2002 ISUZU AXIOM instrument panel

INTELLIGENT SUSPENSION3F±23
DTC5 Vehicle Speed Sensor Open Circuit or Short
Circuit Description
Output speed information is provided to the control unit by
the vehicle speed sensor. The vehicle speed sensor
produces a pulsing AC voltage. The AC voltage level and
number of pulses increases as the speed of the vehicle
increases. The control unit then converts the pulsing
voltage to vehicle speed.
Diagnostic Aids

Inspect the wiring for poor electrical connections
between the control unit 48 way connector and the
speed sensor connectors. Look for possible bent,
backed out, deformed, or damaged terminals. Check
for weak terminal tension as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.
DTC5 Vehicle Speed Sensor Open Circuit or Short
StepActionValue(s)Ye sNo
11. Jack up and support the rear axle on the stand.
2. Change the transfer mode to 2WD, using TOD
switch on instrument panel.
3. Shift the transmission lever in a forward position
and rotate the rear wheels.
Does the speedo-meter operate?
ÐGo to Step 2Go to Step 3
21. Open the throttle and rev up engine speed.
2. Using a volt meter, measure the voltage between
the meter B connector I±23 terminals 7 and 16
(GND).
Does the voltage change alternately at the specified
values?
0V and 12VGo to Step 7Go to Step 5
31. Turn off the starter switch and disconnect the
control connectors C±46 and C±44.
2. Check the continuity between the vehicle speed
sensor connector terminal 3 and meter B connector
I±23 terminal 7.
Is there continuity?
ÐGo to Step 4Go to Step 6
41. Check the continuity between the control unit
connector C±46 terminal 1 and control unit
connector C±44 terminal 48.
Is there continuity?
ÐGo to Step 5Go to Step 6
5Repair or replace the vehicle speed sensor.
ÐGo to Step 8Ð
6Repair the circuit between the vehicle speed sensor
connector terminal 3 and the meter B connector I±23
terminal 7 or the circuit between the control unit
connector C±44 terminal 48 and the speed sensor
connector terminal 3.
ÐGo to Step 8Ð

4B1±2
DRIVELINE CONTROL SYSTEM
Shift On The Fly System
Outline of Shift on The Fly System
The shift on the fly system switches between 2 wheel
drive (2WD) and 4 wheel drive (4WD) electronically by the
driver turning the TOD switch on the instrument panel.
This system will control the following operations. (Shifting
between ª4Hº and ª4Lº must be performed by TOD
switch.)
1. Transmitting the torque to the front propeller shaft.
2. Connecting front wheels to, and disconnecting them
from, the front axles by axle motor actuator.
3. Indicating on instrument panel.
4. 4WD out signal to other Electronic Brake Control
Module (EBCM).
System Diagrams
412R200008

4B2±1
DRIVE LINE CONTROL SYSTEM (TOD)
AXIOM
DRIVELINE/AXLE
DRIVELINE CONTROL SYSTEM (TOD)
CONTENTS
Service Precaution 4B2±1. . . . . . . . . . . . . . . . . . . . . .
General Description 4B2±2. . . . . . . . . . . . . . . . . . . . .
Transfer Position and Drive Mode 4B2±2. . . . . . . .
TOD Control 4B2±3. . . . . . . . . . . . . . . . . . . . . . . . . .
TOD Indicator Control 4B2±3. . . . . . . . . . . . . . . . . .
Abbreviations 4B2±3. . . . . . . . . . . . . . . . . . . . . . . . .
System Components 4B2±4. . . . . . . . . . . . . . . . . . . .
Parts Location 4B2±4. . . . . . . . . . . . . . . . . . . . . . . .
Front and Rear Speed Sensors 4B2±5. . . . . . . . . .
Electromagnetic Coil 4B2±5. . . . . . . . . . . . . . . . . . .
Multi Plate Disk Clutch Pack 4B2±5. . . . . . . . . . . .
Mechanical Lock Sleeve 4B2±5. . . . . . . . . . . . . . . .
High-Low Planetary Gear Set 4B2±6. . . . . . . . . . .
4H and 4L Switch 4B2±6. . . . . . . . . . . . . . . . . . . . . .
Transfer Connector (12-pin type) 4B2±6. . . . . . . .
Transfer Connector (8-pin type) 4B2±6. . . . . . . . .
TOD Indicator Lamps
(on the instrument panel) 4B2±7. . . . . . . . . . . . . .
Check Lamp 4B2±7. . . . . . . . . . . . . . . . . . . . . . . . . .
TOD ECU 4B2±8. . . . . . . . . . . . . . . . . . . . . . . . . . . .
High-Low Shift Motor 4B2±9. . . . . . . . . . . . . . . . . . .
Motor Position and Encoder Position Code 4B2±10
Encode Position Plate 4B2±10. . . . . . . . . . . . . . . . . .
Shift High Range and Low Range 4B2±10. . . . . . . . Functions of TOD Switch and Indicator
Lamp 4B2±11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TOD Switch and Indication of Drive Mode 4B2±11.
Check Lamp 4B2±13. . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnosis 4B2±14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Information Diagnosis 4B2±14. . . . . . . . . .
Self-diagnosis 4B2±14. . . . . . . . . . . . . . . . . . . . . . . . .
Precautions on Diagnosis 4B2±16. . . . . . . . . . . . . . .
Basic Diagnostic Flow Chart 4B2±18. . . . . . . . . . . . . .
Parts Location 4B2±19. . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Diagram 4B2±20. . . . . . . . . . . . . . . . . . . . . . . . .
Connector List 4B2±24. . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Failed Pin 4B2±26. . . . . . . . . . . . . . . . . . . . .
Connector Pin Assignment 4B2±26. . . . . . . . . . . . . .
Reference 4B2±28. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Failed TOD Control Unit Pin 4B2±30. . . . .
Tech 2 Scan Tool 4B2±32. . . . . . . . . . . . . . . . . . . . . .
Getting Started 4B2±33. . . . . . . . . . . . . . . . . . . . . . . .
Operating Procedure 4B2±33. . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Codes 4B2±35. . . . . . . . . . . . . . . .
Diagnosis from Trouble Codes 4B2±36. . . . . . . . . . . .
Trouble Diagnosis Depending on The Status
of TOD Indicator 4B2±67. . . . . . . . . . . . . . . . . . . . . . . .
Diagnosis from Symptom 4B2±102. . . . . . . . . . . . . . . . .
Service Precaution
WARNING: THIS VEHICLE HAS 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.

4B2±3
DRIVE LINE CONTROL SYSTEM (TOD)
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. The
pressing force of the clutch is controlled by changing the
duty ratio 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 and engine speed information
from the PCM, ABS control unit signal, brake switch
signal, and shift motor position information.
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
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 is the drive mode (2H, TOD, 4L,
transition). The indicator can display occasional errors
and corresponding error codes.
Abbreviations
ABS Anti-lock Brake System
ADC Axle Disconnect
(Shift on the fly system)
VB Battery Voltage
VIGN Ignition Voltage

4B2±7
DRIVE LINE CONTROL SYSTEM (TOD)
TOD Indicator Lamps (on the instrument
panel)
Inform the following items.

Bulb check

Drive mode

ABS IN status

BRAKE ON status
821R200016
Check Lamp
Inform the following items.

Bulb check

Fail (fail alarm)

Trouble code
821R200016

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±62
StepActionYe sNo
11. Turn on the starter switch.
When the motor is not moving, is the voltage between the
terminals 35 and 47 8.0 ~ 14.5V?
Go to Step 2Go to Step 3
2When the motor is not moving, is the voltage between the terminal
48 and 47 8.0 ~ 14.5V?
Go to Step 5Go to Step 3
31. Turn off the starter switch.
2. Disconnect the ECU connector (C±37) and transfer connector
(A±2).
Is there the continuity between the connector terminal (C±37) 13
and (A±2) 7?
Go to Step 4
Repair the circuit.
Go to
Step 11
4Is there the continuity between the connector terminal (C±37) 26
and (A±2) 4?
Go to Step 5
Repair the circuit
Go to
Step 11
51. Connect the ECU connector (C±37) and transfer connector
(A±2).
2. Turn on the starter switch
Is the transfer shifted to the low range from the high range?
Go to Step 6Go to Step 7
61. Is the transfer shifted to the high range from the low range.The phenomenon
is not
reproduced.
Refer to
ªTrouble
intermittently
observedº.
Go to Step 8
71. After the starter switch is turned off, turn on the starter switch.
2. Right after the TOD switch is changed to the 4L position from
the TOD position, measure the voltage for 5 seconds.
Is the voltage between terminal 48 and 47 0V while the motor is
moving and 8.0 ~ 14.5V after the motor moving stops?
Go to Step 9
Replace the
ECU.
Go to
Step 11
81. After the starter switch is turned off, turn on the starter switch.
2. Right after the TOD switch is changed to the TOD position
from 4L position, measure the voltage for 5 seconds.
Is the voltage between terminals 35 and 47 0V while motor is
moving and 8.0 ~14.5V after the motor moving stops?
Go to Step 9
Replace the
ECU.
Go to
Step 11
91. Remove the motor asm with the connector (A±2) from the
transfer.
2. Connect the ECU connector (C±37).
3. Turn on the starter switch.
When the TOD switch is changed to the 4L position from the TOD
position, does the shaft in the motor asm rotate to the Low
direction?
Go to Step 10
Replace the
high-low motor
asm.
Go to
Step 11
10When the TOD switch is changed to the TOD position from the 4L
position, does the shaft in the motor asm rotate to the High
direction?
Repair the
transfer asm.
Go to
Step 11
Replace the
high±low motor
asm.
Go to
Step 11
111. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Verify the repairReturn to Step 11
NOTE:

Confirm the operation conditions when changing high
and low range.
± The car stops. (less than 2 km/h or 1.2 mph and
engine speed less than 1500 rpm)± The AT selector position is neutral.
± The brake is applied (brake switch: ON)

Verify the completion of changing the high/low range
by the TOD indicator on the instrument panel.

4B2±63
DRIVE LINE CONTROL SYSTEM (TOD)
Check flowTrouble codePhenomenonStandard
1442 (P1773)Error operation was carried out
under high±low motor running.Ð
StepActionYe sNo
11. Clear the trouble code.
Is the transfer changed to the low range from the high range?
Go to Step 2Go to Step 3
2Is the transfer changed to the high range from the low range?The phenomenon
is not
reproduced.
Refer to
ªTrouble
intermittently
observedº.
Go to Step 3
3Is the trouble code memoried?
Go to Step 4
See ªDiagnosis
from Symptomº.
4Is the memory DTC42 (P1773)?
Go to Step 5
Remove the
trouble
associated with
codes except
DTC 42 first.
Confirm the DTC
again.
Go to
Step 5
51. Clear the trouble code.
2. Confirm the condition and operation of the transfer range
changing and check the state of the TOD indicator. Change
the transfer to the low from the high and vice versa.
Is the transfer changed to the low from the high and to the high
from the low?The transfer is
changed in both
ranges by the
correct operation.
Operate the
transfer
according to
ªOwner's
Manualº.
Go to Step 6
6Is the trouble code memoried?
Go to Step 7
See ªDiagnosis
from Symptomº.
7Is the memory DTC 42 (P1773)?
Replace the
ECU.
Go to
Step 8
Remove the
trouble
associated with
codes except
DTC 42 first.
Confirm the DTC
again.
Go to
Step 5
81. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Verify the repair.Go to Step 8
NOTE:

Confirm the operation conditions when changing
high/low range.
± The car stops. (less than 2 km/h or 1.2 mph and
engine speed: less than 1500 rpm)
± The AT selector position is neutral.
± The brake is applied (brake switch: ON)
Verify the completion of changing the high/low range
by the TOD indicator on the instrument panel.

This code does not indicate the trouble of the transfer
or ECU, and is memoried when an error operation is
carried out under high-low motor running.
Therefore this code is not memoried if the transfer is
operated according to
ªOwner's Manualº.

4B2±65
DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn on the starter switch.
Is the transfer changed to the low range from the high range?
Go to Step 2Go to Step 4
2Is the transfer changed to the high range from the low range?Go to Step 3Go to Step 5
31. Clear the trouble code.
2. Turn on the starter switch.
Is the memory DTC 55 (P1755)?
Go to Step 1
The phenomenon
is not
reproduced.
Refer to
ªTrouble
intermittently
observedº.
41. Turn off the starter switch.
2. Disconnect the ECU connector (C±37).
Is the continuity between the terminals ranged within the any case
(case1, 2 or 3) in the following table (1)?
Go to Step 8Go to Step 6
51. Turn off the starter switch.
2. Disconnect the ECU connector (C±37).
Does the continuity between the terminals comply with the
following table (2)?
Go to Step 8Go to Step 7
61. Turn off the starter switch.
2. Disconnect the transfer connector (A±2).
Is the continuity between the male terminals ranged within the any
case (case1, 2 or 3) in the following table (3)?
Go to Step 8
The encoder has
failed. Replace
the high-low
motor asm.
Go to
Step 9
71. Turn off the starter switch.
2. Disconnect the transfer connector (A-2).
Does the continuity between male terminals comply with the
following table (4)?
Go to Step 8
The encoder has
failed. Replace
the high-low
motor asm.
Go to
Step 9
81. Turn off the starter switch.
2. Disconnect the ECU connector (C±37) and transfer connector
(A±2).
Is there the continuity between connector terminal (C±37) 4 and
(A±2) 6, (C±37) 17 and (A±2) 1, (C±37) 3 and (A±2) 2, (C±37) 16
and (A±2) 3, and (C±37) 2 and (A±2) 5?
The encoder has
failed. Replace
the high-low
motor asm.
Go to
Step 9
The circuit in
which there is no
continuity is
broken. Repair
the circuit.
Go to
Step 9
91. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Verify the repair.Go to Step 9
NOTE:

Confirm the operation conditions when changing high
and low range.
± The car stops. (less than 2 km/h or 1.2 mph and
engine speed: less than 1500 rpm)
± The AT selector position is neutral.
± The brake is applied (brake switch: ON)

Verify the completion of changing the high/low range
by the TOD indicator on the instrument panel.

When changing high/low range, start the engine to
prevent the battery dead.