4wd switch ISUZU KB P190 2007 Workshop Owner's Manual

TRANSFER CONTROL SYSTEM 7D1-19
Transfer-related indicator lamp and switch function
2H→Neutral →2H
Item 4WD
lamp 4L lamp Neutral
lamp Check
4WD
warning light 4WD
switch Actu ato r
detection (limit)
switches LS1,
LS2,
LS3. and LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral switch SOF
actuator switch Or
Axl e
dummy Remarks
2H Off Off Off Off No
operation1,0,1,0 Open Open Open -----
Neutral
start of
operation Off Off Off Off Neutral
position for 10
seconds 1,0,1,0 Open Open Open
Switch
operation sensor
Start of
operation Off Off Blinking
(2HZ) Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open
2H to 4H
while
driving
During
operation
(Synchro) Off Off
Blinking
(2HZ) Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open 2H to 4H
using
synchro
and retrial
During
operation (Passing through 4H) Off Off
Blinking
(2HZ) Off No
operation 0,0,1,1 Closed Open Closed -----
During
operation (Passing through 4H) Off Off
Blinking
(2HZ) Off No
operation 0,0,0,1
0,1,0,1 Closed Open Closed 4H to 4L
while
driving
During
operation
(N)
Off Off Blinking
(2HZ) Off No
operation
0,0,0,1
0,1,0,1 Closed Closed Closed
4H to 4L
through
neutral
During
operation (N) Off Off
Blinking
(2HZ) Off No
operation 0,1,0,0 Closed Closed Closed Switch
operation sensor
Neutral Off Off On Off No
operation0,1,0,0 Closed Closed Open -----
2H start of
operation Off Off On Off 2H
position for 10
seconds 0,1,0,0 Closed Open Closed
Switch
operation sensor
During
operation (Passing through N) Off
Blinking
(2HZ) Off Off No
operation 0,1,0,0 Closed Closed Closed 4L to 4H
through neutral
During
operation Off Blinking
(2HZ) Off Off No
operation 0,1,0,1
0,0,0,1 Closed Closed Closed 4L to 4H
while
driving

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7D1-20 TRANSFER CONTROL SYSTEM
Item 4WD
lamp 4L lamp Neutral
lamp Check
4WD
warning light 4WD
switch Actu ato r
detection (limit)
switches LS1,
LS2,
LS3. and LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral switch SOF
actuator switch Or
Axl e
dummy Remarks
During
operation (4H
waiting) Off
Blinking
(2HZ) Off Off No
operation 0,0,1,1 Closed Closed Closed 4L to 4H
while
waiting
During
operation (Axle) Blinking
(2HZ) Off Off Off No
operation 0,1,1,1
0,1,1,0
0,0,1,0
1,1,1,0 Closed Open Closed
2H to 4H
while
driving
During
operation (Axle) Blinking
(2HZ) Off Off Off No
operation 0,1,1,1
0,1,1,0
0,0,1,0
1,1,1,0 Open Open Closed
Axle
driving
Axle
waiting
Blinking
(2HZ) Off Off Off No
operation1,0,1,0 Open Open Closed -----
2H Off Off Off Off No
operation1,0,1,0 Open Open Open -----

• Operational restrictions (vehicle speed, engine speed, and transmission position) are applicable to transfer shifts
in both directions (H ←→Neutral ←→L).

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

TRANSFER CONTROL SYSTEM 7D1-51
Trouble diagnosis based on the operation switch, transfer indicator lamp and operating
sound “Check 4WD” indicator ON (operation guard based on the transfer actuator
position detection error)
This condition indicates a faulty circuit related with the detection (limit) switches of the system actuator.
Detection (limit) switches detect the actuator operating angle based on their combinations.
The controller monitors transition of the actuator based on the combination of the detection (limit) switch output.
If the transition based on the combinations indicates some trouble, it is memorized, and shifting operation is
stopped when the trouble is counted 5 times, and the “Check 4W D” indicator lights up. At this time, the system
permits operation to 2H only.
W hen such a condition occurs, inspection of the transfer shift actuator, checking of the harness related with the
detection (limit) switch, and erasure of the memory of the controller is required.
(Refer to the memory erasure procedure for the erasure of the memory.)
At this time, the position indicator may flash at 4Hz. It means that a detection (limit) switch trouble wad detected
in the operation process shown by that position indicator (example: 4W D indicator when shifting from 2H to 4H).

Caution:
During trouble diagnosis and correction, do not turn ON the ignition with the harness connector of the
transfer actuator disconnected. (Do not disconnect the harness connector of the transfer actuator when
the ignition is ON.)
If the controller is connected during this condition, a limit SW trouble is judged and the above-described
“Check 4WD” condition occurs.
This can be reset by clearing the memory.
When disconnecting the harness connector of the actuator and turning the ignition ON is required, remove
the controller at the same time or remove the IG power fuse of the transfer controller.



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7D1-54 TRANSFER CONTROL SYSTEM
Diagnosis from symptom
Check4WD lighting up
Step Action Yes No
1 Check what was done before the
trouble occurred.
W as the harness between the
transfer controller and actuator
disconnected with the ignition
kept ON for the purpose of
servicing the vehicle?
Or, was the ignition turned ON
(power supplied to the transfer
controller) with the harness of
the actuator removed? If the power is supplied with the
actuator not connected, a faulty
position detection switch is
considered.
Clear the memory and trace this
chart from the beginning. Go to step 2.
2
Is the ignition switch ON? Go to step 3.
Turn the ignition switch ON and
trace this chart from the
beginning.
3 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Go to step 4.
Indicator lamp burnt out.
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
4 Has the harness between the
Check4W D indicator and
transfer controller GND shorted? GND (body) short of the indicator
harness.
After repairing, trace this chart
from the beginning. Go to step 5.
5
Check the continuity of harness
between the transfer controller
and transfer actuator. Check
the power short and GND short.
Check the GND harness of the
transfer actuator.
Is a trouble noticed? Repair the harness, clear the
memory and trace this chart from
the beginning. Go to step 6.
6
Check the limit switch of the
actuator.
Is a trouble noticed? Failed actuator. Replace the
actuator, clear the memory and
trace this chart from the
beginning. Clear the memory and trace this
chart from the beginning.
Failed controller.
Replace the controller, clear the
memory and trace this chart from
the beginning.
To check the operation after completing the repair and clearing the memory, shift between 2H and 4L at least 5
times.
To judge the condition more quickly, ask the customer what happens when the Check4W D lamp lights up.
W hen the position indicator blinks at a frequency of 4Hz immediately after trouble occurs, the position of failure
which the indicator shows may be limited.
(Since it indicates the situation immediately before detection of failure, whether the vehicle is running or at a
standstill, the possibility of failure around that point is high.)
Status of the transfer when the Check4W D lights up is not always the same. Immediately after failure occurs, 2H
can be operated.



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

TRANSFER CONTROL SYSTEM 7D1-55
Cannot shift from 2WD to 4H or 4L.
When shifting from 2H to other position, the indicator (4WD, 4Lo, Check4WD, neutral)
does not respond.
Step Action Yes No
1 Is the ignition switch ON? Go to step 2.
Turn the ignition switch ON and
trace this chart from the
beginning.
2 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Failed operation switch. Or,
Failed controller. Indicator lamp burnt out.
Disconnected harness wire.
After repairing, trace this chart
from the beginning.


Even after correction step 1-1(*), 4WD indicator blinks at 4Hz and changes to 2H after 10
seconds.
Step Action Yes No
1 Is the ignition switch ON? Go to step 2.
Turn the ignition switch ON and
trace this chart from the
beginning.
2 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Go to step 3.
Indicator lamp burnt out.
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
3 After 2 seconds, check that the
Check4W D lamp is ON or OFF.
Is the Check4W D lamp OFF? Go to step 4.
Failed actuator position detection
switch (LS1, LS2, LS3, LS4,
GND).
Short or disconnection of harness
of this detection switch.
After repairing, trace this chart
from the beginning.
4 Press the 4H button.
Is sound of relay heard from the
transfer control? Go to step 5.
Failed controller.
Replace the controller and trace
this chart from the beginning.
5 Is the sound of a running motor
heard? Failed control system of the
transfer mechanism. Check and
repair and trace this chart from
the beginning. Failed actuator motor.
Disconnected controller motor
drive output circuit, GND short
circuit. +B fuse blown out.
Disconnection of that harness.
After repairing, trace this chart
from the beginning.
*Before determining a trouble (Non-trouble mode)




BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7D1-56 TRANSFER CONTROL SYSTEM
Even after the correction step 1-2(*), the 4WD indicator still blinks at 2Hz when shifting
from 2H to 4H.
Step Action Yes No
1 Check the air pressure and wear
of all the tires. Is any trouble
noticed? After adjusting the air pressure
and repairing the worn tires, try
the correction step 1-2(*). Go to step 2.
2
Check the 4W D detection switch
on the transfer case, neutral
detection switch and each
harness. Is a trouble noticed? 4W D detection switch is open or
the harness failed.
The neutral detection switch is
closed or the harness GND is
shorted.
Replace or repair and then trace
this chart from the beginning. Go to step 3.
3
Is there continuity in the harness
between the transfer controller
and front axle actuator? Has a
body short or disconnection
been detected? Go to step 4.
Body short or disconnection of
the harness between the transfer
controller and front axle actuator.
After repairing, trace this chart
from the beginning.
4 Is trouble detected in the axle
detection harness between the
axle actuator and transfer
controller? Disconnected harness.
After repairing trace this chart
from the beginning. Malfunction of axle actuator.
Refer to the paragraph of the axle
disconnect.
After repairing, trace this chart
from the beginning.
*Before determining a trouble (Non-trouble mode)
Note:
Vehicles with manual hub and rigid hub don’t have axle actuator.
W hen the above-mentioned procedure is followed, check the harness between the axle dummy output terminal and
the axle switch input terminal of the transfer controller, instead of axle actuator.


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7D1-58 TRANSFER CONTROL SYSTEM
Transfer cannot shift to another position (Except “Check 4WD” failure).
When shifting to another position, indicator (4WD, 4Lo, Check4WD, neutral) does not
respond (Current condition keeping).
Step Action Yes No
1 Is the ignition switch ON? Go to step 2.
Failed indicator and harness
(W hen lighting).
After repairing, trace this chart
from the beginning.
2 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Go to step 3.
All indicators are burnt out
(Check for GND short circuit
between the indicator and
transfer controller).
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
3 Press the other positions button.
Is the sound of relay heard from
under the seat, and the sound of
a running motor heard? Failed controller.
After replacing the controller,
trace this chart from the
beginning. *Failed operation switch. Or
harness for the operation switch
has disconnected or shorted.
* The operation switch is an analog type switch which reads the internal composite resistance value at the time of operation. If an abnormal value is detected, it is kept at the home position (The position before operating it).



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

TRANSFER CONTROL SYSTEM 7D1-59
Even after the correction step 2-1(*), the 4WD indicator still blinks at 2Hz when shifting
from 4H to 2H.
Step Action Yes No
1 Check all the tires for air
pressure and wear. Is any
trouble detected? After adjusting the air pressure
and repairing the worn tires, try
the correction step 2-1(*). Go to step 2.
2
Check the 4W D detection switch
on the transfer case and neutral
detection switch and each
harness. Is a trouble detected? 4W D detection switch is closed
or the GND short of harness.
The neutral detection switch is
closed or the harness GND has
shorted.
Replace or repair and then trace
this chart from the beginning. Go to step 3.
3
Is there continuity in the harness
between the transfer controller
and axle actuator?
Has a short or disconnection
been detected?
Is the connection incorrect? Go to step 4.
Body short, disconnection or
incorrect connection of the
harness between the transfer
controller and actuator.
After repairing, trace this chart
from the beginning.
4 Is trouble detected in the axle
detection harness between the
axle actuator and transfer
controller? GND short of harness
Malfunction of axle actuator.
Refer to the paragraph of axle
disconnect.
After repairing, trace this chart
from the beginning.
*Before determining a trouble (Non-trouble mode)

Note:
Vehicle with manual hub and rigid hub don’t have axle actuator.
W hen the above-mentioned procedure is followed, check the harness between the axle dummy output terminal and
the axle switch input terminal of the transfer controller, instead of axle actuator.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ELECTRICAL-BODY AND CHASSIS 8A-513
2WD-4WD Switch
REMOVAL AND INSTALLATION

RTW 780SH002001

Removal
1. Remove the center cluster ASM
2. Disconnect the connector.
3. Remove the 2WD-4WD switch.

Installation
To install, follow the removal steps in the reverse order.



BACK TO CHAPTER INDEX TO MODEL INDEXISUZU KB P190 2007