check engine ISUZU TF SERIES 2004 Workshop Manual

3B-56 POWER-ASSISTED STEERING SYSTEM

CAUTION: The wheel of the vehicle must be straight
ahead and the steering column in the "LOCK"
position before disconnecting the steering column
from the steering gear. Failure to do so will cause
the SRS coil assembly to become uncentered which
will cause damage to the SRS coil assembly. (with
SRS air bag)
5. Remove the engine hood opening lever and
steering lower cover.
6. Remove the driver knee bolster (reinforcement).
7. Disable the SRS (Refer to "Disabling the SRS" in
this section). (with SRS air bag)
8. Check the both side hole of the steering cover. (with
SRS air bag)
060R300025
9. Check the position of the pins in a hole. Push the
pin in the direction of an arrow. (with SRS air bag)
060R300032

10. Push the four pins at 
5
6 mm bar. (with SRS ai
r
bag)
060R300031
11. Cancel the lock four pins. (with SRS air bag)
12. Loosen the horn pad fixing screw at the rear of the
steering wheel (without SRS air bag).
430R300009

7D1-14 TRANSFER CONTROL SYSTEM
Operational limits (4H




4L) (Vehicle speed, engine speed, and transmission position not specified)

Item 4WD
lamp 4L lampNeutral
lamp Check
4WD
warning
light 4WD
switch Actuator
detection
(limit)
switches
LS1, LS2,
LS3. and
LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral
switch SOF
actuator
switch
Or
Axle
dummyRemarks
4H On Off Off Off Open 0,0,1,1 Closed Open Closed -----
4H start
of
operation On Off Off Off 4L
position
for 0.1
second 0,0,1,1 Closed Open Closed -----
10
second
display
during
limitation On Blinking
(4HZ) Off Off Open 0,0,1,1 Closed Open Closed No
operation
during
limitation
Go to 4H
after 10
seconds
On Off Off Off Open 0,0,1,1 Closed Open Closed -----

Operational limits (4L





4H) (Vehicle speed, engine speed, and transmission position not specified)

Item 4WD
lamp 4L lampNeutral
lamp Check
4WD
warning
light 4WD
switch Actuator
detection
(limit)
switches
LS1, LS2,
LS3. and
LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral
switch SOF
actuator
switch
Or
Axle
dummyRemarks
4L On On Off Off No
operation1,1,0,1 Closed Open Closed -----
4L start of
operation On On Off Off 4H
position
for 0.1
second 1,1,0,1 Closed Open Closed -----
10
second
display
during
limitation On Blinking
(4HZ) Off Off Open 1,1,0,1 Closed Open Closed No
operation
during
limitation
Go to 4L
after 10
seconds
On On Off Off No
operation1,1,0,1 Closed Open Closed -----


Under some conditions, a secondary operational indication may be received when the 4Hz operational indication
is present.

TRANSFER CONTROL SYSTEM 7D1-17
Skip operation limitations (4L




2H) (Vehicle speed, engine speed, and transmission position not
specified)

Item 4WD
lamp 4L lampNeutral
lamp Check
4WD
warning
light 4WD
switch Actuator
detection
(limit)
switches
LS1, LS2,
LS3. and
LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral
switch SOF
actuator
switch
Or
Axle
dummyRemarks
4L Off On Off Off Open 1,1,0,1 Closed Open Closed -----
4L start of
operation Off On Off Off 2H
position
for 0.1
second 1,1,0,1 Closed Open Closed -----
10
second
display
during
limitation Blinking
(4HZ) Off Off Off Open 1,1,0,1 Closed Open Closed No
operation
during
limitation
Go to 4L
after 10
seconds
Off ON Off Off Open 1,1,0,1 Closed Open Closed -----

Skip operation limitations (2H




4L) (Vehicle speed, engine speed, and transmission position not
specified)

Item 4WD
lamp 4L lampNeutral
lamp Check
4WD
warning
light 4WD
switch Actuator
detection
(limit)
switches
LS1, LS2,
LS3. and
LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral
switch SOF
actuator
switch
Or
Axle
dummyRemarks
2HL Off Off Off Off Open 1,0,1,0 Open Open Open -----
4L start of
operation Off Off Off Off 2H
position
for 0.1
second 1,0,1,0 Open Open Open -----
10
second
display
during
limitation Blinking
(4HZ) Blinking
(4HZ) Off Off Open 1,0,1,0 Open Open Open No
operation
during
limitation
Go to 2H
after 10
seconds
Off Off Off Off Open 1,0,1,0 Open Open Open -----


Under some conditions, a secondary operational indication may be received when the 4Hz operational
indication is present.

TRANSFER CONTROL SYSTEM 7D1-19
Item 4WD
lamp 4L lampNeutral
lamp Check
4WD
warning
light 4WD
switch Actuator
detectio
n (limit)
switches
LS1,
LS2,
LS3. and
LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral
switch SOF
actuator
switch
Or
Axle
dummy Remarks
During
operation
(4H
waiting) Off Blinking
(2HZ) Off Off No
operation0,0,1,1 Closed Closed Closed 4L to 4H
while
waiting
During
operation
(Axle) Blinking
(2HZ) Off Off Off No
operation0,1,1,1
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
operation0,1,1,1
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).

7D1-22 TRANSFER CONTROL SYSTEM
4L




Neutral




4L

Item 4WD
lamp 4L lampNeutral
lamp Check
4WD
warning
light 4WD
switch Actuator
detection
(limit)
switches
LS1, LS2,
LS3. and
LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral
switch SOF
actuator
switch
Or
Axle
dummyRemarks
4L On On Off Off No
operation1,1,0,1 Closed Open Closed -----
Neutral
start of
operation On On Off Off Neutral
position
for 10
seconds 1,1,0,1 Closed Open Closed -----
Start of
operation Off Off Blinking
(2HZ) Off No
operation1,1,0,0 Closed Open Closed 4L to N
while
driving
During
operation
(N) Off Off Blinking
(2HZ) Off No
operation1,1,0,0 Closed Closed Closed 4L to N
with axle
driving
During
operation
(N) Off Off Blinking
(2HZ) Off No
operation0,1,0,0 Closed Closed Closed 4L to 4N
with axle
removed
During
operation
(Axle) Blinking
(2HZ) Off Off Off No
operation0,1,0,0 Closed Closed Closed Axle
driving
Axle
waiting
Blinking
(2HZ) Off Off Off No
operation0,1,0,0 Closed Closed Closed -----
Neutral Off Off On Off No
operation0,1,0,0 Closed Closed Open -----
4L start of
operation Off Off On Off 4L
position
for 10
seconds 0,1,0,0 Open Open Open Switch
operation
sensor
During
operation
(N) Off Blinking
(2HZ) Off Off No
operation1,1,0,0 Closed Closed Open 4H to 4L
through
neutral
During
operation
(N) Off Blinking
(2HZ) Off Off No
operation1,1,0,0 Closed Closed Open 4H to 4L
through
neutral
During
operation
(N) Off Blinking
(2HZ) Off Off No
operation1,1,0,0 Closed Closed Open 4H to 4L
through
neutral
4H
waiting On Blinking
(2HZ) Off Off No
operation1,1,0,1 Closed Closed Open 4L while
waiting
During
operation
(Axle) Blinking
(2HZ) Off Off Off No
operation1,1,0,1 Closed Open Open Axle
driving
Axle
waiting
Blinking
(2HZ) Off Off Off No
operation1,1,0,1 Closed Open Open -----
4H On On Off Off No
operation1,1,0,1 Closed Open Closed -----

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

7D1-48 TRANSFER CONTROL SYSTEM
From 4H to 4L; Even after the correction step 3-3(*), 4Lo indicator blinks at 4Hz
Step Action Yes No
1 Is the ignition switch ON? Turn it OFF once. Go to step 2.
2 Turn ON the ignition switch and
check the valve. Do not start
the engine.
Has the valve check for 2
seconds been completed
normally? Go to step 3. Refer to the paragraph about the
indicator when it does not react
when shifted from 2H to 4H.
After taking the remedy, trace
this chart from the beginning.
3 Shift to 2H.
Can be shifted to 2H and then to
4H? Go to step 4. Refer to the paragraph about
shifting from 2H to 4H.
In particular, check if not at the
Check4WD condition, return to
this chart and trace it from the
beginning.
4 Set to N position in case of AT
and set to the neutral position in
case of MT and check if the
lamp blinks at 4Hz after
operation.
Failed T/M position switch and
harness (failure of TM1 and TM2
harness and their related
switches shown in the figure).
Incorrect wiring.
Repair as required and trace this
chart from the beginning. Shift back to 4H and go to step 5.
5 Start the engine and travel the
vehicle.
Does the speedometer run at
this time? Go to step 6. Failure of speed sensor or
disconnection or short of harness
(for the meter).
After repairing, trace this chart
from the beginning.
6 Check the harness between the
transfer controller and speed
sensor.
(Check the engine rotation
detection harness at the same
time.)
Is any trouble noticed? Failed harness between the
transfer controller and speed
sensor.
After repairing, trace this chart
from the beginning.
(Repair the engine rotation
detection unit, if required.) Go to step 7.
7 Travel the vehicle several
meters, stop it, meet the
permission requirements for
operation limits.
Did you wait for several seconds
after the requirements were
met? Failed controller.
Replace the controller and trace
this chart from the beginning. You did not wait for enough time.
Optimum waiting time is 1
second or maximum 3 minutes
depending on the previous
conditions.
Refer to the paragraph about
operation without failure.
*Before determining a trouble (Non-trouble mode)

TRANSFER CONTROL SYSTEM 7D1-49
From 4L to 4H: After the correction step 4-3(*), 4Lo indicator blinks at 4H.
Step Action Yes No
1 Is the ignition switch ON? Turn it OFF once. Go to step 2.
2 Turn ON the ignition switch and
check the valve. Do not start
the engine.
Has the valve check for 2
seconds been completed
normally? Go to step 3. Refer to the paragraph about the
indicator when it does not react
when shifted from 2H to 4H.
After taking the remedy, trace
this chart from the beginning.
3 Can be shifted to 2H and then to
4L? Go to step 4.
(Impossible usually.)
Failed controller In case of Check 4WD, shifting to
2H is possible.
Returning to 4L is impossible.
Refer to the paragraph about
Check4WD.
4 Set to N position in case of AT
and set to the neutral position in
case of MT and check if the
lamp blinks at 4Hz after
operation.
Failed T/M position switch and
harness (failure of TM1 and TM2
harness and their related
switches shown in the figure).
Incorrect wiring.
Repair as required and trace this
chart from the beginning. Press the operation switch of 4L
and go to step 5.
5 Start the engine and travel the
vehicle.
Does the speedometer run at
this time? Go to step 6. Failure of speed sensor or
disconnection or short of harness
(for the meter).
After repairing, trace this chart
from the beginning.
6 Check the harness between the
transfer controller and speed
sensor.
(Check the engine rotation
detection harness at the same
time.)
Is any trouble noticed? Failed harness between the
transfer controller and speed
sensor.
After repairing, trace this chart
from the beginning.
(Repair the engine rotation
detection unit, if required.) Go to step 7.
7 Travel the vehicle several
meters, stop it, meet the
permission requirements for
operation limits.
Did you wait for several seconds
after the requirements were
met? Failed transfer controller.
Replace the controller and trace
this chart from the beginning. You did not wait for enough time.
Optimum waiting time is 1
second or maximum 3 minutes
depending on the previous
conditions.
Refer to the paragraph about
operation without failure.
*Before determining a trouble (Non-trouble mode)

7D1-50 TRANSFER CONTROL SYSTEM
To neutral: After the correction step 5-2(*), neutral indicator blinks at 4Hz.
Check the function between H and L according to the chart for 4L to 4H instead of check
for the requirements of neutral.
Step Action Yes No
1 Is the ignition switch ON? Turn it OFF once. Go to step 2.
2 Turn ON the ignition switch and
check the valve. Do not start the
engine.
Has the valve check for 2
seconds been completed
normally? Go to step 3. Refer to the paragraph about the
indicator when it does not react
when shifted from 2H to 4H
(7D1-37).
After taking the remedy, trace
this chart from the beginning.
3 Can be shifted to 2H and then to
4L? Go to step 4.
(Impossible usually.)
Failed controller Refer to the paragraph about
shifting from 2H to 4H.
In particular, check if not at the
Check4WD condition, return to
this chart and trace it from the
beginning.
In case of Check4WD, shifting to
2H is possible.
Returning to 4H is impossible.
Refer to the paragraph about
Check4WD.
4 Set to N position in case of AT
and set to the neutral position in
case of MT and check if the lamp
blinks at 4Hz after operation. Failed T/M position switch and
harness (failure of TM1 and TM2
harness and their related
switches shown in the figure).
Incorrect wiring.
Repair as required and trace this
chart from the beginning. Shift back to 4H and go to step 5.
5 Start the engine and travel the
vehicle.
Does the speedometer run at this
time? Go to step 6. Failure of speed sensor or
disconnection or short of harness
(for the meter).
After repairing, trace this chart
from the beginning.
6 Check the harness between the
transfer controller and speed
sensor.
(Check the engine rotation
detection harness at the same
time.)
Is any trouble noticed? Failed harness between the
transfer controller and speed
sensor.
After repairing, trace this chart
from the beginning.
(Repair the engine rotation
detection unit, if required.) Go to step 7.
7 Travel the vehicle several
meters, stop it, meet the
permission requirements for
operation limits.
Did you wait for several seconds
after the requirements were met? Failed controller.
Replace the controller and trace
this chart from the beginning. You did not wait for enough time.
Optimum waiting time is 1
second or maximum 3 minutes
depending on the previous
conditions.
Refer to the paragraph about
operation without failure.
*Before determining a trouble (Non-trouble mode)
For shifting to neutral, 2H and 4L switches should be kept pressed at the same time for 10 seconds.
For shifting from neutral to other position, 2H, 4H or 4L switch should be kept pressed for 10 seconds.
When shifting from neutral to other position, the lamp blinking at 2Hz indicates active condition.
When the lamp keeps blinking at 2Hz, follow the step for the case when the lamp keeps blinking at 2Hz when
shifting between positions.

TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L) 7A2-7

TCM Voltage & Resistance Check Sheet
CHECK ITEM PIN No. VALUE NOTE
VIGN A6 –A1 VIGN
Key “ON ”

A6 –A23 VIGN
Key “ON ”
Backup Power Supply A24 –A1 +B (Always)
Key “ON ”
Inhibitor (Select) SW P B20 –A1 “P ” Range VIGN Key “ON ”

Except “P ” 0V
Inhibitor (Select) SW R B1
–A1 “R ” Range VIGN Key “ON ”

Except “R ” 0V
Inhibitor (Select) SW N B8
–A1 “N ” Range VIGN Key “ON ”

Except “N ” 0V
Inhibitor (Select) SW D B7
–A1 “D ” Range VIGN Key “ON ”

Except “D ” 0V
Inhibitor (Select) SW 2 B19
–A1 “2 ” Range VIGN Key “ON ”

Except “2 ” 0V
Inhibitor (Select)SW 1 B18
–A1 “1 ” Range VIGN Key “ON ”

Except “1 ” 0V
Inhibitor (Select) SW 3 B9
–A1 “3 ” Range VIGN Key “ON ”

Except “3 ” 0V
Power SW B13
–A1 ON 0V Key “ON ”

OFF VIGN
3rd Start SW B4
–A1 ON 0V Key “ON ”

OFF VIGN
Brake SW B22
–A1 ON VIGN Key “ON ”

OFF 0V
AT Oil Temperature
Sensor A11
–A12 20
C 4.6V Engine run.

155

C 1.1V
4L Signal B21
–A1 4L 0V Key “ON ”

2H/4H VIGN
Diag SW B12
–A1 ON VIGN Key “ON ”

OFF 0V
Shift Solenoid A (S1) A16
–A1 P VIGN Engine run.

R VIGN

N VIGN

D –1 VIGN

D –2 VIGN

D –3 0V

D –4 0V

7A2-8 TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L)

CHECK ITEM PIN No. VALUE NOTE
Shift Solenoid B (S2) A15 –A1 P 0V Engine run.

R 0V Engine run. (Without the
Reverse range lock out)
N 0V Engine run.
D –1 0V

D –2 VIGN

D –3 VIGN

D –4 0V
Lock-up Solenoid A5
–A1 ON VIGN (ex.) It is “ON ” when the
vehicle speed is more than
65km/h.
OFF 0V
Check Trans Lamp B3
–A1 ON 0V Key “ON ”
(The lamp is “ON ” for 3
second after key “ON ”)

OFF VIGN
AT Oil Temperature Lamp B11
–A1 ON 0V Key “ON ”
(The lamp is “ON ” for 3
second after key “ON ”)

OFF VIGN
Power Lamp B2
–A1 ON 0V Key “ON ”
(The lamp is “ON ” when the
Power switch is “ON ”)

OFF VIGN
3 rd Start Lamp B10
–A1 ON 0V Key “ON ”
(The lamp is “ON ” when the
3rd Start switch is “ON ”)

OFF VIGN
AT Oil Temp Sensor
Resistance A11
–A12 20

C
12k
Key “OFF ”

50

C 1.5k

155

C 293

Pressure Control Solenoid
Resistance A4
–A2 About
4 –7

(20

C)
Key “OFF ”
Speed Sensor Resistance B5 –B14 About
560

– 120
(20

C)
Key “OFF ”
Input Revolution Sensor
Resistance B6
–B16 About
560

– 120
(20

C)
Key “OFF ”
Lock-up Solenoid
Resistance A5
–A1 About
10

– 15
(20

C)
Key “OFF ”
Shift Solenoid A (S1)
Resistance A16
–A1 About
10

– 15
(20
C)
Key “OFF ”
Shift Solenoid B (S2)
Resistance A15
–A1 About
10

– 15
(20

C)
Key “OFF ”