transmission fluid ISUZU KB P190 2007 Workshop Repair Manual

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-111
D2: Gearshift Frequently
Diagnosis Hints• When inspecting faulty gear shifting, it is important to distinguish between
the fault of the electric system and transmission main unit.
• Fault of electric system. - Monitor the output signal (each solenoid driving signal) using a scan tool. If a trouble signal is sent to the solenoid synchronously with the faulty
gear shifting, the fault is originated in the electric system.
- Monitor the input signal (signal from each sensor) using a scan tool and find an input signal which has an output signal (each solenoid driving
signal) subjected to a fault.
- Fault of the electric system may be derived from temperature or vibration. For instance, although the engine is normal while it is cold, fault may
occur when the engine is warmed up or the vehicle is running.
• Fault of mechanical system. - If the gear is incorrectly shifted, irrespective of the operating signal (On/ Off) of each solenoid, the fault is originated from the transmission main
unit.
- If the clutch slips, or the transmission fluid smells burnt or is contaminated or black, or the stall speed increases. Gear ratio error DTC might be set.
Transmission Range Switch & Selector
Lever Cable Checks Inspect the transmission range switch and selector lever cable for misadjusting
or disordering. Refer to On-Vehicle Service section.
Transmission Fluid Checks Inspect the transmission fluid for the following conditions. If the transmission fluid
is extremely blacked, contaminated or smells burnt, slipping of clutch is
suspected.
• Low quantity
• Contamination
•Smell
Line Pressure Checks Inspect the line pressure in forward ranges for a possible dropped pressure.
Refer to Line Pressure Test in Test Instruction section.
Stall Speed Checks Inspect the stall speed in forward ranges. Refer to Stall Test in Test Instruction
section.
Control Valve Body Checks Inspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Sticking shift solenoid valve. Perform function check. Refer to On-Vehicle Service section.
• Faulty operation of transmission fluid pressure switch. Perform function check. Refer to On-Vehicle Service section.
• Clogged hydraulic circuit
Checks
Action
Checks Action
Definition:
Shift down or engine overrun occurs above than kick-down area.
Diagnosis Hints The same causes as in category No. “C1 - C8: Engine Race Up (Slipping)” are
suspected.

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ISUZU KB P190 2007

7A2-112 TRANSMISSION CONTROL SYSTEM (JR405E)
D3: Gearshift Point is Low or High at All Points
D4: Gearshift Point is Low or High at Limited Area
D5: No Kick-down
E1: No Gearshift
Checks Action
Definition: • Gearshift point is deviated from the shift speed chart.
• Gear is not shifted up properly, even though the vehicle is accelerating.
• Gear is not shifted immediately and enough acceleration cannot be obtained, even though the accelerator pedal is being stepped on.
Diagnosis Hints • Inspect the output shaft speed (OSS) sensor for faulty operation.
• Incorrect accelerator pedal position signal is suspected. Observe the Accelerator Pedal Position (APP). APP parameter should change linearly
from 0 to 99 or 100% according to the accelerator pedal operation.
Checks Action
Definition:
The engine speeds up but the vehicle speed does not increase when the accelerator pedal is being stepped on at starting.
Diagnosis Hints Incorrect accelerator pedal position signal is suspected. Observe the
Accelerator Pedal Position (APP). APP parameter should change linearly from
0 to 99 or 100% according to the accelerator pedal operation.
Checks Action
Definition: • Gear is fixed, such as no gearshift from 1st to 2nd, 2nd to 3rd, and 3rd to 4th.
• Sometimes the gear is shifted, and sometimes it is not possible.
Diagnosis Hints • Fixing at same gear speed, a signal error from the accelerator pedal
position (APP) sensor or trouble in the transmission main unit are
suspected.
• Slipping of the clutch is suspected. Gear ratio error DTC might be set.
Transmission Range Switch & Selector Lever
Cable Checks Inspect the transmission range switch and selector lever cable for misadjusting
or disordering. Refer to On-Vehicle Service section.
Transmission Fluid Checks Inspect the transmission fluid for the following conditions. If the transmission
fluid is extremely blacked, contaminated or smells burnt, slipping of clutch is
suspected.
• Low quantity
• Contamination
•Smell
Line Pressure Checks Inspect the line pressure in forward ranges for a possible dropped pressure.
Refer to Line Pressure Test in Test Instruction section.
Stall Speed Checks Inspect the stall speed in forward ranges. Refer to Stall Test in Test Instruction
section.
Control Valve Body Checks Inspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Sticking shift solenoid valve. Perform function check. Refer to On-Vehicle Service section.
• Clogged hydraulic circuit
Clutch and Brake Checks Inspect the low clutch, high clutch or low & reverse brake for slipping.

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-113
E2: Only 4th Gear is Not Selectable
E3: Gear is Changed from 2nd to 3rd in 2 Range
E4: Gear is Changed from 1st to 2nd in L Range
E5: Gear is Changed from 3rd to 4th in 3 Range
Sensor Checks Inspect the input shaft speed (ISS) sensor and output shaft speed (OSS)
sensor for faulty operation.
Additional Checks • Inspect the TCM grounds for being clean, tight, and in their proper
locations.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 99 or 100% according to the accelerator pedal
operation.
Checks
Action
Checks Action
Definition:
Gearshift is not possible from 3rd to 4th even though the vehicle is accelerating.
Diagnosis Hints When the transmission fluid temperature is lower than 10 °C (50 °F), gearshift
from the 3rd to the 4th is inhibited.
Transmission Range Switch & Selector Lever
Cable Checks Inspect the transmission range switch and selector lever cable for misadjusting
or disordering. Refer to On-Vehicle Service section.
Transmission Fluid Checks Inspect the transmission fluid for the following conditions. If the transmission
fluid is extremely blacked, contaminated or smells burnt, slipping of clutch is
suspected.
• Low quantity
• Contamination
•Smell
Line Pressure Checks Inspect the line pressure in forward ranges for a possible dropped pressure.
Refer to Line Pressure Test in Test Instruction section.
Stall Speed Checks Inspect the stall speed in forward ranges. Refer to Stall Test in Test Instruction
section.
Control Valve Body Checks Inspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Sticking shift solenoid valve. Perform function check. Refer to On-Vehicle Service section.
• Clogged hydraulic circuit
Clutch and Brake Checks Inspect the low clutch for seizing.
Sensor Checks Inspect the transmission fluid temperature (TFT) sensor. Use the Temperature
vs. Resistance table to test the TFT sensor at various temperature levels to
evaluate the possibility of a skewed sensor.
Checks Action
Definition: • Gear is shifted from 2nd to 3rd in 2 range.
• Gear is shifted from 1st to 2nd in L range.
• Gear is shifted from 3rd to 4th in 3 range.
Transmission Range Switch & Selector Lever
Cable Checks Inspect the transmission range switch and selector lever cable for misadjusting
or disordering. Refer to On-Vehicle Service section.

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ISUZU KB P190 2007

7A2-114 TRANSMISSION CONTROL SYSTEM (JR405E)
F1: Low Maximum Speed or Poor Acceleration
F2: Engine Race Up (Slipping) During Acceleration
Control Valve Body ChecksInspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Sticking shift solenoid valve. Perform function check. Refer to On-Vehicle Service section.
• Clogged hydraulic circuit
Checks
Action
ChecksAction
Definition: • Starting acceleration is poor.
• Acceleration is slow, even though the accelerator pedal is stepped on during the running.
Diagnosis Hints In addition to the low engine output, faulty gearshift of the transmission or
fixing at the 3rd gear in the fail-safe operation may also be possible.
Therefore, if “maximum speed is low, and acceleration is poor”, it should be
cleared up whether the trouble originates from the engine system or
transmission control system by a running test, inspection of stall speed, etc.
Transmission Range Switch & Selector Lever
Cable Checks Inspect the transmission range switch and selector lever cable for
misadjusting or disordering. Refer to On-Vehicle Service section.
Transmission Fluid Checks Inspect the transmission fluid for the following conditions. If the transmission
fluid is extremely blacked, contaminated or smells burnt, slipping of clutch is
suspected.
• Low quantity
• Contamination
• Smell
Line Pressure Checks Inspect the line pressure in forward ranges for a possible dropped pressure.
Refer to Line Pressure Test in Test Instruction section.
Stall Speed Checks Inspect the stall speed in forward ranges. Refer to Stall Test in Test Instruction
section.
Control Valve Body Checks Inspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Sticking shift solenoid valve. Perform function check. Refer to On-Vehicle Service section.
• Clogged hydraulic circuit
Torque Converter Checks Inspect the torque converter for faulty operation.
Clutch and Brake Checks Inspect the low clutch and high clutch for slipping.
Additional Checks • Inspect the engine for proper outputs. Refer to appropriate inspection
chart in engine section.
• Inspect the TCM grounds for being clean, tight, and in their proper locations.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 99 or 100% according to the accelerator pedal
operation.
Checks Action
Definition: • Engine speed increases but the vehicle speed does not increase when the accelerator pedal is being stepped on.

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ISUZU KB P190 2007

7A2-116 TRANSMISSION CONTROL SYSTEM (JR405E)
G2: Large Creeping Force
G3: Small Creeping Force
G4: Large Noise During Idle with Vehicle Stop
Transmission Range Switch & Selector Lever
Cable Checks Inspect the transmission range switch and selector lever cable for
misadjusting or disordering. Refer to On-Vehicle Service section.
Additional Checks Inspect the parking mechanism for faulty operation. Checks Action
Checks
Action
Definition:
Vehicle accelerates in R, D, 3, 2 or L range, even though the accelerator pedal is not being stepped on.
Diagnosis Hints Too high idle speed is suspected. Inspect the engine for proper idle speed.
Checks Action
Definition:
Vehicle does not move, even though a run position is selected on a flat road during idling.
Diagnosis Hints When the creep force is small in all positions, low engine output is suspected.
If the creep is normal only in the R position, operation of the fail-safe function
due to trouble in the electrical system is suspected.
Transmission Fluid Checks Inspect the transmission fluid for the following conditions. If the transmission
fluid is extremely blacked, contaminated or smells burnt, slipping of clutch is
suspected.
• Low quantity
• Contamination
•Smell
Line Pressure Checks Inspect the line pressure in forward ranges for a possible dropped pressure.
Refer to Line Pressure Test in Test Instruction section.
Stall Speed Checks Inspect the stall speed in forward ranges. Refer to Stall Test in Test
Instruction section.
Control Valve Body Checks Inspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Sticking shift solenoid valve. Perform function check. Refer to On- Vehicle Service section.
• Clogged hydraulic circuit
Torque Converter Checks Inspect the torque converter for faulty operation.
Clutch and Brake Checks Inspect the low clutch for slipping.
Additional Checks • Inspect the engine for proper outputs. Refer to appropriate inspection
chart in engine section.
• Inspect the TCM grounds for being clean, tight, and in their proper locations.
• Inspect the ground return circuit for being clean, tight, and in their proper locations.
Checks Action
Definition:
Transmission is noisy during idle in all range.

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-117
H1: Judder Occurs at Lock Up
H2: Large Shock at Lock Up
H3: Lock Up Point is High or Low
I1: No Lock Up
Diagnosis Hints • Causes such as the solenoid operating sound or a faulty oil pump are
suspected.
• Distinguishing 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 other than the transmission may be generated around the engine, and should be checked carefully.
Notice: When the noise is generated only at the time of a gear shift, it may
be the sound of transmission fluid flowing 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 components. If the sound varies
depending on the vehicle speed, it may be the gear noise of the output
system, or the gear noise of the input system or a faulty torque converter.
Checks
Action
Checks Action
Definition:
Judder occurs when lock up area.
Diagnosis Hints Slip due to burning of the torque converter clutch (TCC) facing or insufficient
engagement due to dropped working pressure are suspected. Refer to
category No. “l1: No Lock Up “.
Notice: When the TCC facing has burnt, foreign material mixed in the oil
cooler is suspected. In such a case, inspect the oil cooler circuit for clogging
of the oil cooler.
Checks Action
Definition: • A large shock is felt at lock up.
• Lock up point is excessively high or low.
Diagnosis Hints Incorrect input signals or faulty operation of torque converter clutch (TCC) is
suspected. Refer to category No. “I1: No Lock Up”.
Checks Action
Definition:
Lock up is not performed even though lock up control conditions being satisfied.
Diagnosis Hints • Monitor the signal to the torque converter clutch (TCC) solenoid valve
while carrying out a running test.
• When the transmission fluid temperature is lower than 20 °C (68 °F),
lock up control is inhibited.
• When the output signal to the TCC solenoid valve is sent correctly, causing no lock up, clogged hydraulic circuits or malfunction of the TCC
piston may be suspected.
• Even with the lock up area, the output signal to the TCC solenoid valve is not sent, a fault of the transmission fluid temperature (TFT) sensor
controlling the lock up may be suspected.
Notice: When the TCC facing has burnt, foreign material mixed in the oil
cooler is suspected. In such a case, inspect the oil cooler circuit for clogging
of the oil cooler.

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ISUZU KB P190 2007

7A2-118 TRANSMISSION CONTROL SYSTEM (JR405E)
J1: Transmission Fluid Leaks from Breather
J2: Transmission Fluid Leaks Between Engine and Converter Housing
J3: Transmission Fluid Leaks Between Converter Housing and Transmission Case
J4: Transmission Fluid Leaks Between Transmission Case and Extension Housing
J3: Transmission Fluid Leaks from Oil Pan
J3: Transmission Fluid Leaks from Manual Shaft Oil Seal
J3: Transmission Fluid Leaks from Oil Cooler Pipe Joint
Z1: Transmission Overheat
Transmission Fluid Checks Inspect the transmission fluid for the following conditions. If the transmission
fluid is extremely blacked, contaminated or smells burnt, slipping of clutch is
suspected.
• Low quantity
• Contamination
• Smell
Control Valve Body Checks Inspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Sticking TCC solenoid valve. Perform function check. Refer to On- Vehicle Service section.
• Clogged hydraulic circuit
Sensor Checks Inspect the TFT sensor. Use the Temperature vs. Resistance table to test
the TFT sensor at various temperature levels to evaluate the possibility of a
skewed sensor.
Checks
Action
Checks Action
Definition:
Transmission fluid leaks from breather.
Diagnosis Hints Transmission fluid quantity is excessively high.
Checks Action
Definition:
Transmission fluid leaks between engine and converter housing.
Transmission fluid leaks between converter housing and transmission case.
Transmission fluid leaks between transmission case and extension housing.
Transmission fluid leaks from oil pan.
Transmission fluid leaks from manual shaft oil seal.
Transmission fluid leaks from oil cooler pipe joint.
Diagnosis Hints Faulty oil seal or contact surface is suspected.
Checks Action
Definition:
Smells burnt or smoke from transmission.
Diagnosis Hints • Transmission fluid quantity is excessively high.
• Slipping of the clutch is suspected. Gear ratio error DTC might be set.
• Clogged oil cooler.
• Faulty operation of oil pump.
• Faulty torque converter clutch (TCC) piston.

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-119
Z2: Mode Lamp (Power Drive or 3rd Start) Does Not Turn On
Z3: Mode Lamp (Power Drive or 3rd Start) Does Not Turn Off
Z4: A/T Oil Temperature Lamp Turns On
Z5: Selector Lever Feeling is Faulty
Z6: Poor Fuel Consumption
Checks Action
Definition:
Mode lamp on the instrument panel (IP) cluster does not turn ON even though the switch is ON.
Diagnosis Hints • Faulty mode switch circuit.
• Faulty mode switch.
• Faulty lamp control circuit.
• Faulty IP cluster.
Checks Action
Definition:
Mode lamp on the instrument panel cluster does not turn OFF even though the switch is OFF.
Diagnosis Hints • Faulty mode switch circuit.
• Faulty mode switch.
• Faulty lamp control circuit.
• Faulty IP cluster.
Checks Action
Definition:
A/T oil temperature lamp turns On sometimes.
Diagnosis Hints • If the fluid temperature increases to 135°C (275 °F), the TCM illuminates
A/T Oil Temp lamp on the instrument panel cluster. When the fluid
temperature deceases below 125 °C (257 °F), the lamp goes off.
• When the vehicle is stuck in the mud or continues to accelerate under overload, transmission fluid temperature increases and lamp may be
turned On.
• If the lamp is On under usual conditions, following causes are suspected. - Transmission fluid level has increased for some fault. Refer to category No. “Z1: Transmission Overheat”.
- Skewed transmission fluid temperature (TFT) sensor.
Checks Action
Definition:
Selector lever feeling is faulty.
Diagnosis Hints • Inspect the selector lever cable for misadjusting or disordering.
• Faulty manual plate.
Checks Action
Definition:
Poor fuel consumption.
Diagnosis Hints The same causes as in category No. “C1 - C8: Engine Race Up (Slipping)” are
suspected.

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ISUZU KB P190 2007

7A2-120 TRANSMISSION CONTROL SYSTEM (JR405E)
Z7: Shift Indicator is Faulty
Z8: Transmission Fluid is Splashed During Running
Z9: Abnormal Smell
Z10: Transmission Fluid Quantity is Low or High
Z11: Abnormal Transmission Fluid Pressure
Checks Action
Definition:
Shift indicator does not change even though the selector lever is moved.
Diagnosis Hints Inspect the transmission range switch and selector lever cable for
misadjusting or disordering. Refer to On-Vehicle Service section.
Checks Action
Definition:
Transmission Fluid is splashed during running.
Diagnosis Hints Transmission fluid quantity is excessively high.
Checks Action
Definition:
Abnormal smell.
Diagnosis Hints A trouble in the transmission main unit.
Checks Action
Definition:
Transmission fluid quantity is low or high.
Diagnosis Hints • If the fluid level is high, level check might be performed at low
temperature.
• If the fluid level is low, fluid leak is suspected.
Checks Action
Definition:
Transmission fluid pressure (TFP) is low or high.
Diagnosis Hints • Faulty pressure control (PC) solenoid valve or hydraulic circuits.
• If pressure is low, faulty oil pump is suspected.

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TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-121
Test Instructions
Line Pressure Test
Legend1. Oil cooler (outlet)
2. Low & reverse brake pressure detection port (R range line pressure detection port) 3. Low clutch pressure detection port (D, 3, 2, L range
line pressure detection port)
4. Oil cooler (inlet)
Line Pressure Test Procedure
1. Fully apply the parking brake and chock all wheels.
2. Check the level of the engine oil, coolant and transmission fluid. Replenish as necessary.
3. Remove the plug from either of the line pressure detection port (low & reverse brake pressure
detection port or low clutch pressure detection
port).
4. Install a pressure gauge to the line pressure detection port.
5. Start the engine and warm up (allow engine coolant temperature to reach at least 70 °C
[158 °F]).
Important: Keep the brakes applied at all times in
order to prevent unexpected vehicle motion. Personal
injury may result if the vehicle moves unexpectedly.
6. Let idle and record the line pressure when the selector lever is positioned R or D, 3, 2 and L
range. Important:
Line pressure test at the stall speed must
be finished within 5 seconds. Prolonged test time may
break the transmission.
7. Fully depress the brake pedal with your left foot.
8. Move the selector lever to the R or D range and fully depress the accelerator pedal. Record the line
pressure as soon as the stall speed.
9. Move the selector lever to the N range and let idle for at least 1 minute.
10. If the pressure gauge is connected to the low clutch pressure detection port, repeat the line
pressure test (step 7 to 9) at the stall speed in 3, 2
and L range.
11. Turn OFF the ignition.
12. Disconnect a pressure gauge from the line pressure detection port.
13. Tighten the plug.
1
2 3
4

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