display ISUZU AXIOM 2002 Service User Guide

3F±26INTELLIGENT SUSPENSION
DTC6 Stop Lamp Switch Open Circuit or Short (Cont'd)
StepNo Ye s Value(s) Action
9Replace the brake switch.
Is the replacement complete?
ÐGo to Step 13Ð
101. Turn the ignition ªoffº.
2. Reconnect the control unit connector C±44
Turn the ignition ªonº.
Does the brake lamp come on when the brake pedal is
applied and does it come off when the brake pedal is
released?
Ð
Go to
Diagnostic
Aids
Go to Step 11
11Check the control unit for faulty or intermittent
connections.
Was a problem found and corrected?
ÐGo to Step 13Go to Step 12
12Replace the control unit.
Is the replacement complete?
ÐGo to Step 13Ð
131. After the repair is complete, clear the DTC.
2. Conduct a test drive.
3. Review the DTC.
Has the last test failed or is the current DTC displayed?
Ð
Begin diagnosis
again
Go to
Step 1
Go to Repair
verified

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±13
DRIVE LINE CONTROL SYSTEM (TOD)
Simplified checking method of ABS IN and BRAKE ON signals:
In the event that any of the signal inputs listed below are
observed while the self-diagnostic code is being
displayed (the self-diagnostic connector is short-circuited
to GND), you can simply check the ABS IN and BRAKE
ON signals as shown in the figures below.
C07R200002
Check Lamp
Check Lamp Bulb Check
When the starter switch is turned on in the normal state,
the control unit turns on the CHECK lamp to check the
bulb.
C07RW019

4B2±15
DRIVE LINE CONTROL SYSTEM (TOD)
Indication Method of Trouble Code

Turn on the starter switch, while the engine does not
start.

Short-circuit terminal 8 of the self-diagnostic
connector to GND (terminal 4 or 5) to display the
trouble code on the CHECK lamp.
826R200011

If no trouble codes exist, code ª12º is displayed
continuously.

If trouble codes exist, code ª12º is displayed three
times, and the trouble codes, starting from the smaller
code number, are displayed three times respectively.
C07RY00018

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±16
How to Clear The Trouble Code
The trouble codes saved to the control unit can be deleted
by the following procedure if the starter switch is being in
the OFF position.
1. Short-circuit terminal 8 of the self-diagnostic
connector to GND (terminal 4 or 5).
2. Turn on the starter switch while maintaining the state
of step1, and stop short-circuiting terminal 8 to GND
within five seconds.
826R200011
3. If the conditions shown in steps 1 and 2 are met, the
trouble codes saved to the control unit are cleared.
(After the codes are completely deleted, the code 12
that indicates the normal condition is continuously
displayed.)
Precautions on Diagnosis
Replacement of Control Unit
The control unit itself rarely fails. In most cases, the
harnesses have failed (i.e. short-circuit) to cause
secondary troubles. Other cases include that the cause
has been unknown due to intermittent occurrence of
troubles and the troubles are removed accidentally along
with replacement of control unit, resulting in misjudgment
of cause. Therefore, before replacing the control unit,
check the connector joints and whether the unspecified
current flows in the control unit due to short-circuit
between harnesses.
Trouble Intermittently Observed
Troubles intermittently observed are mostly attributable
to temporary imperfect connection of harnesses and
connectors.
When such troubles are found, check the associated
circuit according to the following procedure.
1. Check whether improper connectors are plugged in
or connector terminals are completely engaged.
2. Check whether the terminals are deformed or
damaged. If yes, remove the deformation or damage
and connect the terminals securely.3. It is likely that wires in the harness are falsely broken.
Therefore, in examination of failed harness circuit,
shake the harness for check to such extent that the
harness will not be damaged.
Test Run of Failed TOD Vehicle
If the TOD indicator lamps experienced faulty operation
even once in the past, the failed portion can be identified
by use of the procedure ªDiagnosis from Trouble Codesº
or ªTrouble Diagnosis Depending on the Status of TOD
Indicatorº. If the troubles that are only recognized as
abnormal phenomena of the vehicle by the driver are
observed, conduct the test run in the following procedure
to reproduce the faulty phenomena and diagnose the fault
for each phenomenon.
1. Start the engine, and check that the TOD indicator
lamps are turned on for about two seconds for initial
check; the CHECK lamp goes off; and the TOD
indicator lamps display the specified drive mode. (If
the CHECK lamp starts blinking, read the trouble
codes and identify the failed portion.)
2. While keeping the vehicle standstill, operate the TOD
switch to change the modes: 2H mode"TOD
mode"4L mode"TOD mode"2H mode. Check
that the TOD indicator lamps correctly display the
status whenever the mode is changed. If the
transition status is displayed during the shift
operation, run the vehicle a little to complete shifting.
3. Slowly start the vehicle in the TOD mode, and add the
power to accelerate to at least 40 km/h (25 mph)and
maintain the speed for about two minutes. Apply the
brake to completely stop the vehicle. Repeat this test
pattern at least three times.
4. Turn the steering to the right end (or left end) in the
TOD mode, and slowly start the vehicle and make a
circle five times. Next, conduct the same test in the 2H
mode.
5. Slowly start the vehicle in the TOD mode, and
accelerate to at least 40 km/h (25 mph). Keep the
established speed, carefully change the mode in the
sequence ªTOD mode"2H mode "TOD modeº
while checking that the shift is complete in each mode
change. After the test, apply the brake to completely
stop the vehicle.
6. Slowly start the vehicle in the TOD mode, and
accelerate to at least 40 km/h (25 mph). Apply the
brake strongly so that the ABS works, and completely
stop the vehicle.
7. Slowly start the vehicle in the 4L mode, and
accelerate to at least 20 km/h (13 mph). Apply the
brake to completely stop the vehicle.
If the CHECK lamp starts blinking during the test run, read
the trouble codes and give appropriate maintenance
according to the diagnostic procedure. If the TOD
indicator lamps are lit abnormally during the run, check
the lighting condition and give appropriate maintenance
according to the diagnostic procedure. Even if the
phenomena are not observed, try to reproduce the
abnormal state reported by the customer to the possible
extent.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±26
Checking Failed Pin
Connector Pin Assignment

TOD control unit pin assignment
D04RY00011
No.NAMECONTENTS
1N.C Not used
2ENG REVEngine Speed
3N.CNot used
4N.CNot used
5N.C Not used
6N.CNot used
7IND.ADisplay Front
8IND. CDisplay Rear
9N.C Not used
10N.C Not used
11EMCClutch Solenoid
12REFSpeed Reference
13COM (±)Speed GND
14VIGIgnition
15TPSTPS (PWM)
16TECH 2TECH±2
17N. CNot used
18N. CNot used
19IND. BDisplay Auto
20CHK TODCheck TOD
21N.CNot used
22PWR GNDPower Ground
23ADC (+)Axle Disconnect Output
24COM GNDShift Motor Position GND
25MTR POS3Shift Motot Position 3

4B2±33
DRIVE LINE CONTROL SYSTEM (TOD)
Getting Started

Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. The Isuzu 02 System PCMCIA card (1) inserts into
the Tech 2 (4).
2. Connect the SAE 16/19 adapter (2) to the DLC cable
(4).
3. Connect the DLC cable to the Tech 2 (4)
4. Mark sure the vehicle ignition is off.
5. Connect the Tech 2 SAE 16/19 adapter to the vehicle
DLC connector.
826R200011
6. The vehicle ignition turns on.
7. Power up the Tech 2.
8. Verify the Tech 2 power up display.
060RW009
Operating Procedure
The power up screen is displayed when you power up the
tester with the Isuzu systems PCMCIA card. Follow the
operating procedure below.
060R100102

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±98
Chart GThe trouble codes are displayed.
Function of circuitÐ
Fail condition
Indicator lamp state
TOD switch positionÐ
D04R200009

5A±14BRAKE CONTROL SYSTEM
Getting Started

Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. The Isuzu 98 System PCMCIA card (1) inserts into
the Tech 2 (4).
2. Connect the SAE 16/19 adapter (2) to the DLC cable
(3).
3. Connect the DLC cable to the Tech 2 (4).
4. Make sure the vehicle ignition is off.
5. Connect the Tech 2 SAE 16/19 adapter to the vehicle
DLC.
826R200011
6. The vehicle ignition turns on.
7. Power up the Tech 2.
8. Verify the Tech 2 power up display.
060RW009
Operating Procedure
The power up screen is displayed when you power up the
tester with the Isuzu systems PCMCIA card. Follow the
operating procedure below.
060R100102

5A±16BRAKE CONTROL SYSTEM
DATA LIST
The data displayed by DATA LIST are as follows:
Display
ContentOK/NG Criteria for Data
Front Left Wheel Speed
Front Right Wheel Speed
Rear Wheel Speedskm/h (MPH)
Start the vehicle and make sure of linear change in
each wheel speed.

Turn each wheel by hand and make sure that each
speed data change.
Warning LampON/OFF
To be OFF usually
ABS StateON/OFF
To be OFF usually
ABS RelayActive/Inactive
To be Active usually
4 Wheel DriveActive/Inactive
2WD: Inactive

4WD: Active
Brake SwitchActive/Inactive
Inactive (Released)

Active (Pressed)
Brake Fluid LevelNormal or not
To be Normal usually
Return PumpActive/Inactive
To be Inactive usually
DRP (Dynamic Rear
Proportioning)Active/Inactive
To be Inactive usually
Rear Dump Valve CommandedActive/Inactive
To be Inactive usually
Rear Dump Valve Feedback
Rear Isolation Valve
Commanded
Rear Isolation Valve Feedback
FL Dump Valve CommandedActive/Inactive
To be Inactive usually
FL Dump Valve Feedback
FL Isolation Valve Commanded
FL Isolation Valve Feedback
FR Dump Valve CommandedActive/Inactive
To be Inactive usually
FR Dump Valve Feedback
FR Isolation Valve
Commanded
FR Isolation Valve Feedback
G±SensorVoltage
2.50V when vehicle is stopped
Battery VoltageVoltage
Between 10±16.9V