2004 ISUZU TF SERIES ESP

CONSTRUCTION AND FUNCTION 7A1-31


Figure 51. Lock-up Control

DIRECT ELECTRIC SHIFT CONTROL (DESC)
Feature

Based on the each switch signals (low & reverse brake pressure, 2-4 brake pressure & high clutch
pressure) and sensors signals (turbine sensor, speed sensor, engine speed signal & throttle position
signal), duty cycle type solenoid adjusts the clutch pressure to match the engine load and vehicle
traveling condition. By this result, controlling the engagement and disengagement of the clutch and brake
pressure is directly and accurately controlled via TCM, which is not realized in previous accumulator type.
Operation

Instead of the previous system (on/off type of shift solenoid and shift valve), the combination of duty cycle
type solenoid and amplifier (Amp) valve are used to adjust the clutch pressure to match the engine load
and vehicle traveling condition based on the signal from the TCM, and the pressure switch provided in the
oil passage of the control valve transmits the oil pressure condition at that time to TCM, thus controlling
the engagement and disengagement of the clutch and brake directly and finely.

When the gear is shifted from the 2nd to 3rd, 3rd to 4th (O/D), 4th (O/D) to 3rd and 3rd to 2nd, the clutch
pressure on the engagement side and that on the disengagement side are simultaneously controlled.
As a result, engine racing or clutch drag is prevented securing smooth and quick speed change response

7A2-14 DIAGNOSIS (JR405E)
MISCELLANEOUS TEST
The state of each circuit can be tested by using miscellaneous test menus. Especially when DTC cannot be
detected, a faulty circuit can be diagnosed by testing each circuit by means of these menus.
Even DTC has been detected, the circuit tests using these menus could help discriminate between a mechanical
trouble and an electrical trouble.

Connect Tech 2 and select "Powertrain", "JR 405E" & "Miscellaneous Test".
F0: Lamps
The circuit is normal if the warning light in the meter panel comes on and goes out in accordance with Tech 2
instruction.

Lamps

F0: Power Lamp Test
F1: 3rd Start Lamp Test
F2: AT Oil Tempeature Lamp Test
F3: Transmission Check Light Test


F0: Power Lamp Test


Power Lamp Test

Power Lamp Off



 Press "Active" key.
Then, "POWER DRIVE" indicator lamp is turned on in the meter panel.
 Press "Inactive" key.
Then, "POWER DRIVE" indicator lamp is turned off in the
meter panel.
 Press "Quit" Key to cancel the test.
F1: 3rd Start Lamp Test
F2: AT Oil Temperature Lamp Test
F3: Transmisstion Check Light Test
Test procedure is same as "F0: Power Lamp Test".
The circuit is normal if the warning light in the meter panel
comes on and goes out in accordance with Tech 2 instruction.

F1: Solenoids
The circuit is normal if clicking sound is generated in accordance with Tech 2 instruction.

Solenoids
F0: Low & Reverse Brake Solenoid
F1: 2-4 Brake Solenoid
F2: High Clutch Solenoid
F3: Low Clutch Solenoid
F4: Line Pressure Solenoid
F5: Lock Up Duty Solenoid

DIAGNOSIS (JR405E) 7A2-17
SNAPSHOT DISPLAY WITH TIS2000 (For Snapshot Data Analysis)
Procedures for transferring and displaying Tech2 snapshot data by using TIS2000 [Snapshot Upload] function is
described below.
Snapshot data can be displayed with [Snapshot Upload] function included in TIS2000.
By analyzing these data in various methods, trouble conditions can be checked.
Snapshot data is displayed by executing the three steps below shown:


1. Record the snapshot data, in Tech2.
2. Transfer the snapshot data to PC.
After recording the snapshot in Tech2, transfer the data from Tech2 to PC by the below procedures.
1. Start TIS2000.
2. Select [Snapshot Upload] on the TIS2000 start screen.
3. Select [Upload from trouble diagnosis tool (transfer from diagnosis tester)] or click the corresponding icon of
the tool bar.
4. Select Tech2, and transfer the recorded snapshot information.
5. Select the transferred snapshot.
6. After ending transfer of the snapshot, data parameter list is displayed on the screen.

7A2-18 DIAGNOSIS (JR405E)


3. Snapshot data is displayed with TIS2000 [Snapshot Upload] function.
Snapshot is stored in the PC hard disk or floppy disk, and can be displayed any time.
Stored snapshot can be displayed by the below procedures.
1. Start TIS2000.
2. Select [Snapshot Upload] on the TIS2000 start screen.
3. Select [Open the existing files] or click the corresponding icon of the tool bar.
4. Select the transferred snapshot.
5. Open the snapshot, to display the data parameter list on the screen.
Graph display
Values and graphs (Max. 3 graphs):
1. Click the icon for graph display. [Graph Parameter] window opens.
2. Click the first graph icon of the window upper part, and select one parameter from the list of the window lower
part. Selected parameter is displayed nest to the graph icon. Graph division can be selected in the field on the
parameter right side.
3. Repeat the same procedures with the 2nd and 3rd icons.
4. After selecting all parameters to be displayed (Max. 3 parameters), click [OK] button.

DIAGNOSIS (JR405E) 7A2-45

Setting Condition:

No range signal is entered from the inhibitor switch with the engine speed over 500 rpm for 2 seconds.
Or

Multiple signals are entered from the inhibitor switch for 1 second.

Fail Safe:

When the vehicle is running, the gear position selected at the trouble detection is held and the lock-up is
inhibited.

After the vehicle stopped, all solenoid operations stop (OFF) and the gear is fixed to the 3rd.

Possible Cause:

Inhibitor switch incorrect adjustment.

Inhibitor switch malfunction.

Open circuit or short circuit to battery between inhibitor switch terminal 2 and TCM terminal A2 (C94), terminal 4
and TCM terminal B19 (C95), terminal 8 and TCM terminal B10 (C95), terminal 5 and TCM terminal B11 (C95),
terminal 1 and TCM terminal A17 (C94), terminal 9 and TCM terminal B2 (B95), or terminal 6 and TCM terminal
B21 (C95), or short between respective harness.

Power supply wire open circuit or short circuit to ground between inhibitor switch terminal 3 and power supply
circuit.

Poor connection of each connector.


Reference:
Following continuity can be measured by circuit tester.

10 7 3 2 4 8 5 1 9 6
P
R
N
D
3
2
L

7A2-76 DIAGNOSIS (JR405E)
DTC P0731 (Flash Code 41) 1st Gear Ratio Error
DTC P0732 (Flash Code 42) 2nd Gear Ratio Error
DTC P0733 (Flash Code 43) 3rd Gear Ratio Error
DTC P0734 (Flash Code 44) 4th Gear Ratio Error

Pre-setting Condition:

No other DTCs.

2 seconds elapsed after D, 3, 2, or 1 range was selected.

Vehicle is running at the vehicle speed over 10 km/h with the turbine speed over 1000 rpm.

Except at the gear shifting.

ATF temperature more than 60C.

No fail safe valve malfunction.

Setting Condition:
In the case pre-setting conditions are met, the TCM calculates the turbine speed that corresponds to the gear ratio
of the outputted solenoid pattern in about 7 seconds after each gear shift has completed, and when the output shaft
speed against the turbine speed exceeds 500 rpm.

Fail Safe:

No fail safe function

Possible Cause:

Turbine sensor or speed sensor malfunction.

Shift solenoid malfunction.

Clutch slipping.

Step Action Yes No
1 Turn the key switch on and check the DTC. Are the DTC other
than gear ratio error outputted? Go to Other DTC
Section Go to Step 2
2 Clear the DTC from the memory. Turn the key switch off once,
and then start the engine. Does the CHECK TRANS blink
when the gear shift is repeated 3 times from 1st to 4th in the D
range? Go to Other DTC
Section Go to Step 3
3 Check again the DTC. Are all codes indicating gear ratio error
outputted?

Even if one of DTC
indicating gear ratio
error is outputted
Go to step 5

Go to Step 4
DTC indicating gear
ratio error are not
outputted at all.
Go to step 9
4 Check the turbine sensor and the speed sensor for function. Is
the result OK?
Go to Step 9
Replace turbine speed
sensor.
Go to Step 9
5 Are the color and smell of ATF normal? Go to Step 6 Go to Step 9

DIAGNOSIS (JR405E) 7A2-77
Step Action Yes No
6 Is the quantity of ATF correct?
Go to Step 7
Correct the quantity of
ATF.
Go to Step 9
7 Connect the Tech 2 and test the solenoids of respective
solenoids for low & reverse brake, 2-4 brake, high clutch and
low clutch. Is operation sound heard from each solenoid?
Go to Step 8
Replace the solenoid
that does not generate
the operation sound.
Go to Step 9
8 Check the line pressure during the idling and at the engine stall
speed. Is the line pressure correct?
Go to Step 10
Either control valve, oil
pump or power train
parts (clutch, brake)
will be faulty. Replace
or overhaul the
transmission unit.
Go to step 10
9 Run the vehicle, and is the gear shifted from 1st to 4th
correctly?
Go to Step 10
Either control valve, oil
pump or power train
parts (clutch, brake)
will be faulty. Replace
or overhaul the
transmission unit.
Go to step 10
10 Clear the DTC from the memory and perform the work after
repair. Is the same DTC code outputted again in the
subsequent DTC check?
Replace the TCM Go to Step 11
11 Are the other DTCs outputted?
Go to Other DTC
Section Action is completed

DIAGNOSIS (JR405E) 7A2-115
No. D1: Faulty Gear Shifting (Different from Shift Pattern)

Description:

Gear is shifted, different from the specified shift pattern.

Diagnosis Hints:

When inspecting faulty gear shifting, it is important to distinguish between the fault of electric system and
mechanical system (AT main unit).

Fault of electric system.
Monitor the output signal (each solenoid driving signal) using with Tech 2. If a trouble signal is sent to the solenoid synchronously with the faulty gear shifting, the fault is originated in the electric system.
Monitor the input signal (signal from each sensor) using with Tech 2 and find an input signal by which the output signal (each solenoid driving signal) is subjected to fault.
Fault of the electric system may be derived from temperature or vibration. For instance, though the engine is normal while it is cold, fault may occur when the engine is warmed up or vehicle is running.

Fault of mechanical system.
If the gear is incorrectly shifted irrespective of operating signal (ON-OFF) of each solenoid, the faulty is originated from the machine system (AT).
If the clutch slips, ATF smells burnt, contaminated to be black or the stall speed increases.

Possible Cause:

Disordered select cable.

Disordered inhibitor switch.

Slip of clutch.
If slip of clutch is caused, a DTC (gear ratio error) is stored.

Fixing at 3rd position (fail-safe activated)
Since the gear is fixed at the 3rd position because of the fail-safe function, a trouble that "Faulty gear shifting" is resulted. In this case, the DTC is memorized.
When TCM stops operation because of faulty TCM ground, the gear is fixed at the 3rd position because
of a mechanical reason. In this case, no DTC is memorized.







Incorrect properties of throttle opening signal (serial communication) of throttle position sensor.
The throttle opening signal which is sent by serial communication from ECM and TCM is an important
signal for gear shifting. In case of ECM fault or when the throttle position sensor does not issue voltage
signal according to the throttle opening, the gear is not shifted by stepping over the accelerator.
If the output voltage of the throttle position sensor changes freely even though the throttle opening is
constant, the gear is shifted incorrectly.




Faulty speed sensor.