ISUZU TROOPER 1998 Service Repair Manual

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±10
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.
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Check Lamp
Check Lamp Valve Check
When the starter switch is turned on in the normal state,
the control unit turns on the CHECK lamp to check the
bulb.
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4B2±11 DRIVE LINE CONTROL SYSTEM (TOD)
The CHECK lamp also has the following functions.
D-G MAP recognition and display (The control unit
displays what type of vehicle, diesel or gasoline
vehicle, it recognizes.)
1. Short-circuit the self-diagnostic connector.
2. Turn on the starter switch. (Displays with respect to
the self-diagnosis begin to appear.)
NOTE: Do not start the engine.
3. Shift the transfer lever to the neutral position between
HIGH and 4L.
4. After all the conditions in 1 through 3 above are met,
set the throttle to the WOT (wide open throttle)
position (i.e., full open position). The display of the
self-diagnosis is temporarily suspended, and the
CHECK lamp begins to display that MAP is
recognized by the TPS (throttle position sensor)
according to the current conditions.NOTE: If the TPS has failed, this function might not work.
1. When the control unit recognizes the vehicle as
gasoline type, the CHECK lamp is turned on for five
seconds and this mode is repeated at an interval of
0.3 second.
2. When the control unit recognizes the vehicle as
diesel type, the CHECK lamp is turned off for five
seconds and this mode is repeated at an interval of
0.3 seconds.
3. Upon completion of step 4, the system resumes the
self-diagnosis. (The self-diagnosis is executed
from the beginning.)
5. Turn off the starter switch once. When above
conditions are met again in the future, the TPS MAP
control can be started.
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DRIVE LINE CONTROL SYSTEM (TOD) 4B2±12
Diagnosis
General Information Diagnosis
The troubles on TOD are classified into the group that can
be identified by the lighting status of the TOD indicator
lamps and those that can be recognized as abnormal
phenomena of the vehicle by the driver.
The troubles that can be identified by the lighting status of
the TOD indicator lamps are examined by the proceduresªDiagnosis from Trouble Codesº and ªTrouble Diagnosis
Depending on The Status of TOD indicatorº. The troubles
that can be recognized as abnormal phenomena of the
vehicle by the driver are examined by the procedure
ªDiagnosis from symptomº.
Self-diagnosis
The control unit has a function of self-diagnosis. If a
trouble occurs in the course of system startup, the control
unit blinks the CHECK lamp and saves the trouble code.
C07RW021
NOTE: If an intermittent fault occurs, the control unit
stops blinking upon removal of the fault. The trouble code
is saved to the control unit.

4B2±13 DRIVE LINE CONTROL SYSTEM (TOD)
Indication Method of Trouble Code

Short-circuit terminal 8 of the self-diagnostic
connector to GND to display the trouble code on the
CHECK lamp.
810RW308

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.
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DRIVE LINE CONTROL SYSTEM (TOD) 4B2±14
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. Shift the transfer lever to the neutral position between
HIGH and 4L, and short-circuit the self-diagnostic
connector.
NOTE: The neutral position between HIGH and 4L refers
to the point that turns off the TOD indicator lamps.
(However, be sure to check the position before
short-circuiting the self-diagnostic connector.)
C07RW011
2. Turn on the starter switch while maintaining the state
of step 1, and step on the brake pedal five times within
five seconds from the first step on. (Note that ªfive
timesº includes the first step on). (The TOD indicator
lamps display the 4L mode whenever the brake pedal
is stepped on.)
3. If the conditions shown in steps 1 and 2 are met, clear
the trouble codes saved to the control unit. (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 (e.q. 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 Filed 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 4WD
switch and shift the transfer lever 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 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. 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. Apply the brake
strongly so that the ABS works, and completely stop
the vehicle.

4B2±15 DRIVE LINE CONTROL SYSTEM (TOD)
7. Slowly start the vehicle in the 4L mode, and
accelerate to at least 20 km/h. 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 fault diagnostic procedure. If the TOD
indicator lamps are lit abnormally during the run, check
the lighting condition and give appropriate maintenance
according to the fault diagnostic procedure. Even if the
phenomena are not observed, try to reproduce the
abnormal state reported by the customer to the possible
extent.
Post-Repair Check
As long as the starter is not turned off, the TOD indicator
lamps continue blinking even after the failed control unit is
repaired. Therefore, upon completion of repair, be sure to
turn off the starter switch once and then turn on it to
conduct the test run sequence specified in steps 1
through 6 above and check that the TOD indicator lamps
no longer show any faulty status.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±16
Basic Diagnostic Flow Chart
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4B2±17 DRIVE LINE CONTROL SYSTEM (TOD)
Parts Location
D08RW621
Legend
(1) I±9
(2) B±13 or B±14
(3) H±12
(4) I±12
(5) A±3
(6) H±7, H±8
(7) H±32
(8) C±16
(9) H±5, H±6
(10) C±63
(11) H±49(12) M±22
(13) M±23
(14) M±24
(15) H±10
(16) E±5
(17) E±29
(18) H±42
(19) E±30
(20) Battery
(21) H±13, H±15, H±26
(22) Fuse Box
(23) B±67, B±68

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±18
Circuit Diagram
D04RW052

4B2±19 DRIVE LINE CONTROL SYSTEM (TOD)
D04RW053