2004 ISUZU TF SERIES turn signal

7A1-22 CONSTRUCTION AND FUNCTION
TURBINE SENSOR

The turbine sensor is a hall element. It is installed to the front of the transmission case. The turbine
sensor converts the rotations of the reverse & high clutch drum fitted with the input shaft by spline to
pulse signal and sends the signal to TCM.

One turn of the reverse & high clutch drum generates 32-pulse signal, which is sent to the TCM.


Figure 38. Turbine Sensor

SPEED SENSOR

The speed sensor is a hall element. It is installed to the rear of the transmission case. The speed sensor
converts the rotations of the parking gear fitted with the output shaft by spline to a pulse signal which is
sent to the TCM.

One turn of the parking gear generates a 16-pulse signal to be sent to the TCM.


Figure 39. Speed Sensor Figure 40. Location of Turbine & Speed Sensor

7A1-24 CONSTRUCTION AND FUNCTION
BRAKE SWITCH

The brake switch is installed to the brake pedal. When the driver steps on the brake pedal, an electric
signal is sent to the TCM.



Brake Switch
Accelerator Pedal
Brake Pedal



TCM A3 +12V
Figure 45. Brake Switch Figure 46. Pin Assignment


MODE SELECT SWITCH

The mode select switch is installed beside the select lever. When the driver selects the PWR or 3rd, an
electric signal is sent to the respectively. It turns ON the indicator lamp in the meter.

The 3rd START mode can be used only in the D range.

Mode Select Switch
Gear Select Lever









Power 3rd Illumination
Lamp
1 (Illumination)
2 (Ground)
3 (TCM A24)
4 (No Connection)
5 (TCM A11)
6 (Ground)

21
65 4 3
Figure 47. Mode Select Switch Figure 48. Pin Assignment

7A1-26 CONSTRUCTION AND FUNCTION
CONTROL MECHANISM
CONTENT OF FUNCTION AND CONTROL
Item Description
Line pressure control TCM issues a signal according to the vehicle traveling, engine load and other conditions to
TCM and the ON/OFF type line pressure solenoid is driven to switch the line pressure to
high or low pressure.
The line pressure solenoid is switched to the low pressure side when the solenoid is turned
ON (power supplied) and to the high pressure side when turned OFF (no power supplied).
In the forward travel range (D, 3, 2, L range), the line pressure decreases lower than that in
the P, N, and R range through the oil pressure circuit for the forward travel range.


Gear shift control The TCM issues a shift solenoid drive signal based on the traveling mode switch, inhibitor
switch, vehicle speed, throttle opening and other input signal to control the optimum gear
position automatically.
Speed change features have been set up to the TCM; the normal mode is suited to usual
traveling and the power mode is appropriate when the vehicle is loaded or accelerates the
speed.
In addition, speed change features used only for high oil temperature, hill climbing, and
down have been set up to the TCM, which are automatically switched depending on the
traveling conditions.
When the oil temperature is low (below 10
C), speed change from the third to the fourth
speed is prohibited by the gear shift control.


Shift pattern selection
control
According to a vehicle condition, the TCM selects the following shift pattern.

Selection Priority Shift Pattern 3rd Start Lamp Power Drive Lamp
High High Temperature OFF OFF
3rd Start ON
4L
Power SW Off
OFF
Down Slop Power SW On
Power ON
Up Slope
Low Normal
OFF
OFF

- High temperature mode -
High temperature mode setting condition
ATF temperature: More than 123
C
Above condition is met for more than 10 seconds.
High temperature mode cancel condition
ATF temperature: Less than 116
C
Above condition is met for more than 10 seconds.

- 3rd start mode -
3rd start mode setting condition
3rd start switch: On  Off (Pushed)
Vehicle speed: Less than 11km/h
ATF temperature: Less than 115
C
Throttle position: Less than 8%
Select lever position: D range
Above conditions are met at the same time.
3rd start mode reset condition
3rd start switch: On  Off again(Pushed again)
Vehicle speed: More than 34km/h
Select lever position: Other than D range
At least, one of above conditions is met.

7A1-30 CONSTRUCTION AND FUNCTION
LINE PRESSURE CONTROL

Either the throttle opening, vehicle speed, turbine rotational speed, ATF temperature or speed-change
range signal appropriate under the situation is issued from the TCM. The ON/OFF type line pressure
solenoid is actuated and switches the line pressure to high or low pressure.

The line pressure generated by the oil pump acts on the point A of the pressure regulator valve. When
the pressure control solenoid is turned ON by the signal from the TCM, the solenoid pressure does not
act. The line pressure is adjusted to match the spring force acting on the right side of the pressure
regulator valve.

When the pressure control solenoid is turned OFF, the solenoid pressure acts so that the line pressure is
adjusted to match the spring force acting on the right side of the pressure regulator valve.

As a result, the line pressure is adjusted to be low when the pressure control solenoid is ON and to be
high when the pressure control solenoid is OFF.

In the D, 3, 2 and L range, the line pressure through the oil pressure circuit acts onto the point B of the
pressure regulator valve and the pressure regulator valve moves so as to increase the pressure to be
drained, so that the line pressure is adjusted to be lower than the P, N, and R range by the difference of
area at the point B.




Figure 50. Line Pressure Control

LOCK-UP CONTROL

The lock-up solenoid adjusts the pressure and controls the lock-up based on the pre-set lock-up point,
according to the vehicle speed, throttle opening, engine rotations, turbine rotations and ATF temperature
input signal, based on the signal from the TCM.

Smooth lock-up control is employed to engage or disengage the clutch smoothly at the time of lock-up.

When the oil temperature is low (below 20C) or high (over 128C), lock-up is disengaged even though
the vehicle is at the lock-up speed.

The lock-up is disengaged also when the throttle is closed.

When the TCM determines the lock-up engagement, the DUTY ratio to supply power to the lock-up
solenoid is gradually increased (5% to 95%) and the oil between the lock-up piston and converter cover is
gradually drained.
As a result, the lock-up piston is fitted slowly under pressure to the converter cover securing smooth lock-
up engagement.

DIAGNOSIS (JR405E) 7A2-1
SECTION 7A2
DIAGNOSIS
TABLE OF CONTENTS
PAGE
BASIC TROUBLE SHOOTING..................................................................................................7A2-6
CHECK TRANS INDICATOR & SELF DIAGNOSIS..............................................................7A2-7
DIAGNOSIS WITH TECH 2........................................................................................................7A2-9
TECH 2 CONNECTION .................................................................................................. 7A2-9
TECH 2 OPERATING FLOW CHART (START UP)..............................................................7A2-10
TYPICAL SCAN DATA................................................................................................................7A2-13
MISCELLANEOUS TEST...........................................................................................................7A2-14
INTERMITTENT DIAGNOSIS....................................................................................................7A2-16
SNAPSHOT DISPLAY WITH TIS 2000....................................................................................7A2-17
SERVICE PROGRAMMING SYSTEM (SPS) ................................................................. 7A2-21
CIRCUIT DIAGRAM.....................................................................................................................7A2-24
PART LOCATION........................................................................................................................7A2-26
CONNECTOR LIST.....................................................................................................................7A2-31
DIAGNOSIS TROUBLE CODE TABLE...................................................................................7A2-33
FAIL-SAFE FUNCTION..............................................................................................................7A2-35
DTC P0722 (FLASH CODE 11) VEHICLE SPEED SENSOR NO SIGNAL......................7A2-36
DTC P0727 (FLASH CODE 13) ENGINE REVOLUTION SENSOR NO SIGNAL............7A2-38
DTC P0717 (FLASH CODE 14) TURBINE SPEED SENSOR NO SIGNAL......................7A2-40
DTC P0710 (FLASH CODE 15) ATF TEMPERATURE SENSOR FAILURE....................7A2-42
DTC P0560 (FLASH CODE 16) SYSTEM VOLTAGE FAILURE........................................7A2-43
DTC P0705 (FLASH CODE 17) INHIBITOR SWITCH FAILURE........................................7A2-44
DTC P1120 (FLASH CODE 22) THROTTLE SIGNAL FAILURE........................................7A2-46
DTC P1875 (FLASH CODE 25) GND RETURN CIRCUIT FAILURE.................................7A2-47
DTC P0753 (FLASH CODE 31) LOW & REVERSE BRAKE DUTY
SOLENOID FAILURE................................................................................................................7A2-48
DTC P0758 (FLASH CODE 32) 2-4 BRAKE DUTY SOLENOID FAILURE......................7A2-51
DTC P0763 (FLASH CODE 33) HIGH CLUTCH DUTY SOLENOID FAILURE................7A2-54
DTC P0768 (FLASH CODE 34) LOW CLUTCH DUTY SOLENOID FAILURE................7A2-57

DIAGNOSIS (JR405E) 7A2-33
DIAGNOSIS TROUBLE CODE TABLE

Flash Code
(P-Code)

CHECK TRANS Flash Pattern

Description
CHECK
TRANS
Warning

11 (P0722) Vehicle Speed Sensor No Signal ON


12 (-) Normal -


13 (P0727) ON

Engine Revolution Sensor No
Signal

14 (P0717) Turbine Speed Sensor No Signal ON


15 (P0710) ATF Temperature Sensor FailureOFF


16 (P0560) System Voltage Failure ON


17 (P0705) Inhibitor Switch Failure ON


22 (P1120) Throttle Signal Failure ON


25 (P1875) GND Return Circuit Failure ON


26 (P1853) ON

Low & Reverse Brake Pressure
Switch Failure

27 (P1858) 2-4 Brake Pressure Switch FailureON


28 (P1863) ON

High Clutch Pressure Switch
Failure

31 (P0753) ON

Low & Reverse Brake Duty
Solenoid Failure

32 (P0758) 2-4BrakeDutySolenoidFailure ON


33 (P0763) ON
High Clutch Duty Solenoid Failure

DIAGNOSIS (JR405E) 7A2-35
FAIL-SAFEFUNCTION
Fail-Safe Condition
Flash Code
(P-Code)

Description
CHECK
TRANS
Warning

Gear Shift
Solenoid
Line
Pressure
Solenoid

Lock-up

Remark
11
(P0722)
Vehicle peed Sensor No
Signal ON 3rdFix All Stop - Inhibited
13
(P0727)
Engine Revolution Sensor
No Signal ON - - - Inhibited
14
(P0717)
Turbine Speed Sensor No
Signal ON 3rdFix All Stop - Inhibited
15
(P0710)
ATF Temperature Sensor
Failure OFF 3,2,L - - Inhibited*1
16
(P0560)
System Voltage Failure ON 3rdFix All Stop - Inhibited*2
17
(P0705)
Inhibitor Switch Failure ON 3rdFix All Stop - Inhibited
22
(P1120)
Throttle Signal Failure ON 3rdFix All Stop - Inhibited
25
(P1875)
GND Return Circuit
Failure ON 3rdFix All Stop - Inhibited*2
26
(P1853)
Low & Reverse Brake
Pressure Switch Failure ON No Fail-safe Function
27
(P1858)
2-4 Brake Pressure
Switch Failure ON No Fail-safe Function
28
(P1863)
High Clutch Pressure
Switch Failure ON No Fail-safe Function
31
(P0753)
Low & Reverse Brake
Duty Solenoid Failure ON 3rdFix All Stop - Inhibited
32
(P0758)
2-4 Brake Duty Solenoid
Failure ON 3rdFix All Stop - Inhibited
33
(P0763)
High Clutch Duty Solenoid
Failure ON 3rdFix All Stop - Inhibited
34
(P0768)
Low Clutch Duty Solenoid
Failure ON 3rdFix All Stop - Inhibited
35
(P0748)
Line Pressure Solenoid
Failure ON - - Stop -
36
(P1860)
Lock-up Duty Solenoid
Failure ON - - - Inhibited
41
(P0731)
1stGearRatioError ON No Fail-safe Function
42
(P0732)
2ndGearRatioError ON No Fail-safe Function
43
(P0733)
3rdGearRatioError ON No Fail-safe Function
44
(P0734)
4thGearRatioError ON No Fail-safe Function
51
(P1750)
Low & Reverse Brake
Fail-safe Valve Failure ON 3rdFix All Stop - Inhibited
52
(P1755)
2-4 Brake Fail-safe Valve
Failure ON 3rdFix All Stop - Inhibited
-
(P0602)
ECU Programming Error ON No Fail-safe Function
*1: When the engine speed is more than 470 rpm for 10 minuets, the lock-up and gear shift to 4th (over-drive) are
allowed.
*2: In case of fail-safe valve failure, gear shift to 4th (over-drive) is inhibited.

DIAGNOSIS (JR405E) 7A2-47
DTC P1875 (Flash Code 25) GND Return Circuit Failure
Control Valve



TCM

B6




B7



B8



B9


B22 (GND)
BLU/BLK
WHT/BLU
L&R Brake Solenoid

Terminal
Assembly
BLK/YEL
RED 2-4 Brake Solenoid


High Clutch Solenoid


Low Clutch Solenoid


E54
(5)

(9)


(10)


(3)

(11) H23 (11)




(5)


(7)



(2)

(1)
GRY/REDC95
(6)




(7)


(8)



(9)

(22)

BLU/BLK
BLK/YEL RED
WHT/BLU
GRY/RED



Setting Condition:

Ground return circuit is failed 7 times continuously after the low & reverse brake duty solenoid output signal turn
on.

Fail Safe:

All solenoid operations are stopped (OFF), the gear is fixed to the 3rd, and the lock-up is inhibited. (In case of
fail-safe valve failure, gear shift to 4th (over-drive) and lock-up are inhibited.)

Possible Cause:

Ground return wire open circuit between terminal assembly terminal 11 and TCM terminal B22 (C95).

Poor connection of each connector.