ISUZU TROOPER 1998 Service Repair Manual

4B1±28
DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
2.Case that indicator keeps 2Hz blinking after
aforementioned Solution 3 is carried out.
Step
ActionYe sNo
1Check the air pressure and wear of all tires.
Were problems found?Try Solution 3
after adjust the
air pressure and
replace worn
tires.
Go to Step 2
2
Can the transfer lever be operated from High to 4L or vice versa?
Faults on the
harness wiring of
motor actuator.
Trace this chart
from the start
after repair or
replace.
Internal faults on
transfer case.
Disassemble the
transfer case for
check. Trace this
chart from the
start after repair
or replace.
Faults on the
motor actuator.
Trace this chart
from the start
after or replace.
Go to Step 3
3Pull out the hoses from vacuum actuator and operate 4WD
switch.
Is there negative pressure on either of hoses?
Go to Step 4
Faults on the
transfer position
switch or its
harness. Trace
this chart from
the start after
repair or replace.
Faults on the
VSV main body,
its harness or
vacuuming
system. Trace
the front axle
diagnosis chart in
this section.
After that, trace
this chart from
the start.
4Check the axle switch.
Were problems found?Internal faults on
axle switch.
Trace this chart
from the start
after replace.
Faults on Front
Axle ASM. Trace
the front axle
diagnosis chart in
this section.
After that, trace
this chart from
the start.
Short circuit
(body short) or
disconnection of
the axle harness.
Trace this chart
from the start
after repair or
replace.

4B1±29 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
3.Case that indicator's blinking changes to 4Hz
after aforementioned Solution 4 is carried out.
Step
ActionYe sNo
1
Can the transfer lever be operated from High to 4L or vice versa?
Faults on the
harness wiring of
motor actuator.
Trace this chart
from the start
after repair or
replace.
Faults on the
motor actuator.
Trace this chart
from the start
after replace.
Internal faults on
transfer case.
Disassemble the
transfer case for
check. Trace this
chart from the
start after repair
or replace.
Faults on the
4WD control unit.
Trace this chart
from the start
after replace.

4B1±30
DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
Front Axle Diagnosis

When the 4WD switch is operated from 4H to 2H,
indicator light does not go out.
Step
ActionYe sNo
1Drive slow 100 Ð 200m after a few minutesº idling.
Has indicator light gone out?
All right.Go to Step 2
2Jack up front tires.
Does the right side of front wheel rotate when the left side of front
wheel is rotated?
Go to Step 4Go to Step 3
31. Check the actuator switch.
2. Check the circuit to indicator.
Was a problem found?
Trace this chart
from the start
after repair or
replace.
Disassemble axle
ASM for check.
Trace this chart
from the start
after repair or
replace.
41. Check the VSV valve.
2. Check the circuit to VSV valve.
Was a problem found?Trace this chart
from the start
after repair or
replace.
Go to Step 5
5Is vacuum piping all right? (tank, hose, & pipe damage or trouble)
Go to Step 6
Trace this chart
from the start
after repair or
replace.
6Does actuator work all right?
Trace this chart
from the start.
Disassemble axle
ASM for check.
Trace this chart
from the start
after repair or
replace.

4B1±31 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)

When the 4WD switch is operated from 2H to 4H,
indicator light is not actuated.
Step
ActionYe sNo
1Drive slow 100 Ð 200m after a few minutesº idling.
Has indicator light actuated?
All right.Go to Step 2
2Jack up front tires.
Does not the right side of front wheel rotate when the left side of
front wheel is rotated?
Go to Step 4Go to Step 3
31. Check the actuator switch.
2. Check the circuit to indicator.
Was a problem found?
Trace this chart
from the start
after repair or
replace.
Disassemble axle
ASM for check.
Trace this chart
from the start
after repair or
replace.
41. Check the VSV valve.
2. Check the circuit to VSV valve.
Was a problem found?Trace this chart
from the start
after repair or
replace.
Go to Step 5
5Is vacuum piping all right? (tank, hose, & pipe damage or trouble)
Go to Step 6
Trace this chart
from the start
after repair or
replace.
6Does actuator work all right?
Trace this chart
from the start.
Disassemble axle
ASM for check.
Trace this chart
from the start
after repair or
replace.

4B1±32
DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
Shift on the Fly Vacuum Piping and Electric Equipment
(For Push Button Type)
Vacuum Piping Diagram
C04RW013
VSV Assembly, Actuator Assembly
412RS032
Vacuum Tank
412RS033

4B1±33 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
Inspection and Repair
Vacuum Piping
C04RW014
1. Pull out the Hose A in figure and install a vacuum
gauge.
2. Plug up Hose B in figure to prevent the leak of
vacuum.
3. Start the engine and measure vacuum 2 or 3 minutes
afterward.
4. Repeat 1) and 2) but with Hose A plugged and Hose B
pulled out.
5. If vacuum measures ±400mmHg, or if it shows a
sudden drop immediately after engine stop, inspect
the hose, tank, and pipe for damage.
NOTE: Be careful not to permit the entry of dust and
water during inspection.
6. Pull out Hose D in above illustration.
7. Plug Hose E in above illustration.
8. Make sure that Hose D in above illustration is under
atmospheric pressure.
9. Pull out Hose E and plug Hose D, and make sure that
Hose E is under atmospheric pressure.
10. If Check 8) or 9) has revealed stoppage, check and
see that there is no bend, foreign matter in the hose or
in the filter. If there is trouble, repair or replace.Check Valve
C04RS004
1. Apply vacuum from the orange colored side(1).
Vacuum:±400mmHg
2. Check leakage of vacuum.
3. Make sure that vacuum cannot be applied from the
black colored side(2).

4B1±34
DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
4. If vacuum is not applicable as much as ±400mmHg,
and if there is resistance on the intake side, replace
with a new check valve.
VSV Assembly
Inspect the vehicle side harness as follows:
412RS071
Legend
(1) Grey
(2) Blue
1. Remove connector.
2. Shift transfer lever to 2H and start the engine.
NOTE: Do not move the vehicle while inspection.
3. Make sure that there is continuity in the vehicle side of
harness. If there is no continuity, check transfer shift
switch and wiring.
Inspect both VSVs as follows:
F04RS004
1. With battery not connected (Usual).
A±C:There is continuity
B:Closed
2. With battery connected
A ± B:There is continuity
C:Closed
3. If 1) and 2) fail, replace with a new VSV.
Axle Position Switch
412RS048
1. With ball (1) being free
A ± B:There is continuity
2. With ball forced into the switch
A ± B:No continuity
3. If 1) and 2) fail, replace with a new switch.
Motor Actuator Assembly
Inspect the function of the motor actuator assembly as
follows:

4B1±35 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
1. Disassemble the motor actuator from transfer rear
case.
412RW037
Legend
(3) Shift Rod
(4) Connector
2. Connect the terminals as shown in figure.
Shift rod of the motor actuator moves and stops
at 4WD position.
412RW038
Legend
(1) 2WD
(2) 4WD
(3) Shift Rod
(4) Connector
3. Connect the terminals as shown in figure.Shift rod of the motor actuator moves and stops
at 2WD position.
412RW039
Legend
(1) 2WD
(2) 4WD
(3) Shift Rod
(4) Connector
4. If 2) and 3) fail, replace with a new motor actuator.
Transfer Position Switch
412RW040
Legend
(1) Ball
1. With ball being free.
A±B : There is continuity.
2. With ball forced into the switch.
A±B : No continuity.
3. If 1) and 2) fail, replace with a new switch.

4B1±36
DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
4WD Control Unit (For Push Button Type)
4WD Control Unit Associated Parts
412RW044
Legend
(1) Lower Cluster Assembly
(2) Front Console Assembly(3) Harness Connector
(4) Nut
(5) 4WD Control Unit

4B1±37 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
Removal
1. Remove lower cluster assembly and front console
assembly.
Refer to Interior Trim in Body and Accessories
section.
2. Remove nut.
3. Remove 4WD control unit.
4. Disconnect harness connector (1).
412RW045
Legend
(1) Harness Connector
Installation
1. Connect harness connector, then install 4WD control
unit.
2. Install lower cluster assembly and front console
assembly.