Isuzu KB P190. Manual - part 1102

7A2-124   TRANSMISSION CONTROL SYSTEM (JR405E)

Time Lag Test

Time Lag 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. 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.

4. Let idle and record the time lag from when the

selector lever is moved from N to D or N to R range
until the shock has felt.

Standard Value

Diagnosis

1. If the time lag is out of the standard value when the

selector lever is moved from N to D range. 

• Forward range line pressure is low.

• Slipping of low clutch.

• Slipping of low one-way clutch.

• Problem in valve body (faulty operation, sticking or

clogged hydraulic circuit).

• Faulty operation of low clutch solenoid valve.

• Shorter or faulty amount of transmission fluid.

2. If the time lag is out of the standard value when the

selector lever is moved from N to R range.

• Reverse range line pressure is low

• Slipping of low & reverse brake

• Slipping of reverse clutch

• Problem in valve body (faulty operation, sticking or

clogged hydraulic circuit).

• Faulty operation of low & reverse brake solenoid

valve.

• Shorter or faulty amount of transmission fluid.

Selector lever position

Time lag 

N to D range

Less than 0.7 seconds

N to R range

Less than 1.2 seconds

TRANSMISSION CONTROL SYSTEM (JR405E)   7A2-125

Road Test

Road Test Procedure

*1: Shifting at high vehicle speed, the transmission may
hold the gear position until vehicle speed gets down to
prevent engine overruning. 
Notice: Perform this test at the normal transmission
fluid temperature between 50 to 80

°C (122 to 176°F).

Drive the vehicle on level ground so as not to change to
up slope mode and down slope mode.

1. D range road test in normal and power drive mode. 

• Select into the D range and hold the accelerator

pedal constant at the 50% and 100% accelerator
pedal position.

• 1 to 2, 2 to 3, 3 to 4 upshift and lock up should take

place, and shift points should match those shown
in the shift speed chart. 

• Also check to see that downshift is made from 4 to

3, 3 to 2 and 2 to 1 point is within the limits shown
in the shift speed chart.

2. 3 range road test in normal and power drive mode. 

• Select into the 3 range and hold the accelerator

pedal constant at the 50% and 100% accelerator
pedal position.

• 1 to 2, 2 to 3 upshift and lock up should take place,

and shift points should match those shown in the
shift speed chart. 

• While running in the 3 range, does not upshift from

3 to 4.

3. 2 range road test in normal mode.

• Select into the 2 range and hold the accelerator

pedal constant at the 50% and 100% accelerator
pedal position.

• 1 to 2 upshift should take place, and shift points

should match those shown in the shift speed chart. 

• While running in the 2 range, does not upshift from

2 to 3 or 3 to 4, and lock-up does not operate.

4. L range road test in normal mode. 

• While running in the L range, does not upshift from

1 to 2, 2 to 3 or 3 to 4, and lock-up does not
operate.

5. R range road test.

• Select into the R range and check for slipping.

6. P range road test.

• Stop the vehicle on a grade and release the park

brake after selecting into the P range. Then check
to see that the parking lock pawl holds the vehicle
in place.

Diagnosis

1. If there is no 1 to 2 upshift.

• Faulty operation of 2-4 brake

• Faulty operation of 2-4 brake hydraulic circuits

• Sticking of 2-4 brake solenoid valve 

• Refer to symptom diagnosis No. D1: Faulty Gear

Shifting or DTC P0731 - P0734 Incorrect Gear
Ratio diagnosis. 

2. If there is no 2 to 3 upshift.

• Faulty operation of high clutch

• Faulty operation of high clutch hydraulic circuits

• Sticking of high clutch solenoid valve 

• Refer to symptom diagnosis No. D1: Faulty Gear

Shifting or DTC P0731 - P0734 Incorrect Gear
Ratio diagnosis. 

3. If there is no 3 to 4 upshift.

• Faulty operation of 2-4 brake

• Faulty operation of 2-4 brake hydraulic circuits

• Sticking of 2-4 brake solenoid valve 

• Refer to symptom diagnosis No. D1: Faulty Gear

Shifting or DTC P0731 - P0734 Incorrect Gear
Ratio diagnosis.

4. If there is no lock up in 2nd, 3rd and 4th.

• Faulty operation of torque converter clutch (TCC)

piston

• Faulty operation of lock up hydraulic circuit 

• Sticking of TCC solenoid valve

• Refer to symptom diagnosis No. I1: No Lock-up

5. If there is no reverse.

• Faulty operation of reverse clutch

• Faulty operation of reverse clutch hydraulic circuits

• Faulty operation of low & reverse brake hydraulic

circuits

Selector lever

position

Gearshift

Selected gear

position

P

R

N

D

3

2

L

1st

2nd

3rd

4th

1st

2nd

3rd

4th(*1)

1st

2nd

3rd(*1)

4th(*1)

1st

2nd(*1)

3rd(*1)

4th(*1)

Reverse

7A2-126   TRANSMISSION CONTROL SYSTEM (JR405E)

• Sticking of low & reverse brake solenoid valve

• Refer to symptom diagnosis No. A2: Vehicle Dose

Not Run in R Range

6. If there is no parking.

• Faulty parking pawl

• Refer to symptom diagnosis No. G1: Vehicle

Moves in P Range or Parking Gear in Not
Disengaged other than P Range.

Notice: The check for the cause of abnormal noise and
vibration must be made with extreme care as it could
also be due to loss of balance in the propeller shaft,
differential, the torque converter, etc. Or insufficient
bending, rigidity, etc. in the powertrain.

Shift Speed Chart

1. All upshifts have a solid green line with:

• 1-2 has black filled diamond plot points

• 2-3 has black filled squre plot points

• 2-4 has back filled circular plot posints

2. All donwshift have a sloid blue line with:

• 2-1 has white filled diamonf plot points

• 3-2 has white filled squre plot points

• 4-3 has white filled circular plot points

3. Torque converter clutch apply points have a

dashed orange line with:

• 2nd apply has black filled diamond plot points

• 3rd apply has black filled squre plot points

• 4th apply has black filled circulat plot points

4. Torque converter clutch release points have a

dashed pink line with:

• 2nd release has white filled diamond plot points

• 3rd release has white filled squre plot points

• 4th release has white filled circulat plot points

TRANSMISSION CONTROL SYSTEM (JR405E)   7A2-127

RTW77AXF001001

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Normal mode/ Final gear ratio 41/11 (3.727)/ Tire size 215/70R15 (Euro 3 specification engine)

Power drive mode/ Final gear ratio 41/11(3.727)/ Tire size 215/70R15 (Euro 3 specification engine)

Accelerator

pedal

position

(%)

Vehicle speed (km/h)

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Accelerator

pedal

position

(%)

Vehicle speed (km/h)

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