ISUZU TROOPER 1998 Service Repair Manual

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±80
StepActionYe sNo
1Start the engine.
When the transfer lever is shifted to the neutral position between
high and 4L, is 5V observed between terminals 10 and 19?
Go to Step 2Go to Step 7
2When the transfer lever is shifted to the high position and 4WD
switch shifted to 4WD position, is 0V observed between terminals
10 and 19?
Go to Step 3Go to Step 7
3When the transfer lever is shifted to the 4L position, is 0V
observed between terminals 10 and 19?
Go to Step 4Go to Step 7
4Select the 4WD SW to the 2WD position.
Is 12V observed between terminals 25 and 19?
Go to Step 5Go to Step 19
5Is 12V observed between terminals 26 and 19?Go to Step 6Go to Step 19
6Is 12V observed between terminals 27 and 19?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 19
The ECU has
failed. Replace
the ECU.
Go to Step 19
7When the 4WD SW is select to the 2WD position, is the battery
voltage observed between terminals 5 and 19?
Go to Step 8Go to Step 11
8When the transfer lever is shifted to the neutral position between
high and 4L, is the battery voltage observed between terminals 5
and 19?
Go to Step 9Go to Step 11
9When the transfer lever is shifted to the high position and 4WD
switch shifted to 4WD position, is 0V observed between terminals
5 and 19?
Go to Step 10Go to Step 11
10When the transfer lever is shifted to the 4L position, is 0V
observed between terminals 5 and 19?
Go to Step 12Go to Step 11
11Is any of the trouble codes 28, 32 and 33 recorded?Examine the
trouble based on
ªDiagnosis from
Trouble Codesº.
Go to Step 19
The ECU has
failed. Replace
the ECU.
Go to Step 19
121. Turn off the starter switch.
2. Disconnect the ECU connector.
Does the resistance between terminals (B±67)5 and (B±67)11
meet the standard, 17< R < 25 ohm?
Go to Step 13
Repair the circuit
or replace the
VSV.
Go to Step 19
131. Connect the ECU connector.
2. Turn on the starter switch.
When the 4WD SW is select to the 2WD position, is the battery
voltage supplied to each VSV?
Go to Step 14
Repair the circuit
or replace the
VSV.
Go to Step 19
14When the transfer lever is shifted to the neutral position between
high and 4L, is the battery voltage supplied to each VSV?
Go to Step 15
Repair the circuit
or replace the
VSV.
Go to Step 19
15When the transfer lever is shifted to the high position and 4WD
switch shifted to 4WD position, is 0V observed on each VSV?
Go to Step 16
Repair the circuit
or replace the
VSV.
Go to Step 19

4B2±81 DRIVE LINE CONTROL SYSTEM (TOD)
StepNo Ye s Action
16When the transfer lever is shifted to the 4L position, is 0V
observed on each VSV?
Go to Step 17
Repair the circuit
or replace the
VSV.
Go to Step 19
17Is the vacuum pressure supplied to the VSV?
Go to Step 18
Repair the
vacuum system.
Go to Step 19
18Can the single AXLE switch enable and disable the continuity?
Repair the shift
on the fly system
Refer to Section
4C ªFront Axleº.
Go to Step 19
Replace the
AXLE switch
Refer to Section
4C ªDrive Shaft
Systemº.
Go to Step 19
19Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 19

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±82
Chart GThe trouble codes are displayed.
Function of circuitÐ
Fail condition
Indicator lamp status
Transfer positionÐ
D04RW056

4B2±83 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
1Disconnect the ECU connector from ECU.
Is the continuity established between terminals (B±68)8 and
(B±67)11?
Go to Step 2
The ECU has
failed. Replace
the ECU.
Go to Step 3
2Is the self-diagnostic connector short-circuited?
Go to Step 3
Open the
self-diagnostic
connector.
Go to Step 3
31. Check that all the parts are mounted.
2. Clear the trouble codes.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Go to Step 3

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±84
Chart Hlighting switch circuit
Function of circuitReads in the status of lighting switch and reduces the indicator brightness at night.
Fail conditionEven if the lighting switch is pressed on and off, brightness does not change.
Indicator lamp status
Transfer positionAll position (example TOD mode)
D04RW056

4B2±85 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Disconnect ECU terminal.
2. Turn on the starter switch.
Is battery voltage observed between ECU terminals (B±68)1 and
(B±67)11?
Go to Step 2
Wirers are broken
lighting SW
circuit. Repair
the circuit.
Go to Step 4
2Turn lighting SW ªONº.
Is 0 V observed between ECU terminal (B±68)1 and (B±67)11?
Go to Step 3
Lighting SW
circuit battery
short. Repair the
circuit.
Go to Step 4
3Connect ECU terminal.
While the lighting switch is pressed on and off, does the
brightness of the indicator change?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº
Go to Step 4
The ECU has
failed. Replace
the ECU.
Go to Step 4
4Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 4

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±86
Diagnosis from Symptom
Troubles that are not indicated by the warning lamp are
listed in the table below. These troubles are caused by
the faults that cannot be detected by the self-diagnostic
function of the control unit.
If this type of trouble is observed, interview the customer
and conduct test runs to reproduce the trouble,cross-check the reported trouble with the listed
phenomena, and diagnose and analyze the trouble on the
item by item basis.
PhenomenaMajor causeCorrective action
1The tight corner braking is ob-
served when the vehicle is subject
to full steering.
The standard tires are not used.

The tire pressure is incorrect.

The tires are worn inuniformity.

The transfer or wiring is
imperfect.

The limited slip differential is
failed.Check and recondition the ve-
hicle according to Chart 1.
2Even if the 4WD SW is select to the
4WD position, the 4WD mode is not
active, resulting in remarkable rear
wheel spin.
The transfer or wiring is
imperfect.

The shift on the fly system is
failed.Check and recondition the ve-
hicle according to Chart 2.
3
When the 4WD SW is select to
the 4WD position, the drive
resistance of the 4WD system is
too large to get sufficient running
speed.

Noised drive line.
The standard tires are not used.

The tire pressure is incorrect.

The tires are worn inuniformity.

The transfer or wiring is
imperfect.

The limited slip differential is Check and recondition the ve-
hicle according to Chart 1.
4The shift on the fly system (front
axle) generates gear noises.
The wiring is imperfect.

The full automatic free wheel
hub is failed.Check and recondition the ve-
hicle according to Chart 3.
5The braking distance gets long
even when the ABS is active.
The wiring is imperfect.

The ABS is failed.Check and recondition the ve-
hicle according to Chart 4.

4B2±87 DRIVE LINE CONTROL SYSTEM (TOD)
Chart 1The tight corner braking is observed.
Function of circuitÐ
Fail conditionWhen the vehicle is subject to full steering in the TOD mode, the drive resistance gets
large or the judder occurs. Otherwise, the above phenomenon is observed only when the
brake is applied.
D04RW057

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±88
StepActionYe sNo
1Are the front and rear tires in specified size?
Go to Step 2
Replace the tires
with specified
ones, and service
the new tires.
Go to Step 16
2Is the tire pressure correct?
Go to Step 3
Replace the tires
with specified
ones, and service
the new tires.
Go to Step 16
3Are the tires free from abnormal wear?
Go to Step 4
Replace the tires
with specified
ones, and service
the new tires.
Go to Step 16
4Are different types of tires used?
Go to Step 5
Replace the tires
with specified
ones, and service
the new tires.
Go to Step 16
51. Start the engine.
2. Shift the transfer lever to the high (TOD) position.
3. Fully turn the steering to the left (or right) end, and select the D
range and start the creep run.
Does the tight corner braking occur? Is the judder with chug-chug
sound observed? * Use caution on the operation.
Go to Step 6 Go to Step 11
61. Shift the transfer lever to the 2H position.
2. Fully turn the steering to the left (or right) end, and select the D
range and start the creep run.
Does the tight corner braking occur? Is the judder with chug-chug
sound observed? * Use caution on the operation.
Go to Step 7 Go to Step 14
7Is an LSD mounted to the rear differential? Go to Step 8 Go to Step 9
8Is the genuine LSD oil used in the rear differential?
Go to Step 9
Replace the
differential oil.
Go to Step 16
9Does the engine output the power correctly?
Go to Step 10
Check the
engine.
Go to Step 16
10Do the speed sensors work correctly? (Check trouble codes.)The ECU has
failed. Replace
the ECU.
Go to Step 16
Replace the
speed sensors.
Go to Step 16
11Is the tight corner braking observed only when the brake is
applied?
Go to Step 12
Conduct full
steering under
WOT.
Go to Step 5
121. Turn off the starter switch.
2. Disconnect the ECU connector.
Is the battery voltage observed between terminals (B±68)6 and
(B±67)11?
Go to Step 13
Repair the circuit
of terminal 6
(ABS IN).
Go to Step 16

4B2±89 DRIVE LINE CONTROL SYSTEM (TOD)
StepNo Ye s Action
131. Apply the brake and fully turn the steering to the left (or right)
end, and start the creep run.
Does the voltage between terminals 4 and 20 range between 0.1
and 1.0V?Repair the
transfer
assembly.
Go to Step 16The ECU has
failed. Replace
the ECU.
Go to Step 16
141. Shift the transfer lever to the high (TOD) position.
2. Fully turn the steering to the left (or right) end, and select the D
range and start the creep run.
Does the voltage between terminals 4 and 20 range between 0.1
and 1.0V?
Go to Step 15 Go to Step 13
151. Select the 4WD SW to the 2WD position.
2. Jack up the right front wheel.
Does the front tire rotate smoothly?
Repair the
transfer
assembly.
Go to Step 16
The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 16
16Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 16
*NOTE: Before checking this item, run the vehicle more
than 10 meters with the steering wheel in straight position
so that the 4L mechanical lock sleeve can be released
certainly.