2007 ISUZU KB P190 engine

7A2-104 TRANSMISSION CONTROL SYSTEM (JR405E)
B2: Poor Acceleration at Starting
Transmission Fluid ChecksInspect 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 shift solenoid valve. Perform function check. Refer to On-Vehicle Service section.
• Clogged hydraulic circuit
Clutch and Brake Checks Inspect the low clutch, reverse clutch, low one-way clutch and low & reverse brake for
seizing.
Checks
Action
ChecksAction
Definition:
Starting acceleration is poor.
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.

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-105
B3: Engine Races Up During Starting (Slip)
B4: Large Shock When Selector Lever is Changed from N to D Range or N to R Range
Checks Action
Definition:
The engine speeds up but the vehicle speed does not increase when the accelerator pedal is stepped on at starting.
Diagnosis Hints Slipping of the clutch is suspected. Gear ratio error DTC might be set.
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
Clutch and Brake Checks Inspect any 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:
A large shock is felt when the selector lever is changed from N to D or N to R during idle.
Diagnosis Hints • Check the vehicle side such as exhaust mounting and engine mounting.
• With the fail-safe operation, garage shock may grow worth. If there is no DTC, faulty operation of the control valve or seized clutch might be suspected.
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.
Line Pressure Test Inspect the line pressure in D range or R range for a possible high or low pressure.
Refer to Line Pressure 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 any clutch for seizing.
Additional Checks • Inspect the transmission input signals.
• Inspect the engine for proper idle speed.
• Inspect the suspension for play.

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ISUZU KB P190 2007

7A2-106 TRANSMISSION CONTROL SYSTEM (JR405E)
B5: Engine Stalls When Selector Lever is Changed from N to R, D, 3, 2 or L Range
B6: Engine Does Not Crank in P or N Range
B7: Engine Cranks in other than P or N Range
B8: Extended Time Lag When Selector Lever is Changed from N to D
Checks Action
Definition:
The engine stalls when selector lever is changed from N or P position to a run position during engine idling.
Diagnosis Hints • As the correct cause is attributable to the engine, faulty idle up, insufficient
engine output, etc. are suspected.
• As this is a cause of the transmission, faulty torque converter clutch (TCC) piston is suspected.
• If the transmission fluid through resistance increases due to clogged oil cooler or some other reason, or if the transmission fluid level decreases, the TCC piston
works causing the engine stall.
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 lock up spool valve
• Sticking TCC solenoid valve. Perform function check. Refer to On-Vehicle Service section.
• Clogged hydraulic circuit
Additional Checks • Inspect the engine for proper outputs. Refer to appropriate inspection chart in
engine section.
• Inspect the engine for proper idle speed.
Checks Action
Definition: • The engine starter does not run even though the P or N range.
• The engine starter runs even though the R, D, 3, 2 or L 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.
Checks Action
Definition:
The shift time lag is longer than the standard value when the selector lever is changed from N to D.
Transmission Fluid Checks Inspect the transmission fluid for low quantity.
Line Pressure Checks Inspect the line pressure in D range for a possible dropped pressure. Refer to Line
Pressure Test in Test Instruction section.

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ISUZU KB P190 2007

7A2-108 TRANSMISSION CONTROL SYSTEM (JR405E)
B12: Noise or Vibration Occurs at Starting
C1: Engine Race Up (Slipping) When Gearshift is Up from 1st to 2nd
C2: Engine Race Up (Slipping) When Gearshift is Up from 2nd to 3rd
C3: Engine Race Up (Slipping) When Gearshift is Up from 3rd to 4th
C4: Engine Race Up (Slipping) When Gearshift is Down from 4th to 3rd
C5: Engine Race Up (Slipping) When Gearshift is Down (or Kick-down) from 4th to 2nd
C6: Engine Race Up (Slipping) When Gearshift is Down (or Kick-down) from 3rd to 2nd
C7: Engine Race Up (Slipping) When Gearshift is Down (or Kick-down) from 4th or 3rd to 2nd
C8: Engine Race Up (Slipping) Others
Control Valve Body Checks Inspect the valve body for the following conditions.
• Faulty operation
• Sticking spool valve
• Clogged hydraulic circuit
Clutch and Brake Checks Inspect the low clutch, reverse clutch, low one-way clutch or low & reverse brake for
slipping.
Checks
Action
ChecksAction
Definition:
Noise or vibration occurs in the vicinity of the transmission at starting.
Diagnosis Hints Cause other than transmission is suspected. Reproduce the running condition using
a lift up, chassis dynamo, etc. to investigate the origin of the noise and vibration.
Additional Checks • Inspect the differential gear noise.
• Inspect the propeller shaft noise.
• Inspect the tires for unbalanced or poor uniformity.
Checks Action
Definition: • Engine speed-up occurs when the accelerator pedal is stepped on for acceleration, and the gear is shifted up.
• Engine speed-up occurs when the accelerator pedal is stepped on for acceleration, and the gear is shifted down or for kick-down during steady run.
• Engine speed-up occurs when the accelerator pedal is stepped on for acceleration, and the gear is shifted down or for kick-down during steady run.
Diagnosis Hints Slipping of the clutch is suspected. Gear ratio error DTC might be set.
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.

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-109
C9: Braking Feel When Gearshift is Up from 1st to 2nd
C10: Braking Feel When Gearshift is Up from 2nd to 3rd
C11: Braking Feel When Gearshift is Up from 3rd to 4th
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
Clutch and Brake Checks Inspect any 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:
A braking feeling occurs when the accelerator pedal is stepped on for acceleration, and the gear is shifted up.
Diagnosis Hints Slipping of the clutch is suspected. Gear ratio error DTC might be set.
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
Clutch and Brake Checks Inspect any 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

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ISUZU KB P190 2007

7A2-110 TRANSMISSION CONTROL SYSTEM (JR405E)
C12: Large Shock When Gearshift from 1st to 2nd or 2nd to 1st
C13: Large Shock When Gearshift from 2nd to 3rd or 3rd to 2nd
C14: Large Shock When Gearshift from 3rd to 4th or 4th to 3rd
C15: Large Shock When Kick-down
C16: Large Shock When Accelerator Pedal is Stepped ON or OFF without Gearshift
C17: Large Shock When Gearshift from 2nd to 1st in L Range
C18: Large Shock Others
C19: Large Shock When Vehicle Speed is Reduced by No Accelerator Pedal or Vehicle is Stopped
C20: Large Shock at Lock Up
C21: Shift Down or Engine Overrun When Accelerator Pedal is Stepped ON in 4th Gear
D1: Faulty Gearshift Schedule (Different from Shift Speed Chart)
Checks Action
Definition: • A large shock is felt when the accelerator pedal is stepped on for acceleration and the gear is shifted up or down.
• A large shock is felt when the accelerator pedal is stepped on for kick-down.
• A large shock is felt when the accelerator pedal is not stepped on.
• A large shock is felt when the selector lever is selected in L range.
Diagnosis Hints The same causes as in category No. “C1 - C8: Engine Race Up (Slipping)” are
suspected.
Checks Action
Definition:
A large shock is felt at lock up.
Diagnosis Hints Incorrect input signals or faulty operation of torque converter clutch is suspected.
Refer to category No. “I1: No Lock Up.”
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.
Checks Action
Definition:
Faulty gearshift schedule, it is differ from the shift speed chart.

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ISUZU KB P190 2007

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