brake ISUZU TF SERIES 2004 Workshop Manual

7A2-116 DIAGNOSIS (JR405E)
When signal from the speed sensor becomes out of order, it may be judged a result of changed vehicle
speed and faulty gear shifting may be the causes.







Trouble in control valve body (faulty operation, sticking, clogged oil passage)



Step Action Yes No
1 Dislocation or disordered of select lever.
Does the vehicle move when the brake is released in a position
other than the P range and the vehicle is pushed?
Go to Step 2
Adjust the select
cable.
2 Gear ratio trouble diagnosis.
Travel in the following sequence for about 7 seconds or more in
each range: Start in the L range (1st) to 2 range (2nd) to 3 range
(3rd) to D range (4th) (to detect the gear ratio trouble exactly, this
process should be carried out)
Go to Step 3 Go to Step 3
3 Are any DTCs stored?
Go to DTC Chart Go to Step 4
4 Are the quantity, contamination and smell normal?

If the ATF level is
low, replenish up to
the specified level.

Go to Step 5
If ATF is extremely
black and
contaminated and
smells burnt, slip of
the clutch is
supposed.

DIAGNOSIS (JR405E) 7A2-117
Step Action Yes No
5 Inspection of electrical or mechanical fault
Is signal to each solenoid and pressure switch changed
synchronously to the faulty gear shift?

Control Valve


TCM


B1





B12





B20 RED/YEL
WHT/BLK 2-4 Brake Pressure SW

Terminal
Assembly
YEL
E54

(7)





(12)





(1) H23

(12)





(10)C95

(1)





(12)





(20) RED/YEL
YEL
WHT/BLK
L&R Brake Pressure SW

High Clutch Pressure SW

H22

(8)
Control Valve

TCM
B6
B7
B8
B9
B22 (GND) BLU/BLK
WHT/BLU L&R Brake Solen oid

Te r m i n a l
Assembly
BLK/YEL
RED
2-4 Brake Solenoid

High Clutch Solenoid

Low Clu tch S olen oid

E54
(5)
(9)
(10)
(3)
(11)H23
(11)
(5)
(7)
(2)
(1)
GRY/REDC95
(6)
(7)
(8)
(9)
(22) BLU/BLK
BLK/YEL
RED
WHT/BLU
GRY/RED
Range TCM terminal
GearB20
(High clutch
pressure SW)B1
(2-4 brake pressure
SW)B12 (Low & reverse
brake pressure SW)P - More than 10V More than 10V More than 10VR Reverse More than 10V More than 10V -N - More than 10V More than 10V More than 10VD, 3, 2 1st More than 10V More than 10V More than 10V2nd More than 10V - More than 10V3rd - More than 10V More than 10V4th - - More than 10VL 1st More than 10V More than 10V -2nd More than 10V - More than 10V3rd - More than 10V More than 10V4th - - More than 10V
Range TCM terminal
GearB8
(High clutch
solenoid)B9
(Low clutch
solenoid)B7
(2 -4 b rake
solenoid)B6
(Lo w & reve rs e
brake solenoid)P - Approx. 6.8V
(AC range)- Approx. 6.8V
(AC range)Approx. 6.2V
(AC ra ng e)
R Reverse Approx. 6.8V
(AC range)- Approx. 6.8V
(AC range)-
N - Approx. 6.8V
(AC range)- Approx. 6.8V
(AC range)Approx. 6.8V
(AC ra ng e)
D, 3, 2 1st Approx. 6.8V
(AC range)- Approx. 6.8V
(AC range)Approx. 6.8V
(AC ra ng e)
2nd Approx. 6.8V
(AC range)- - Approx. 6.8V
(AC ra ng e)
3rd - - Approx. 6.8V
(AC range)Approx. 6.8V
(AC ra ng e)
4th - Approx. 6.8V
(AC range)- Approx. 6.8V
(AC ra ng e)
L 1st Approx. 6.8V
(AC range)- Approx. 6.8V
(AC range)-
2nd Approx. 6.8V
(AC range)- - Approx. 6.8V
(AC ra ng e)
3rd - - Approx. 6.8V
(AC range)Approx. 6.8V
(AC ra ng e)
4th - Approx. 6.8V
(AC range)- Approx. 6.8V
(AC ra ng e)
Go to Step 6
In case of fault in
the machine
system, repair that
portion or replace
the unit.
Slip of clutch or fault
of control valve.

DIAGNOSIS (JR405E) 7A2-121
No. E1: No Gear Shift

Description:

Range is fixed without shifting the gear of 1st to 2nd, 2nd to 3rd, and 3rd to 4th.

Gear may be shifted or may not be shifted.

Diagnosis Hints:

Fixing at some gear speed, signal error from throttle position sensor or trouble in the AT main unit are supposed.

Possible Cause:

Slip of clutch (low clutch, high clutch and 2-4 brake).
If slip of clutch is caused, a DTC (gear ratio error) is stored.

Dropped line pressure.

Fixing at 3rd position (fail-safe activated).
Since the gear is fixed at the 3rd position because of the fail-safe function, a trouble that "No gear shift"
is resulted. In this case, the DTC is memorized.
When TCM stops operation because of faulty TCM ground, the gear is fixed at the 3rd position because
of a mechanical reason. In this case, no DTC is memorized.





Incorrect properties of throttle opening signal (serial communication) of throttle position sensor.
Throttle opening signal (serial communication) of the throttle position sensor does not change in
proportion to the throttle opening. In this case, fixing at the high or low gear results in such a trouble
that "No Gear Shift".

Trouble in control valve body (faulty operation, sticking, clogged oil passage)

Step Action Yes No
1 Gear ratio trouble diagnosis.
Travel in the following sequence for about 7 seconds or more in
each range: Start in the L range (1st) to 2 range (2nd) to 3 range
(3rd) to D range (4th) (to detect the gear ratio trouble exactly, this
process should be carried out).
Go to Step 2 Go to Step 2
2 Are any DTCs stored?
Go to DTC Chart Go to Step 3
3 Are the quantity, contamination and smell normal?
If the ATF level is
low, replenish up to
the specified level.

Go to Step 4
If ATF is extremely
black and
contaminated and
smells burnt, slip of
the clutch is
supposed.
Overhaul the AT
unit.

7A2-124 DIAGNOSIS (JR405E)
No. E2: Only 4th gear (O/D) is Not Selectable

Description:

Gear is not shifted up from 3rd to 4th though the vehicle is accelerated.

Possible Cause:

Disordered select cable.

Disordered inhibitor switch.

ATF thermo sensor detects low oil temperature (4th gear is prohibited temperature less than 10C.).

Clogged oil passage of low clutch duty solenoid.

Trouble in control valve body (faulty operation, sticking, clogged oil passage).

Step Action Yes No
1 Dislocation or disordered of select lever.
Does the vehicle move when the brake is released in a position
other than the P range and the vehicle is pushed?
Go to Step 2
Adjust the select
cable.
2 Gear ratio trouble diagnosis.
Travel in the following sequence for about 7 seconds or more in
each range: Start in the L range (1st) to 2 range (2nd) to 3 range
(3rd) to D range (4th) (to detect the gear ratio trouble exactly, this
process should be carried out)
Go to Step 3 Go to Step 3
3 Are any DTCs stored?
Go to DTC Chart Go to Step 4
4 Are the quantity, contamination and smell normal?
If the ATF level is
low, replenish up to
the specified level.

Go to Step 5
If ATF is extremely
black and
contaminated and
smells burnt, slip of
the clutch is
supposed.
Overhaul the AT
unit.

7A2-130 DIAGNOSIS (JR405E)
No. F2: Engine Races Up During Acceleration (Slip)

Description:

The engine speed up when the accelerator pedal is stepped on for acceleration and the gear is shifted up or
down.

Only the engine speeds up but vehicle speed does not increase when the accelerator pedal is stepped on for
acceleration during the running.

Diagnosis Hints:

Basically same causes as "No. C1 - C8: Engine races up (slip) by shift up or shift down" are considered.
When the condition of No. C1-C8 grows worse, symptom of No. F2 results.




No. F3: Noise or Vibration During the Running in R, D, 3, 2 or L Range

Description:

Noise or vibration is generated in the vicinity of AT during the running.

Diagnosis Hints:

Cause other than AT can be also considered. It is effective means to reproduce a running condition using a lift
up, chassis dynamo, etc. to investigate the origin (generating condition) of noise and vibration.
Caution:
Lifting up some unit to test it accompanies danger. Provide safety measures as far as possible and
carry out the test with sufficient care.

Possible Cause:
Following sources of noise or vibration other than the AT can be considered.

Noise from differential gears.

Noise from propeller shaft.

The bearing support in the middle of the propeller shaft has fatigued, and the bend angle of the propeller shaft
has changed, causing vibration at the time of start.

Unbalanced and poor uniformity of tires cause vibration.




No. F4: Engine Brake Does Not Apply in L Range

Description:

The engine brake does not apply, allowing the vehicle to run freely when the accelerator pedal is released at low
speed in L range.

Possible Cause:

Slip of clutch (low & reverse brake)
If slip of clutch is caused, a DTC (gear ratio error) is stored.

Faulty input/output signal system.
Low & reverse brake duty solenoid

Faulty control valve (faulty operation, sticking).

DIAGNOSIS (JR405E) 7A2-131
No. F5: Engine Stalls Before Vehicle Stops from Running

Description:

The engine stalls simultaneously with the vehicle stop when the brake pedal is stepped on to stop the vehicle
during the running.

Possible Cause:

Trouble on the engine system side (fuel injection control, engine speed control, etc.) is considered.

Refer to "No. B5: Engine stalls when selecting from N range to R, D, 3, 2 or L range".





No. G1: Vehicle Moves in P Range or Parking Gear is Not
Disengaged other than P Range

Description:

Vehicle moves though it stops at a slope and P range is selected.

The engine stalls and vehicle does not move though other than P range is selected and the accelerator pedal is
stepped on.

Possible Cause:

Trouble of the parking mechanism (noise or shock may result).

Disordered selector cable (only when traveling in the P range).

If the vehicle moves in the N range, follow the procedure of "No. B1: Vehicle runs in N range".





No. G2: Creep Force is Large

Description:

Vehicle accelerates in D, 3, 2, L, and R ranges though the accelerator pedal is not stepped on.

Possible Cause:

Too high engine idling speed (not attributable to AT).

7A2-140 DIAGNOSIS (JR405E)
STALL TEST
CAUTION:
Because A/T may break down, do not perform the stall test continuously.

Procedure
1. Chock the four wheels.
2. Warm up the engine.
3. Apply the parking brake.
4. Step on the foot brake fully.
5. Set the select lever to either D, 3, 2, L or R range.
6. Step on the accelerator pedal fully.
7. When the engine speed becomes constant, record tha
t
value quickly.

Stall Speed
Standard: 2600±150 rpm

Evaluation
1. If the stall speed is higher than standard value in all
ranges.

Low line pressure.

Abraded oil pump.

Faulty operation of low clutch.

Adjustment error of or faulty inhibitor switch.


ATF leaking from oil pump, control valve, or
transmission case.

Fixed pressure regulator valve and pilot valve.
2. If the stall speed is higher than standard value in D, 3, 2
and L ranges.

Slip of low clutch.

Slip of low one-way clutch.
3. If the stall speed is higher than standard value in
R
range.

Slip of low & reverse brake.

Slip of reverse clutch.
4. If the stall speed is lower than standard value in all
ranges.

Slip of one-way clutch (in torque converter).

Faulty engine.

DIAGNOSIS (JR405E) 7A2-141
LINE PRESSURE TEST
Procedure
1. Chock the four wheels.
2. Remove the test plug of the transmission case and fit the oil
pressure gauge.
3. Warm up the engine.
4. Apply the parking brake.
5. Step on the foot brake fully.
6.Set the select lever to either D, 3, 2, L or R range.
7. Record the oil pressure at idling.
8. When stepping over the accelerator pedal fully and the
engine speed becomes constant, record the oil pressure
quickly.

Line Pressure
Standard:
Engine Line Pressure (Kpa)
Speed D, 3, 2 or L Range R Range
Idling 350 - 480 450 - 650
Stall 1,050 - 1,250 1.400 - 1,630

Evaluation
1. If the line pressure is lower than standard value at
idling in all ranges.

Abraded oil pump.

Faulty operation of each solenoid.

Sticking of pressure regulator valve or pilot valve.

Fatigued pressure regulator valve or pilot valve spring.


ATF leaking from oil strainer, oil pump, pressure
regulator valve, torque converter relief valve or pressure
relief valve.
2. If the line pressure is lower than standard value at
idling in D, 3, 2 and L ranges.

ATF leaking from low clutch hydraulic circuit.
3. If the line pressure is lower than standard value at
idling in R range.

ATF leaking from reverse hydraulic circuit.

ATF leaking from low and reverse brake hydraulic
circuit.

7A2-142 DIAGNOSIS (JR405E)
1. Oil Cooler Out
2. R Range Line Pressure Detection Port
(Low & Reverse Brake Pressure Detection Port)
3. D, 3, 2 & L Range Line Pressure Detection Port
(Low Clutch Pressure Detection Port)
4. Oil Cooler In

4. If the line pressure is lower than standard value at
idling in L and R ranges.


ATF leaking from low and reverse brake hydraulic
circuit.
5. If the line pressure is higher than standard value at
idling in all ranges.

Throttle opening signal reception error.

Faulty oil temperature sensor.

Faulty operation of low clutch solenoid.

Sticking pilot valve.

Sticking pressure regulator valve or plug.
6. If the line pressure is lower than standard value at stall
speed in all ranges.

Throttle opening signal reception error.

Faulty operation of line pressure solenoid.

Faulty operation of low clutch solenoid.

Sticking pilot valve.

Sticking pressure regulator valve or plug.

DIAGNOSIS (JR405E) 7A2-143
TIME LAG TEST
Procedure
1. Chock the four wheels.
2. Warm up the engine.
3. Apply the parking brake.
4. Step on the foot brake fully.
5. Set the select lever from N to D or N to R range.
6. Record the time from when moving the select button until
feeling shock.

Time Lag
Standard:
N to D Range: Below 0.7 Seconds
N to R Range: Below 1.2 Seconds

Evaluation
1. If the time lag is out of standard value when shifting N
to D range.

Forward range line pressure is low.

Slip of low clutch.

Slip of low one-way clutch.

Trouble in control valve body (faulty operation, sticking,
clogged oil passage).

Faulty low clutch duty solenoid operation.

Shortage or faulty quality of ATF.
2. If the time lag is out of standard value when shifting N
to R range.

Reverse range line pressure is low.

Slip of low & reverse brake.

Slip of reverse clutch.

Trouble in control valve body (faulty operation, sticking,
clogged oil passage).

Faulty low & reverse brake duty solenoid operation.

Shortage or faulty quality of ATF.