2004 ISUZU TF SERIES Transmission
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DIAGNOSIS (JR405E) 7A2-91
SYMPTOM DIAGNOSIS
Symptom Condition Description
Oil Leak Breather Oil leaks from breather. J1
Between engine and converter housing Oil leaks between engine and converter
housing. J2
Between converter housing and main caseOil leaks between converter housing and
main case. J3
Between main case and rear housing Oil leaks between main case and rear
housing. J4
Oil pan Oil leaks from oil pan. J5
Manual shaft oil seal Oil leaks from manual shaft oil seal. J6
Oil cooler pipe Oil leaks from oil cooler pipe joint. J7
Other Transmission overheat You smell the transmission burning. Z1
The transmission smokes.
Mode lamp does not light up when the
power mode or 3rd start mode is turned on
The mode lamp on the instrument panel
does not light up though the power mode or
3rd start mode is turned on with the ignition
switch in ON position.
Z2
Mode lamp lights up when the power mode
or 3rd start mode is turned off
The mode lamp on the instrument panel
lights up though the power mode or 3rd start
mode is turned off with the ignition switch in
ON position.
Z3
Oil temperature warning lamp lights up Sometimes, the oil temperature warning
lamp lights up. Z4
Select lever feeling is faulty Select lever feeling is faulty. Z5
Poor fuel consumption Poor fuel consumption. Z6
Pattern select switch is faulty Shift pattern does not change though the
pattern select switch is turned on. Z7
Oil is splashed during the running Oil is splashed during the running. Z8
Abnormal smell Abnormal smell. Z9
Oil quantity is low or high Oil quantity is low or high. Z10
Abnormal oil pressure Oil pressure is low or high. Z11
Reverse buzzer does not ring Reverse buzzer does not ring in R range. Z12
Page 4125 of 4264
DIAGNOSIS (JR405E) 7A2-133
No. G4: Large Noise During Idling with the Vehicle in Stop State
Description:
The transmission is noisy during the idling speed in all ranges.
Diagnosis Hints:
Causes such as solenoid operating sound or faulty oil pump are considered.
Distinguishing to some extent is possible by stopping the solenoid operation temporarily, checking the correlation
for the former case and, changing the line pressure and confirming the correlation with noise.
As a matter of course, noise may be generated around the engine, for instance, other than the AT and should be
checked carefully.
Note:
When the noise is generated only at the time of gear shift, it may be the sound of flowing ATF or gear
noise. If the sound varies depending on the gear speed to be shifted, it may be the gear noise generated
from the planetary gear and its related components. If the sound varies depending on the vehicle
speed, it may be the gear noise of the output system, and if varying depending on the engine speed, it
may be the gear noise of the input system or faulty torque converter.
In either case, sound may be "noise" depending on the origin and resonance object. When the object
generating the sound (resonance object) and the sound source (vibration source) are different,
investigation of the cause may be difficult.
No. H1: Judder Occurs at the Lock-up
Diagnosis Hints:
The vehicle body judders at lock-up.
Diagnosis Hints:
Slip due to burning of the lockup piston or insufficient fastening due to dropped working pressure are considered.
Trouble diagnosis flow is basically the same as "No. I1: No lock-up".
Note:
When the lock-up piston has burnt, foreign material mixed in the oil cooler is considered. In such a
case, inspect the oil cooler circuit for clogging of the oil cooler.
No. H2: Large Lock-up Shock
No. H3: Lock-up Point is High or Low
Description:
Large shock is felt at lock-up.
Lock-up point is excessive high or low.
Diagnosis Hints:
Out of properties of input sensor or faulty lock-up piston pressure system are considered.
Trouble diagnosis flow is basically the same as "No. I1: No lock-up".
Page 4128 of 4264
7A2-136 DIAGNOSIS (JR405E)
No. J1: Oil Leaks from Breather
Description:
Oil leaks from breather.
Possible Cause:
ATF quantity is excessively.
No. J2: Oil Leaks Between Engine and Converter Housing
No. J3: Oil Leaks Between Main Case and Converter Housing
No. J4: Oil Leaks Between Main Case and Rear Housing
No. J5: Oil Leaks from Oil Pan
No. J6: Oil Leaks from Manual Shaft Oil Seal
No. J7: Oil Leaks from Oil Cooler Pipe Joint
Description:
Oil leaks between engine and converter housing.
Oil leaks between converter housing and main case.
Oil leaks between main case and rear housing.
Oil leaks from oil pan.
Oil leaks from manual shaft oil seal.
Oil leaks from oil cooler pipe joint.
Possible Cause:
Faulty oil seal or sealing of contact surface is considered.
No. Z1: Transmission Overheat
Description:
You smell the transmission burning.
The transmission smokes.
Possible Cause:
Slip of clutch.
If slip of clutch is caused, a DTC (gear ratio error) is stored.
Clogged oil cooler (foreign substance mixed)
ATF stirred excessively (too much ATF).
Faulty torque converter operating pressure.
Faulty lock-up piston.
Page 4129 of 4264
DIAGNOSIS (JR405E) 7A2-137
No. Z2: Mode Lamp (Power Drive or 3rd Start) Does Not Light Up
When The Power Mode or 3rd Start Mode is Turned On
Description:
The mode lamp on the instrument panel does not light up though the power mode or 3rd start mode is turned on
with the ignition switch in ON position.
Possible Cause:
Faulty mode select switch is considered.
Bulb burn out.
No. Z3: Mode Lamp (Power Drive or 3rd Start) Lights Up When
The Power Mode or 3rd Start Mode is Turned Off
Description:
The mode lamp on the instrument panel lights up though the power mode or 3rd start mode is turned off with the
ignition switch in ON position.
Possible Cause:
Faulty mode select switch is considered.
No. Z4: Oil Temperature Warning Lamp Lights up
Description:
Sometimes, the oil temperature warning lamp lights up.
Possible Cause:
When the vehicle is stuck in the mud or continues to accelerate under overload, and ATF temperature exceeds
145 C, the oil temperature warning lamp lights up.
If the oil temperature warning lamp lights up under usual service condition, following causes are considered.
ATF level has increased for some fault.
Refer to "No. Z1: Transmission overheat".
Lights up due to error of the ATF oil thermo sensor.
No. Z5: Select Lever Feeling is Faulty.
Description:
Select lever feeling is faulty.
Possible Cause:
Disordered select cable.
Disordered select lever.
Faulty Manual plate.
Page 4132 of 4264
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.
Page 4133 of 4264
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.
Page 4137 of 4264
DIAGNOSIS (JR405E) 7A2-145
5. R range test.
1) Shift into the R range and while starting at full throttle,
check for slipping.
6.P range test.
1) Stop the vehicle on a grade and after shifting into the P
range, release the parking brake. Then check to see tha
t
the parking lock pawl holds the vehicle in place.
Select
Lever
Position
Gear
Position
Gear
Shift
P
R Reverse
N
D 1st
2nd
3rd
4th
3 1st
2nd
3rd
4th(*1)
2 1st
2nd
3rd(*1)
4th(*1)
L 1st
2nd(*1)
3rd(*1)
4th(*1)
Evaluation
1. If there is no 1 to 2 up-shift.
2-4 brake malfunction.
2-4 brake hydraulic circuit failed.
2-4 brake duty solenoid stick.
Refer to symptom diagnosis "No. D1: Faulty Gea
r
Shifting" or DTC section "Gear Ratio Error".
2. If there is no 2 to 3 up-shift.
High clutch malfunction.
High clutch hydraulic circuit failed.
High clutch duty solenoid stick.
Refer to symptom diagnosis "No. D1: Faulty Gea
r
Shifting" or DTC section "Gear Ratio Error".
3. If there is no 2 to 4 (O/D) up-shift.
2-4 brake malfunction.
2-4 brake hydraulic circuit failed.
2-4 brake duty solenoid stick.
Refer to symptom diagnosis "No. D1: Faulty Gea
r
Shifting" or DTC section "Gear Ratio Error".
4. If there is no lock-up in 2, 3 and 4.
Lock-up piston malfunction.
Lock-up hydraulic circuit failed.
Lock-up duty solenoid stick.
Refer to symptom diagnosis "No. I1: No Lock-up"o
r
DTC section "Lock-up Duty Solenoid Failure".
*1: Transmission is shifted at high speed to
prevent engine over-run.
Page 4146 of 4264
7A2-154 DIAGNOSIS (JR405E)
TCM VOLTAGE CHECK
TCM voltage check is done to check for transmission and TCM
problems which cannot be detected by self-diagnosis.
Additionally, it severs as a back-up check for self-diagnosis.
Measure the voltage drop and make a continuity test for each of
sensors, solenoids and switches.
If the voltage is within the specified range and continuity exists,
that particular area of the TCM and transmission assembly is
normal.
If voltage deviation or lack of continuity is discovered, disconnect
the applicable parts and check of them individually.
Inspection Tool
Use a circuit tester and an oscilloscope to measure voltage and
circuit continuity.
Insert the test probes from the connector wiring side. TCM
terminals are extremely small.
Wrap a piece of thin wire around the probe of tester.
This will make measurement easier.
TCM Pin Assignment
Connect to White Connector Connect to Grey Connector
No. Wire
Color Pin Name Input /
OutputConnected toMeasurement
Item Measurement
Condition StandardInspection
Point at
Trouble
A1 RED V BATT (Battery Back-up Power
Supply) Input Battery Voltage - 10 – 14.5V Related
harness
At P range 10 – 14.5V Related
harness
A2 YEL/
VIO P Range Switch Input Inhibitor switch Voltage
At other than
P range Less than 2VInhibitor
switch
At brake
stepped 10 – 14.5V Related
harness
A3 RED Brake Switch Input Brake switch Voltage At brake no
stepped Less than 2V Brake switch
At lamp OFF 10 – 14.5V Related
harness A4 PNK/
WHT 3rd Start Indicator Lamp Output 3rd start lamp Voltage
At lamp ON Less than 2V Lamp
A5 GRN K-line signal (Tech 2 serial
communication) Input/
OutputTech 2 - - - Related
harness
A6 - - - - - - - -