Isuzu KB P190. Manual - part 1098

 

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Isuzu KB P190. Manual - part 1098

 

 

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

Checks

Action

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. 

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

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. 

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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