OPEL FRONTERA 1998 Workshop Manual

4B1–36
DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
4WD Control Unit (For Push Button Type)
4WD Control Unit Associated Parts
412RW044
Legend
(1) Lower Cluster Assembly
(2) Front Console Assembly(3) Harness Connector
(4) Nut
(5) 4WD Control Unit

4B1–37 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
Removal
1. Remove lower cluster assembly and front console
assembly.
Refer to Interior Trim in Body and Accessories
section.
2. Remove nut.
3. Remove 4WD control unit.
4. Disconnect harness connector (1).
412RW045
Legend
(1) Harness Connector
Installation
1. Connect harness connector, then install 4WD control
unit.
2. Install lower cluster assembly and front console
assembly.

4B1–38
DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
MEMO

4B2–1 DRIVE LINE CONTROL SYSTEM (TOD)
DRIVELINE/AXLE
DRIVELINE CONTROL SYSTEM (TOD)
CONTENTS
Service Precaution 4B2–1. . . . . . . . . . . . . . . . . . . . . .
General Description 4B2–2. . . . . . . . . . . . . . . . . . . . .
System Components 4B2–4. . . . . . . . . . . . . . . . . . . .
Parts Location 4B2–4. . . . . . . . . . . . . . . . . . . . . . . .
Functions of Indicator Lamp 4B2–8. . . . . . . . . . . . . .
Diagnosis 4B2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basic Diagnostic Flow Chart 4B2–17. . . . . . . . . . . . . .
Parts Location 4B2–18. . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Diagram 4B2–22. . . . . . . . . . . . . . . . . . . . . . . . . Connector List 4B2–34. . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Failed Pin 4B2–36. . . . . . . . . . . . . . . . . . . . .
Checking Failed TOD Control Unit Pin 4B2–39. . . . .
Diagnostic Trouble Codes 4B2–43. . . . . . . . . . . . . . . .
Diagnosis from Trouble Codes 4B2–44. . . . . . . . . . . .
Trouble Diagnosis Depending on The Status
of TOD Indicator 4B2–74. . . . . . . . . . . . . . . . . . . . . . . .
Diagnosis from Symptom 4B2–114. . . . . . . . . . . . . . . . .
Service Precaution
WARNING: IF SO EQUIPPED WITH A
SUPPLEMENTAL RESTRAINT SYSTEM (SRS),
REFER TO THE SRS COMPONENT AND WIRING
LOCATION VIEW IN ORDER TO DETERMINE
WHETHER YOU ARE PERFORMING SERVICE ON OR
NEAR THE SRS COMPONENTS OR THE SRS
WIRING. WHEN YOU ARE PERFORMING SERVICE
ON OR NEAR THE SRS COMPONENTS OR THE SRS
WIRING, REFER TO THE SRS SERVICE
INFORMATION. FAILURE TO FOLLOW WARNINGS
COULD RESULT IN POSSIBLE AIR BAG
DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2–2
General Description
C07RW014–1
TOD (Torque on Demand) system is traction state control
system to vehicle.
Transfer Position and Drive Mode
Three drive modes can be selected through operation of
4WD AUTO switch and transfer lever.
Transfer Position
4WD AUTO SWModeDrive mode
HIGHON (NORMAL)2HRear wheel drive
OFF (PUSHED)TODElectronically controlled torque split
four wheel drive
4LON/OFF4LLow-speed mechanical lock-up four
wheel drive
The electronic control unit (ECU) judges the signals from
the transfer lever and 4WD AUTO switch, and controls
the transfer drive mode and shift-on-the-fly system
status.
TOD Control
The TOD position usually drives the rear wheels, and
transmits the torque to the front wheels with the help of
electronically controlled torque split mechanism
according to running conditions encountered. The driving
force is directly transmitted to the rear wheels. This force
is split by the transfer and delivered to the front wheels.
The magnitude of the torque transmitted to the front
wheels is controlled by changing the pressing force of the
multi plate disk clutch built in the transfer unit. Thepressing force of the clutch is controlled by changing the
duty cycle to the electromagnetic coil mounted to the rear
of the clutch. When the clutch is completely disengaged,
the rear wheels are driven. When the clutch is completely
engaged, a rigid four wheel drive mode is obtained. The
torque split status is controlled continuously between the
rear wheel and four wheel drive modes. This system
includes front and rear speed sensors, and receives
throttle position sensor information from ECM.
The control unit receives signals sent from these sensors
and changes the pressing force of the multi plate disk
clutch to determine the torque distribution on the front and
rear wheels. Therefore, when the slip of the rear wheels is
increased against the current torque level in the normal
rear wheel drive mode, the control unit detects the slip

4B2–3 DRIVE LINE CONTROL SYSTEM (TOD)
condition, determines the optimum torque based on the
feedback control logic, and increases the torque to the
front wheels.
The control unit uses the signal from the throttle position
sensor to predict the future vehicle condition and the
intention of the driver with respect to acceleration and
deceleration, and determines the initial torque distribution
using these data and the information from the speed
sensors.
In case of small circle turning in the parking lot, for
example, the control unit minimizes the clutch pressing
force to restrict a braking phenomenon. When the ABS
becomes active, the control unit optimizes the clutch
pressing force to ensure stable braking.
TOD Indicator Control
The TOD indicator on the instrument panel informs the
driver of the current working status of the transfer unit.
The information consists of two items: the drive mode
(2H, TOD, 4L, transition) and the torque split status of the
TOD (torque distribution level). The indicator can display
occasional errors and corresponding error codes.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2–4
System Components
Parts Location
A07RY00002
Legend
(1) T/F Connector
(2) 4H and 4L Switch
(3) High-Low Planetary Gear Set
(4) Mechanical Lock(5) Multi Plate Disk Clutch Pack
(6) Electromagnetic Coil
(7) Rear Speed Sensor
(8) Front Speed Sensor

4B2–5 DRIVE LINE CONTROL SYSTEM (TOD)
Front and Rear Speed Sensors
The sensors are built in the transfer case, detect the
rotation of rotors directly coupled to the propeller shafts.
Thirty rectangular pulses are output per one rotation of
the propeller shaft.
261RW045
Electromagnetic Coil
Receives the duty signals from the TOD control unit and
controls the pressing force of the clutch pressure cam.
261RW044
Multi Plate Disk Clutch Pack
Transmits the torque determined by the clutch pressing
force to the front propeller shaft via the front drive chain.
262RW029
Mechanical Lock Sleeve
Couples the front and rear propeller shaft mechanically
when the transfer shaft is in the 4L position.
262RW028

DRIVE LINE CONTROL SYSTEM (TOD) 4B2–6
High-Low Planetary Gear Set
Establishes an auxiliary transmission mechanism. When
the transfer shift lever is set to the 2H or TOD position, the
reduction gear ratio is 1.000 and the corresponding
driving force is generated. When the transfer shift lever is
set to the 4L position, the reduction gear ratio is 2.480 and
the corresponding driving force is generated.
262RW030
4H and 4L Switch
Detects the shift position of the transfer from the
movement of the transfer lever and outputs signals to the
TOD control unit.
261RW002
Transfer Connector
Transmits the input and output signals of the speed
sensors, electromagnetic coil, and 4H and 4L switche to
the vehicle harness. A waterproof 12-pin type is used.
261RW046
TOD Indicator Lamps (on the instrument
panel)
Inform the following items.
Bulb check
Drive mode
ABS IN status
BRAKE ON status
821RW049

4B2–7 DRIVE LINE CONTROL SYSTEM (TOD)
Check Lamp
Inform the following items.
Bulb check
Fail (fail alarm)
Trouble code
Diesel/gasoline MAP
821RW078
TOD ECU
This control unit is mounted to the front right hand seat via
a special bracket.
F07RW029