2004 ISUZU TF SERIES low oil pressure
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7A2-106 DIAGNOSIS (JR405E)
No. B6: Engine Starter Does Not Run in P or N Range
No. B7: Engine Starter Runs Except in P or N Range
Description:
The engine starter does not run though the P or N range is selected.
The engine starter runs though the R or D, 3, 2or L range is selected.
Possible Cause:
Disordered select cable.
Disordered Inhibitor switch, disconnection or short-circuit of inhibitor switch.
No. B8: Extended Time Lag When Shift Lever is Changed to N to D
Description:
The shift time lag is longer than standard value when shift lever is changed to N to D.
Possible Cause:
Forward range line pressure is low.
Slip of low & reverse 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.
No. B9: Extended Time Lag When Shift Lever is Changed to N to R
Description:
The shift time lag is longer than standard value when shift lever is changed to N to R.
Possible Cause:
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.
Page 4099 of 4264
DIAGNOSIS (JR405E) 7A2-107
No. B10: Brake is Applied in R Range
Description:
Brake is applied suddenly in R range.
Diagnosis Hints:
Basically a trouble in the AT main unit. However, some trouble in the sensor system or output system may have
some influence on the trouble in the main unit and therefore these systems should be also checked to prevent
reproduce of the trouble.
Possible Cause:
Seized clutch (low clutch, high clutch, 2-4 brake).
Shortage or faulty quality of ATF.
Trouble in control valve body (faulty operation, sticking, clogged oil passage).
Disordered select cable (select indicator light indicates R but the hydraulic system is not in the R range).
Malfunction of parking mechanism.
No. B11: Insufficient Starting or Shaking in D Range
Description:
Insufficient starting or shaking in D range.
Possible Cause:
Slip of clutch (low clutch, low one-way clutch, reverse clutch, low & reverse brake).
If slip of clutch is caused, a DTC (gear ratio error) is stored.
Shortage or faulty quality of ATF.
Dropped line pressure.
Trouble in control valve body (faulty operation, sticking, clogged oil passage).
No. B12: Noise or Vibration is Generated at Starting
Description:
Noise or vibration is generated in the vicinity of AT at starting.
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.
Page 4113 of 4264
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.
Page 4124 of 4264
7A2-132 DIAGNOSIS (JR405E)
No. G3: Creep Force is small
Description:
Vehicle does not move though a run range is selected on a flat road during the idling.
Diagnosis Hints:
When the creep force is small in all ranges, low engine output is considered. Another possible cause is slip of
clutch. If the creep is normal only in the R range, operation of the fail-safe function due to a trouble in the electrical
system is considered.
Possible Cause:
Slip of clutch (low clutch).
If slip of clutch is caused, a DTC (gear ratio error) is stored.
Low engine output (low idling speed, out of injection timing, lowered compression pressure, etc.).
Shortage or faulty quality of ATF.
Disconnection or short circuit of solenoid valve output.
Clogged oil passage of solenoid valve output.
Faulty ground return line in AT assembly.
If the ground return line earth is faulty, clutch pressure may decrease causing slip of the clutch.
Trouble in the torque converter system (faulty operation).
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.
4 Are the idling speed and other engine system normal?
Go to Step 5
Repair the defect or
replace.
5 Is the stall revolution normal in D, 3, 2 and L range? Refer
the STALL TEST section in this manual.
Go to Step 6
Repair the defect or
replace.
6 Is the line pressure normal? Refer the LINE PRESSURE
TEST section in this manual. Trouble in the AT
assembly or control
valve.
Repair the defect or
replace.
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 4131 of 4264
DIAGNOSIS (JR405E) 7A2-139
No. Z11: Abnormal Oil Pressure
Description:
Oil pressure is low or high.
Possible Cause:
Basically, the same cause as "No. C1 - C8: Engine races up (slip) by shift up or shift down" is considered.
In case of oil pressure is low, faulty oil pump is considered.
No. Z12: Reverse Buzzer Does Not Ring
Description:
Reverse buzzer does not ring in R range.
Possible Cause:
Disordered select cable.
Disordered select lever.
Disordered inhibitor switch.
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.