Isuzu KB P190. Manual — part 963
Automatic Transmission – 4L60E – Electrical Diagnosis
Page 7C2–66
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.
•
The TCM inhibits 3-2 downshifts if the vehicle speed is greater than 40 km/h.
•
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 P0752 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.
Diagnostic Aids
•
If you clear DTC P0752, and then cannot reset DTC P0752, 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:
2
This step tests the TCM commanded all shifts, all shift solenoid valves responded correctly, and if all the shifts did
not occur.
3
Checks the mechanical components that cause the DTC and their state.
DTC P0752 Diagnostic Table
Step Action
Yes
No
1
Has the Diagnostic System Check been performed?
Go to Step 2
Refer to
4.7 Diagnostic
System Check
Automatic Transmission – 4L60E – Electrical Diagnosis
Page 7C2–67
Step Action
Yes
No
2
1
Connect Tech 2 to the DLC.
2
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.
3
On Tech 2 select:
Transmission / Automatic Transmission / Diagnostic
Trouble Codes / Freeze Frame.
4
Select the relevant DTC and note the parameters at the time of
the DTC setting.
5
On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.
6
Follow the instructions on Tech 2 and clear the DTCs.
7
Drive the vehicle in D4 range under the following conditions:
•
Accelerate the vehicle, and
•
Ensure the TCM commands 1st, 2nd, 3rd and 4th gears.
Did you detect a 1-1-4-4 shift pattern?
Go to Step 3
Refer to Diagnostic
Aids within this
Section
3
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
—
4
Perform the following procedure to verify the repair:
1
On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs
2
Follow the instructions on Tech 2 and clear any DTCs.
3
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.
4
On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.
Has DTC P0752 set?
Go to Step 2
Go to Step 5
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 7C2–68
4.22 DTC P0756 – 2-3 Shift Solenoid Valve
Performance – No First or Second Gear
DTC Description
This diagnostic procedure supports DTC P0756 2-3 Shift Solenoid (SS) Valve Performance – No First or Second Gear.
Circuit Description
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves. The 2-3 SS valve is a normally-
open exhaust valve that is used with the 1-2 SS valve, to allow four different shifting combinations.
When the transmission control module (TCM) detects a 4-3-3-4 shift pattern, then DTC P0756 sets. DTC P0756 is a
type A DTC.
Refer to 2
Wiring Diagrams and Connector Chart to aid in diagnosis.
Conditions for Running the DTC
•
No DTCs P0120, P0722, P0723, P0742, P0973, P0974, P0976, P0977 or P1815.
•
The engine torque is 108 – 882 Nm.
•
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.
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 when the output shaft speed is 200 r.p.m. or greater, the engine torque
is 40 – 350 Nm, and the resulting gear ratio is 0.73:1 – 0.77:1 for 2.8 seconds.
•
Fail Case 2: The TCM commands 2nd gear when the engine torque is 36 – 350 Nm and the resulting gear ratio is
1.56:1 – 1.64:1 for 1 second.
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 inhibits 1st gear.
•
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 P0756 in TCM history.
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.
Automatic Transmission – 4L60E – Electrical Diagnosis
Page 7C2–69
•
The TCM cancels the DTC default actions when the ignition is off long enough to power down the TCM.
Diagnostic Aids
•
If you clear DTC P0756, and then cannot reset DTC P0756, 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:
2
This step tests the TCM commanded all shifts, all shift solenoid valves responded correctly, and if all the shifts did
not occur.
3
Checks the mechanical components that cause the DTC and their state.
DTC P0756 Diagnostic Table
Step Action
Yes
No
1
Has the Diagnostic System Check been performed?
Go to Step 2
Refer to
4.7 Diagnostic
System Check
2
1
Connect Tech 2 to the DLC.
2
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.
3
On Tech 2 select:
Transmission / Automatic Transmission / Diagnostic
Trouble Codes / Freeze Frame.
4
Select the relevant DTC and note the parameters at the time of
the DTC setting.
5
On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.
6
Follow the instructions on Tech 2 and clear the DTCs.
7
Drive the vehicle in D4 range under the following conditions:
•
Accelerate the vehicle, and
•
Ensure the TCM commands 1st, 2nd, 3rd and 4th gears.
Did you detect a 4-3-3-4 shift pattern?
Go to Step 3
Refer to Diagnostic
Aids within this
Section
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