ISUZU TROOPER 1998 Service Repair Manual

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±70
StepNo Ye s Action
141. Turn off the starter switch.
2. Disconnect the ECU connector.
When the transfer lever is shifted to the neutral position, is the
continuity established between terminals (B±68)3 and (B±67)11
(4H switch)?
Go to Step 15Go to Step 17
15When the transfer lever is shifted to the high position, is the
continuity established between terminals (B±68)3 and (B±67)11?
Go to Step 17Go to Step 16
16When the transfer lever is shifted to the 4L position, is the
continuity established between terminals (B±68)3 and (B±67)11?The ECU has
failed. Replace
the ECU.
Go to Step 23
Go to Step 17
171. 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)6 and (B-68)3?
Go to Step 18Go to Step 20
18When the transfer lever is shifted to the high position, is the
continuity established between transfer connector terminals
(H-49)6 and (B-68)3?
Go to Step 20Go to Step 19
19When the transfer lever is shifted to the 4L position, is the
continuity established between transfer connector terminals
(H-49)6 and (B-68)3?
Go to Step 20
GND is
short-circuited
between
terminals (B-68)3
and (H-49)6.
Repair the circuit.
Go to Step 23
201. 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)4 and (B-68)3?
Go to Step 21
Repair the
transfer
assembly.
Go to Step 23
21When the transfer lever is shifted to the high position, is the
continuity established between terminals (A-3)4 and (B-68)3?Repair the
transfer
assembly.
Go to Step 23
Go to Step 22
22When the transfer lever is shifted to the 4L position, is the
continuity established between terminals (A-3)4 and (B-68)3?
Repair the
transfer
assembly.
Go to Step 23
GND is
short-circuited
between
terminals (B-68)3
and (A±3)4.
Repair the circuit.
Go to Step 23
23Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 23

4B2±71 DRIVE LINE CONTROL SYSTEM (TOD)
Chart D±14L switch circuit wires are broken or the battery is short-circuited.
Function of circuitÐ
Fail conditionThe TOD mode is displayed in the neutral position between high and 4L. When the lever
is shifted to the 4L position, the TOD mode is displayed.
Indicator lamp status
Transfer position4LNeutral
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DRIVE LINE CONTROL SYSTEM (TOD) 4B2±72
StepActionYe sNo
1Turn on the starter switch.
When 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 4
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 4
3When the transfer lever is shifted to the 4L position, is 0V
observed between terminals 9 and 19 (4L switch)?The ECU has
failed. Replace
the ECU.
Go to Step 4
Go to Step 4
41. Turn off the starter switch.
2. Disconnect the ECU connector.
3. Turn on the starter switch.
When the transfer lever is shifted to the high position, is 12V
observed between terminals (B±68)4 and (B±67)11?
Go to Step 5Go to Step 7
5When the transfer lever is shifted to the neutral position, is 0V
observed between terminals (B±68)4 and (B±67)11?
Go to Step 6Go to Step 7
6When the transfer lever is shifted to the 4L position, is 0V
observed between terminals (B±68)4 and (B±67)11?The 4L switch
circuit battery is
short-circuited
between ECU
and transfer.
Repair the circuit
Go to Step 13
Go to Step 7
7Turn off the starter switch.
When the transfer lever is shifted to the high position, is the
continuity established between terminals (B±68)3 and (B±67)11?
Go to Step 10Go to Step 8
8When 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 9Go to Step 10
9When the transfer lever is shifted to the 4L position, is the
continuity established between terminals (B±68)4 and (B±67)11?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 13
Go to Step 10
101. Disconnect the A±3 connector.
When the transfer lever is shifted to the neutral position between
high and 4L, is the continuity established between transfer
connector terminals (A±3)12 and GND?Wires are broken
between transfer
connector (A±3)
and floor
connector (H-49).
Repair the circuit.
Go to Step 11
Repair the
transfer
assembly.
Go to Step 13
11When the transfer lever is shifted to the 4L position, is the
continuity established between transfer connector terminals
(A±3)12 and GND?
Go to Step 12
Repair the
transfer
assembly.
Go to Step 13
12When the transfer lever is shifted to the high position, is the
continuity established between transfer connector terminals
(A±3)12 and GND?Repair the
transfer
assembly.
Go to Step 13
Go to Step 13
13Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 13

4B2±73 DRIVE LINE CONTROL SYSTEM (TOD)
Chart D±2The 4L switch circuit is short-circuited to GND.
Function of circuitÐ
Fail conditionThe 4L mode is displayed even in the 2H or TOD.
Indicator lamp status
Transfer positionHIGH (2H or 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±75 DRIVE LINE CONTROL SYSTEM (TOD)
StepNo Ye s Action
14When the transfer lever is shifted to the 4L position, is the
continuity established between terminals (A-3)12 and GND?
Go to Step 15
Repair the
transfer
assembly.
Go to Step 16
15When the transfer lever is shifted to the high position, is the
continuity established between terminals (A-3)12 and GND?
Repair the
transfer
assembly.
Go to Step 16
GND is
short-circuited
between
terminals (H±49)5
and (A-3)12.
Repair the circuit.
Go to Step 16
16Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 16

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±76
Chart E±1AXLE switch circuit wires are broken.
Function of circuitÐ
Fail conditionBoth the TOD and 4L modes are disabled. (The transition status is not removed.)
Indicator lamp status
Transfer positionTOD4L
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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
D04RW063