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Isuzu KB P190. Manual - part 962

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–62

Step Action

Yes

Connect Tech 2 to the DLC.

Turn on the ignition, with the engine off.

N O T E

Before clearing the DTC, use the Tech

2 Freeze

Frame/Failure Record to record the transmission
parameters at the time the DTC set. Using Tech 2 to clear
the DTC(s) erases the Freeze Frame/Failure Record
records from the TCM.

On Tech 2 select:
Transmission / Automatic Transmission / Diagnostic
Trouble Codes / Freeze Frame.

Select the relevant DTC and note the parameters at the time of
the DTC setting.

On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.

Follow the instructions on Tech 2 and clear the DTCs.

On Tech 2 select:
Automatic Transmission / Data Display / Transmission Data.

Drive the vehicle in the D4 drive range in second, third, or fourth
gear under steady acceleration, with a TP angle at 10%.

On Tech 2, while TCC Solenoid status is On, is the TCC Slip Speed
within -20 to +20 RPM?

Go to Step 3

Refer to Diagnostic

Aids within this

Section

The TCC is hydraulically stuck ON. Inspect for the following:

•

Blocked exhaust orifice in the TCC solenoid valve.

•

Converter clutch apply valve stuck in the apply position.

•

Incorrectly aligned or damaged valve body gasket.

•

Restricted release passage.

•

Restricted transmission cooler line.

Did you find and correct the condition?

Go to Step 4

—

Perform the following procedure to verify the repair:

On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.

Follow the instructions on Tech 2 and clear any DTCs.

On Tech 2 select:
Automatic Transmission / Data Display / Transmission Data.

Drive the vehicle in D4 with the TCC ON and the throttle above
10%. Ensure Tech 2 displays TCC Slip Speed between 100 –
2,500 RPM for 3 seconds.

On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.

Has DTC P0742 set?

Go to Step 2

Go to Step 5

On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.

Does Tech 2 display any DTCs you have not diagnosed?

Refer to

4.8 Diagnostic

Trouble Code List

System OK

When all diagnosis and repairs are completed, check the system for correct operation.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–63

4.20 DTC P0751 – 1-2 Shift Solenoid Valve

Performance – No First or Fourth Gear

DTC Description

This diagnostic procedure supports DTC P0751 1-2 Shift Solenoid (SS) Valve Performance – No First or Fourth Gear.

Circuit Description

The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The 1-2 SS valve is a
normally-open exhaust valve that is used with the 2-3 SS valve, to allow four different shifting combinations.

If the transmission control module (TCM) detects a 2-2-3-3 shift pattern, then DTC P0751 sets. DTC P0751 is a type B
DTC.

Refer to 2

Wiring Diagrams and Connector Chart to aid in diagnosis.

Conditions for Running the DTC

•

No DTCs P0722, P0723, P0742, P0894, P0973, P0974, P0976, P0977 or P1815.

•

Ignition voltage is 8 – 18 V.

•

The engine r.p.m. is 500 – 6,500 r.p.m. for greater than 5 seconds.

•

The transmission fluid temperature is 20 – 130°C.

•

The throttle position is greater than 10 percent.

•

The input shaft speed is 200 – 6,800 r.p.m.

•

The output shaft speed is greater than 100 r.p.m.

Conditions for Setting the DTC

Both of the following conditions must occur twice during the same trip:

•

Fail Case 1: The TCM commands 1st gear and the resulting gear ratio is 1.44:1 – 1.50:1 for 2 seconds.

•

Fail Case 2: The TCM commands 4th gear and the resulting gear ratio is 0.98:1 – 1.03:1 for 4 seconds.

Action Taken When the DTC Sets

•

The TCM requests the ECM to illuminate the MIL during the second consecutive trip in which the Conditions for
Setting the DTC are met.

•

The TCM commands maximum line pressure.

•

The TCM freezes transmission adaptive functions.

•

At the time of the first failure, the TCM records the operating conditions when the conditions for setting the DTC are
met. The TCM stores this information as a Failure Record.

•

At the time of the second failure, the ECM records the operating conditions when the conditions for setting the DTC
are met. The ECM stores this information as a Freeze Frame.

•

The TCM stores DTC P0751 in TCM history during the second consecutive trip in which the conditions for setting
the DTC are met.

Conditions for Clearing the DTC

•

The ECM turns off the MIL after the fourth consecutive drive trip in which the TCM does not send a MIL illumination
request.

•

Tech 2 can clear the DTC.

•

The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission
related diagnostic fault occurring.

•

The TCM cancels the DTC default actions when the ignition is off long enough to power down the TCM.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–64

Diagnostic Aids

•

If you clear DTC P0751, and then cannot reset DTC P0751, the following conditions may exist:

•

Fluid contamination,

•

Blocked fluid circuits, or

•

Restricted fluid circuits.

•

Refer to 5.6 Shift Solenoid Valve State and Gear Ratio.

Test Description

The following numbers refer to the step numbers in the diagnostic table:

This step tests the TCM commanded all shifts, all shift solenoid valves responded correctly, and if all the shifts did
not occur.

Checks the mechanical components that cause the DTC and their state.

DTC P0751 Diagnostic Table

Step Action

Yes

Has the Diagnostic System Check been performed?

Go to Step 2

Refer to

4.7 Diagnostic

System Check

Connect Tech 2 to the DLC.

Turn on the ignition, with the engine off.

N O T E

Before clearing the DTC, use the Tech

2 Freeze

Frame/Failure Record to record the transmission
parameters at the time the DTC set. Using Tech 2 to clear
the DTC(s) erases the Freeze Frame/Failure Record
records from the TCM.

On Tech 2 select:
Transmission / Automatic Transmission / Diagnostic
Trouble Codes / Freeze Frame.

Select the relevant DTC and note the parameters at the time of
the DTC setting.

On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.

Follow the instructions on Tech 2 and clear the DTCs.

Drive the vehicle in D4 range under the following conditions:

•

Accelerate the vehicle

•

Ensure the TCM commands 1st, 2nd, 3rd and 4th gears.

Did you detect a 2-2-3-3 shift pattern?

Go to Step 3

Refer to Diagnostic

Aids within this

Section

Inspect the shift solenoid/hydraulic circuit for the following conditions:

•

An internal malfunction.

•

Damaged seals on the shift solenoid valve. Perform the shift
solenoid leak test, refer to 7C3 Automatic Transmission – 4L60E
– Hydraulic and Mechanical Diagnosis.

Did you find and correct the condition?

Go to Step 4

—

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–65

Step Action

Yes

Perform the following procedure to verify the repair:

On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs

Follow the instructions on Tech 2 and clear any DTCs.

Drive the vehicle in D4 range under the following conditions,
only if traffic and road conditions permit:

•

Hold the throttle at 20%, and

•

Accelerate to 88 km/h.

On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.

Has DTC P0751 set?

Go to Step 2

Go to Step 5

On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.

Does Tech 2 display any DTCs you have not diagnosed?

Refer to

4.8 Diagnostic

Trouble Code List

System OK

When all diagnosis and repairs are completed, check the system for correct operation.

4.21 DTC P0752 – 1-2 Shift Solenoid Valve

Performance – No Second or Third Gear

DTC Description

This diagnostic procedure supports DTC P0752 1-2 Shift Solenoid (SS) Valve Performance – No Second or Third Gear.

Circuit Description

When the transmission control module (TCM) detects a 1-1-4-4 shift pattern, then DTC P0752 sets. DTC P0752 is a
type B DTC.

Refer to 2

Wiring Diagrams and Connector Chart to aid in diagnosis.

Conditions for Running the DTC

•

No DTCs P0722, P0723, P0742, P0894, P0973, P0974, P0976, or P0977.

•

Ignition voltage is 8 – 18 V.

•

The engine run time is greater than 5 seconds.

•

The transmission fluid temperature is 20 – 130°C.

•

The throttle position is greater than 10 percent.

•

The output shaft speed is greater than 150 r.p.m.

•

The engine torque is 108 – 882 Nm.

Conditions for Setting the DTC

The TCM commands 2nd gear and the resulting gear ratio is 2.42:1 – 2.52:1, 1st gear ratio for 2 seconds twice during
the same trip.

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