diagram ISUZU TF SERIES 2004 Workshop Manual

7A2-120 DIAGNOSIS (JR405E)
No. D2: Gear is Shifted Frequently

Description:

Gear is shifted down immediately though the accelerator pedal is stepped on a little in D, 3, 2, or L range.

Diagnosis Hints:

Basically, the same cause as "No. D1: Faulty gear shifting" is considered. However, as possible cause, fault
input signal of throttle position sensor or speed sensor, fault input signal of inhibitor switch, or fault of TCM
power source, earth, ground return wire are considered first.

Then, slip of the clutch, fault of the control valve are considered.





No. D3: Gear Shift Point is Low or High at All Point
No. D4: Gear Shift Point is Low or High at Limited Point

Description:

Gear shift point is deviated from the shift diagram.

Gear is not shifted up properly though the vehicle is accelerated.

Gear is not shifted immediately and enough acceleration cannot be obtained though the accelerator pedal is
stepped on.

Diagnosis Hints:

If the cause is not faulty gear shift, throttle position sensor disordered or fault input of speed sensor is
considered. Output signal of the throttle position sensor is changed to linear one.
(Refer the paragraph about the faulty throttle position sensor of "No. D1: Faulty gear shifting".)





No. D5: No Kick-down

Description:

The engine speeds up but vehicle speed does not increase when the accelerator pedal is stepped on at the
starting.

Diagnosis Hints:

When the gear shift is normal only without kick-down, possibility of fault of the throttle position sensor. Check
that the throttle voltage increases linearly in proportion to the throttle opening.
(Refer the paragraph about the faulty throttle position sensor of "No. D1: Faulty gear shifting".)

7A2-144 DIAGNOSIS (JR405E)
TEST DRIVE




NOTE:
Perform the test at normal operation ATF temperature 50 -
80




C.
Drive the vehicle on level ground so as not to change to
up and down hill control.

1. D range test in Normal and Power shift pattern.
1) Shift into the D range and hold the accelerator pedal
constant at the 50% and 100% throttle angle.
2) 1-2, 2-3, 3-4 and lock-up, up-shift should take place, and
shift points should confirm to those shown in the
diagram.
3) Also check to see that downshift is made from 4-3, 3-2
and 2-1 down-shift point is within the limits shown in the
diagram.
2. 3 range test in Normal and Power shift pattern.
1) Shift into the 3 range and hold the accelerator pedal
constant at the 50% and 100% throttle angle.
2) 1-2, 2-3 and lock-up, up-shift should take place, and
shift points should confirm to those shown in the
diagram.
3) While running in the 3 rages, does not up-shift 3-4.
4) Also check to see that down-shift is made from 4-3, 3-2
and 2-1 down-shift point is within the limits shown in the
diagram.
3. 2 range test in Normal shift pattern.
1) Shift into the 2 range and hold the accelerator pedal
constant at the 50% and 100% throttle angle.
2) 1-2 and up-shift should take place, and shift points
should confirm to those shown in the diagram.
3) While running in the 2 rages, does not up-shift 2-3 or 3-
4, and lock-up does not operate.
4) Also check to see that down-shift is made from 4-3, 3-2
and 2-1 down-shift point is within the limits shown in the
diagram.


4. L range test in Normal shift pattern.
1) While running in the L rages, does not up-shift 1-2, 2-3
or 3-4, and lock-up does not operate.
2) Also check to see that down-shift is made from 4-3, 3-2
and 2-1 down-shift point is within the limits shown in the
diagram.

DIAGNOSIS (JR405E) 7A2-149
SHIFT POINT DIAGRAM