1998 ISUZU TROOPER 4WD

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±62
StepActionYe sNo
11. Turn on the starter switch.
When the 4WD SW is selected to the 4WD position, is 0 V
observed between terminal 12 and 19?
Go to Step 2
Repair the 4WD
SW circuit.
Go to Step 4
2When the 4WD SW is selected to the 2WD position, is 12 V
observed between terminals 12 and 19?
Go to Step 3
Repair the 4WD
SW circuit.
Go to Step 4
3When the transfer lever is shifted to the 4L position, is battery
boltage observed between terminals 28 and 19?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 4
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

4B2±63 DRIVE LINE CONTROL SYSTEM (TOD)
Chart B±2The 4WD switch circuit is short to battery.
Function of circuitÐ
Fail conditionEven after the transfer mode is selected from 2H to TOD, the indicator lamp status dose
not change.
Indicator lamp status
Transfer positionTOD
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DRIVE LINE CONTROL SYSTEM (TOD) 4B2±64
StepActionYe sNo
1When the 4WD SW is selected to the 4WD position, is 0 V
observed between terminal 12 and 19?
Go to Step 2
Repair the 4WD
SW circuit.
Go to Step 7
2When the 4WD SW is selected to the 2WD position, is 12 V
observed between terminals 12 and 19?
Go to Step 3
Repair the 4WD
SW circuit.
Go to Step 7
31. Disconnect the ECU connector.
Is the continuity established between terminals (B±67)1 and
(B±68)13?
Go to Step 4
Replace TOD
indicator lamp
bulb.
Go to Step 7
4Is the continuity established between terminals (B±67)1 and
(B±68)14?
Go to Step 5
Replace TOD
indicator lamp
bulb.
Go to Step 7
5Is the continuity established between terminals (B±67)1 and
(B±68)15?
Go to Step 6
Replace TOD
indicator lamp
bulb.
Go to Step 7
6Is the continuity established between terminals (B±67)1 and
(B±68)16?
Replace ECU.
Go to Step 7
Replace TOD
indicator lamp
bulb.
Go to Step 7
7Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 7

4B2±65 DRIVE LINE CONTROL SYSTEM (TOD)
Chart C±14H switch circuit wires are broken or the battery is short-circuited.
Function of circuitÐ
Fail conditionWhen the 4WD SW is 4WD mode.
When the lever is shifted from 4L to HIGH, the 4L mode remains on the indicator and the
TOD mode is displayed without turning off the previous mode.
Indicator lamp status
Transfer position4L <ÐÐ> Neutral <ÐÐ> TOD
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DRIVE LINE CONTROL SYSTEM (TOD) 4B2±74
StepActionYe sNo
1When the transfer lever is shifted to the high position, is 5V
observed between terminals 9 and 19 (4L switch)?
Go to Step 2Go to Step 7
2When the transfer lever is shifted to the neutral position, is 0V
observed between terminals 9 and 19 (4L switch)?
Go to Step 3Go to Step 7
3When the transfer lever is shifted to the 4L position, is 0V
observed between terminals 9 and 19 (4L switch)?
Go to Step 4Go to Step 7
41. Shift the 4WD SW to the 2H position.
Is 12V observed between terminals 25 and 19?
Go to Step 5
The ECU has
failed. Replace
the ECU.
Go to Step 16
5Is 12V observed between terminals 26 and 19?
Go to Step 6
The ECU has
failed. Replace
the ECU.
Go to Step 16
6Is 12V observed between terminals 27 and 19?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 16
The ECU has
failed. Replace
the ECU.
Go to Step 16
71. Turn off the starter switch.
2. Disconnect the ECU connector.
When the transfer lever is shifted to the neutral position between
High and 4L, is the continuity established between terminals
(B±68)4 and (B±67)11?
Go to Step 8Go to Step 10
8When the transfer lever is shifted to the 4L position, is the
continuity established between terminals (B±68)4 and (B±67)11?
Go to Step 9Go to Step 10
9When the transfer lever is shifted to the high position, is the
continuity established between terminals (B±68)4 and (B±67)11?
Go to Step 10
The ECU has
failed. Replace
the ECU.
Go to Step 16
101. Disconnect the H-49 connector.
When the transfer lever is shifted to the neutral position between
high and 4L, is the continuity established between terminals
(H-49)5 and (B-67)11?
Go to Step 11Go to Step 13
11When the transfer lever is shifted to the 4L position, is the
continuity established between transfer connector terminals
(H-49)5 and (B-67)11?
Go to Step 12Go to Step 13
12When the transfer lever is shifted to the high position, is the
continuity established between terminals (H-49)5 and (B-67)11?
Go to Step 13
GND is
short-circuited
between
terminals (B±68)4
and (H-49)5.
Repair the circuit.
Go to Step 16
131. Disconnect the A-3 connector.
When the transfer lever is shifted to the neutral position between
high and 4L, is the continuity established between terminals
(A-3)12 and GND?
Go to Step 14
Repair the
transfer
assembly.
Go to Step 16

4B2±77 DRIVE LINE CONTROL SYSTEM (TOD)
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?The ECU has
failed. Replace
the ECU.
Go to Step 4
Go to Step 7
4Shift the transfer lever to the 4L position.
Is 0V observed between terminals 25 and 19?
Go to Step 5
The ECU has
failed. Replace
the ECU.
Go to Step 19
5Is 0V observed between terminals 26 and 19?
Go to Step 6
The ECU has
failed. Replace
the ECU.
Go to Step 19
6Is 0V 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 transfer lever is shifted to the 2H 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 (TOD mode),
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 16
131. Turn on the starter switch.
When the 4WD SW is selected 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 16
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

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±78
StepNo Ye s Action
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
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 of
Chassis Repair
Manual).
Go to Step 19
19Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 19

4B2±79 DRIVE LINE CONTROL SYSTEM (TOD)
Chart E±2The AXLE switch circuit is short-circuited to GND.
Function of circuitÐ
Fail conditionEven after the 4WD SW is select to the 2WD position, the 2WD mode is not enabled.
(The transition status is not removed.)
Indicator lamp status
Transfer position2H
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