: 1

“ON”

0V

Key “ON”

(The lamp is “ON” when the
3rd Start switch is “ON”)

“OFF” VIGN

AT Oil Temp Sensor
Resistance

C-94: 11–C-94: 12

20

°C/68°F

12k

Ω

Key “OFF”

50

°C/122°F 1.5k

Ω

155

°C/311°F 293

Ω

Pressure Control Solenoid
Resistance

C-94: 11–C-942

About

4–7

Ω

(20

°C/68°F)

Key “OFF”

Speed Sensor Resistance

C-95: 5–C-95: 14

About 560

Ω

–

120

Ω

(20

°C/68°F)

Key “OFF”

Input Revolution Sensor
Resistance

C-95: 6–C-95: 16

About 560

Ω

–

120

Ω

(20

°C/68°F)

Key “OFF”

Lock-up Solenoid
Resistance

C-94: 5–C-94: 1

About 10

Ω

–

15

Ω

(20

°C/68°F)

Key “OFF”

Shift Solenoid A (S1)
Resistance

C-94: 16–C-94: 1

About 10

Ω

–

15

Ω

(20

°C/68°F)

Key “OFF”

Shift Solenoid B (S2)
Resistance

C-94: 15–C-94: 1

About 10

Ω

–

15

Ω

(20

°C/68°F)

Key “OFF”

TRANSMISSION CONTROL SYSTEM (AW30–40LE) 7A2-11

Control System Diagram

RTW77AXF000301

7A2-12 TRANSMISSION CONTROL SYSTEM (AW30–40LE)

Control and Functions

Item Description

Shift and lock-up control

Shift and lock-up points can be controlled in accordance with output of S1, S2, and
SL solenoids based on "Shift-map" made up of vehicle speed and the opening.

Overdrive off cut control

When the select lever is operated from D to 3, if the vehicle speed is more than
142km/h (89mph), TCM enables to remain overdrive in order to prevent over rev.

Lock-up cut control

Lock-up is inhibited with following condition in order to improve the shift feeling.

• 1st

gear

• Idling
• Operating brake switch
• L

position

• During shift change

Driveng mode select control

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

driving condition.

1) Normal mode

2) Power mode

3) 3rd start mode

4) HOT mode

5) L4 mode

6) Up slope1 mode

7) Up slope2 mode

8) Down slope mode

9) Auto cruise mode

10) Warm up mode

• The priority of driving mode

Normal < Power < Up slope1 < Up slope2 < Down slope < L4 < Warm up < Auto
cruise < 3rd start < HOT

Oil temperature compensation
control

If the ATF temperature exceeds 130

°C (266°F), the TCM selects the HOT mode

shift pattern for lock-up, thus preventing the oil temperature from rising. (The HOT
mode is released, if the ATF temperature is less than 115

°C /239°F.)

3rd start mode control

By selecting 3rd start mode, the vehicle starting can be controls smoothly on low
frictional road like a snowy or muddy.

1. Enable

condition

a) The gear select position is "D" only.

b) Vehicle speed is less than 11km/h (7mph).

c) Transmission oil temperature is less than 120

°C (248°F).

d) Accelerator opening is less than 8%.

e) Except 3rd start mode.

2. Disable condition

a) Turning off the 3rd start mode switch

b) Shifting select position to "3", "2", or "L"(3rd start mode is not canceled by

selecting "N", "R", or "P")

c) Ignition key is turned off.

d) Vehicle speed is more than 35km/h (22mph).

L4 mode control

The TCM detects whether the transfer is engaged in high or low based on L4 switch
signal, and selects the "Shift-map".

TRANSMISSION CONTROL SYSTEM (AW30–40LE) 7A2-13

Item Description

Reverse lock out control

If the select lever is moved to "R" position during forward driving, the TCM prohibits
reverse driving by turn off the S1 and turn on the S2 for prevention of danger and
protection of the automatic transmission.

1. Enable condition

a) Vehicle speed is more than 11km/h (7mph).

2. Disable condition

a) Vehicle speed is less than 9km/h (6mph).

b) When except "R" position is detected.

Auto cruise mode control

If the auto cruise control can’t keep the setting speed like a uphill driving, the TCM
selects the auto cruise mode shift pattern for downshifting, thus keeping the vehicle
speed.

Warm-up

mode

control

TCM selects the warm-up mode shift pattern in engine cold condition for
improvement of drivability and facilitation of warm-up.

Squat control

When the TCM detects N→D garage shift, the TCM controls 1-3-1 shift by setting
timer, in order to improve the shift feel at N→D.

Coast down control

The TCM switches to the coast down control at the coasting, in order to reduce the
roughness of shifting.

Uphill control

When the TCM detected uphill, the TCM automatically switches to the uphill mode
in two-stage in proportion to inclination pitch to prevent the busy shifting and to
obtain an enough torque.

Downhill control

When the TCM detected downhill, the TCM automatically switches to the downhill
mode, and shifts to the 3rd or keeps in the 3rd in order to prevent the vehicle
acceleration. Then, the brake load is reduced by a moderate engine brake and fuel
consumption is improved by the fuel cut.

Line pressure control

The TCM controls the impressed current of the pressure control solenoid based on
the throttle opening, and regulates suitable throttle pressure.

Engine truque management
control

The TCM controls engine torque for improvement of shift quality or durability under
the following conditions.

• Upshift and downshift
• Garageshift

Indicate driving mode function The TCM indicates the following driving mode on instrument panel.

• Power mode
• 3rd start mode

Indicate oil temperature
warning function

If the transmission oil temperature sensor senses that transmission oil temperature
is greater than 146

°C (295°F), the TCM turns on ATF warning lamp. (The warning

lamp is turned off, if oil temperature is less than 126

°C/259°F.)

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.

• The "CHECK TRANS" light flashes to alert the driver, and the transmission

must be manually shifted as follows.

Select lever position

Gear position

D 4

(Fourth)

3 4

(Fourth)

2 3

(Third)

L 3

(Third)

R Reverse

Shift are firmer to prevent clutch slip and consequent wear. The fault should be
corrected as soon as possible.