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GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEMTF–9
TF
(2) If current is applied to the linear solenoid, the
solenoid magnetizes, and the electromagnet pull
force causes the armature to attach to the
control clutch side. Or, if there is a difference
between the rotation speed of the front and rear
wheels and the control clutch attaches, a
difference occurs in the rotation of the main cam
attached to the shaft and the control cam
attached to the front housing. As a result, each
ball pushes its cam, and the main clutch
attaches. The activation energy from the front
housing passes through main clutch to the shaft,
and then to the rear differential. Then the
activation energy is transferred to the rear
wheels.
(3) Depending on the rotation difference between
the front and rear wheels, the system controls
the current flowing to the linear solenoid. Then
the activation energy applied to the rear wheels
is smoothly controlled. Depending on the
amount of current, the restraint energy of the
outer and inner side of the main clutch changes,
and the activation energy from the propeller
shaft is smoothly controlled from a limited
condition to condition that is nearly a direct-link
4WD condition.
C128592E03
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TF–10GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEM
TF
C128594E02
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GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEMTF–11
TF
HOW TO PROCEED WITH
TROUBLESHOOTING
HINT:
• Use these procedures to troubleshoot the active torque
control 4WD system.
• *: Use the intelligent tester (with CAN VIM).
NEXT
Standard voltage:
11 to 14 V
If the voltage is below 11 V, recharge or replace the battery
before proceeding.
NEXT
(a) Use the intelligent tester (with CAN VIM) to check if the
CAN communication system is functioning normally.
Result
B
A
NEXT
(a) Check for DTCs (see page TF-16).
(b) Clear the DTCs.
(c) Recheck for DTCs.
Result
B
1VEHICLE BROUGHT TO WORKSHOP
2INSPECT BATTERY VOLTAGE
3CHECK COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM*
Result Proceed to
CAN DTC is not output A
CAN DTC is output B
Go to CAN COMMUNICATION SYSTEM
4CHECK INDICATOR LIGHT
5CHECK DTC*
Result Proceed to
DTC dose not reoccur A
DTC dose reoccur B
GO TO STEP 8
Page 1340 of 2000
TF–12GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEM
TF
A
Result
B
A
(a) Terminals of ECU (see page TF-14).
(b) DATA LIST / ACTIVE TEST (see page TF-18).
NEXT
NEXT
NEXT
6PROBLEM SYMPTOMS TABLE
Result Proceed to
Fault not listed in problem symptoms
tableA
Fault listed in problem symptoms table B
Go to step 8
7OVERALL ANALYSIS AND TROUBLESHOOTING*
8REPAIR OR REPLACE
9CONFIRMATION TEST
END
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GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEMTF–13
TF
TEST MODE PROCEDURE
1. DESCRIPTION
HINT:
When using a chassis dynamometer, brake tester, etc. to
perform a vehicle test, activate test mode to avoid a
"different tire diameter installed" incorrect judgment.
Test mode does not have a 4WD parameter. Test mode
is activated because it will prohibit a different tire
diameter judgment.
2. ACTIVATE TEST MODE
HINT:
Activate test mode before using a chassis dynamometer,
brake tester, etc. to perform a vehicle test.
(a) Check that the ignition switch is OFF.
(b) Use either of the following methods to change the
4WD ECU to test mode.
(1) Test mode activation through intelligent tester
(with CAM VIM).
• Connect the intelligent tester (with CAM VIM)
to the DLC3 connector and turn the ignition
switch ON. Using the test mode activation
function (mode 10), activate test mode.
(2) Test mode activation by shorting TS terminal
• With the ignition switch OFF, short-circuit the
TS and CG terminals of the DLC3 connector.
Then turn the ignition switch ON to activate
test mode.
NOTICE:
When the ignition switch is turned from
OFF to ON, the 4WD indicator light will
illuminate for 4 seconds. Then it will turn
off.
4WD Lock Mode indicator
HINT:
When the ignition switch is ON and the 4WD
lock switch is turned from OFF to ON, the
4WD lock mode indicator blinks twice and
then illuminates.
If the indicator does not illuminate, check the
bulb for burnout. Also, inspect the wire
harness between the 4WD ECU and
combination meter.
Control Status 4WD Control Status
During test mode Different tire diameter malfunction judgment (detection that tire
diameter of 4 wheels are not same) is not performed.
Other than above item, normal control is performed.
- 4WD lock switch OFF (4WD auto mode status)
- 4WD lock switch ON (4WD lock mode status)
4WD Lock Switch OFF Illuminates for 4 seconds, then turns
OFF
4WD Lock Switch ON Remains illuminated
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TF–14GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEM
TF
NOTICE:
If a part of the 4WD system has a defect, the
4WD indicator light will illuminate.
(c) Check if the 4WD indicator light has changed to the
test mode display.
(d) Start the engine.
3. CONFIRM MODE CHANGE
HINT:
Operate the 4WD lock switch, and check that the 4WD
control mode changes.
C128629E01
4WD Lock Switch Status 4WD Lock Mode Indicator Status 4WD Control Status
OFF Turns off 4WD auto mode
ON Illuminates 4WD lock mode
Switch changed from OFF to ON Blinks twice, then illuminates At moment of illumination, changes to 4WD
lock mode
Page 1343 of 2000

GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEMTF–15
TF
PROBLEM SYMPTOMS TABLE
HINT:
• Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms
are listed in order of probability in the "Suspected area"
column of the table. Check each symptom by checking the
suspected areas in the order they are listed. Replace parts
as necessary.
• Inspect the fuses and relays related to this system before
inspecting the suspected areas below.
Active torque control 4WD system
HINT:
*:When driving 4WD mode, the vehicle is hard to turn, as if
the brakes were applied, due to the rotational difference
between the front and rear tires while turning.
Symptom Suspected area See page
Phenomenon of tight-corner braking*1.Steering angle sensor circuitTF-27
2.Linear solenoid circuitTF-30
3.4WD control ECU
4WD indicator light remains ON 4WD indicator light circuitTF-36
4WD indicator light does not come ON 4WD indicator light circuitTF-40
The system is in the DTC output mode although
terminals TC and CG of the DLC3 are not short
circuited1.TC and CG terminal circuitTF-42
2.4WD indicator light circuit
The system is not in the DTC output mode although
terminals TC and CG of the DLC3 are not short
circuited1.TC and CG terminal circuitTF-42
2.4WD indicator light circuit
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TF–16GF1A TRANSFER – ACTIVE TORQUE CONTROL 4WD SYSTEM
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TERMINALS OF ECU
1. CHECK 4WD CONTROL ECU
(a) Measure the voltage and resistance of the
connector.
If the result is not as specified, the 4WD control
ECU may have a malfunction.
(b) Using an oscilloscope, check the waveform 1.
Waveform 1 (Reference)
G032017E06
Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
CANH (E57-14) - CANL
(E57-16)P - W CAN communication Ignition switch OFF 54 to 69
GND (E57-23) - Body
groundW-B - Body ground Ground Always Below 1
4WDL (E57-7) - Body
groundR - W-B Ground 4WD lock mode switch ON Below 1
IG1 (E57-11) - GND (E57-
23)L - W-B Power source voltage Ignition switch ON 10 to 14 V
SLC+ (E57-13) - SLC-
(E57-32)W - B 4WD linear solenoid signal Ignition switch ON Pulse generation (See
waveform 1)
BSLC (E57-9) - GND
(E57-23)R - W-B Power source voltage Ignition switch ON 10 to 14 V
C065158E02
Symbols (Terminal No.) Content
Tool setting 5 V/DIV., 2 msec. / DIV.
Vehicle condition Engine stop, ignition switch ON