2007 ISUZU KB P190 engine

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–70
Step Action Yes No
3 1 Inspect the shift solenoid/hydraulic circuit for the following
conditions:
• Debris or chips in the AFL oil passage.
• Debris or chips restricting oil flow in passage #29 of the
case or through the spacer plate gasket into the valve
body.
• A cracked 2-3 shift solenoid.
• A 2-3 shift valve which is stuck or hung up in the valve
body bore.
• A 2-3 shuttle valve which is stuck or hung up in its bore.
• Damaged seals on the shift solenoid valves. Perform the
shift solenoid leak test, refer to 7C3 Automatic
Transmission – 4L60E – Hydraulic and Mechanical
Diagnosis.
2 Clean and inspect the related valves, bores and the valve body for debris or contamination.
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 40%, and
• Accelerate to 64 km/h.
4 On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.
Has DTC P0756 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.
4.23 DTC P0757 – 2-3 Shift Solenoid Valve
Performance – No Third or Fourth Gear
DTC Description
This diagnostic procedure supports DTC P0757 2-3 Shift Solenoid (SS) Valve Performance – No Third or Fourth 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 1-2-2-1 shift pattern, then DTC P0757 sets. DTC P0757 is a
type A DTC.
Refer to 2 W iring Diagrams and Connector Chart to aid in diagnosis.

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–71
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
The TCM commands 3rd gear and the resulting gear ratio is a 1.44:1 – 1.52:1, 1st gear, for 2.25 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.
• The TCM inhibits 4th gear.
• 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 P0757 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 P0757, and then cannot reset DTC P0757, 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.

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–72
DTC P0757 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.
NOTE
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 1-2-2-1 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 15%, and
• Accelerate to 80 km/h.
4 On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.
Has DTC P0757 set? Go to Step 2 Go to Step 5

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–73
Step Action Yes No
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.
4.24 DTC P0787 – 3-2 Shift Solenoid Control
Circuit Low Voltage
DTC Description
This diagnostic procedure supports the following DTC:
DTC P0787 3-2 Shift Solenoid (SS) Control Circuit Low Voltage.
Circuit Description
The 3-2 shift solenoid (SS) valve is a normally-closed, 3-port, on/off device that controls the 3-2 downshift. The solenoid
attaches to the control valve body within the transmission. The solenoid receives ignition voltage through the ignition
circuit. The transmission control module (TCM) controls the solenoid by providing a ground path on the 3-2 shift solenoid
valve control circuit. During a 3-2 downshift, the 2-4 band applies as the 3-4 clutch releases. The TCM varies the timing
between the 3-4 clutch release and the 2-4 band apply depending on the vehicle speed and the throttle position.
When the TCM detects a continuous open or short to ground in the 3-2 SS valve circuit, then DTC P0787 sets.
DTC P0787 is a type A DTC.
Refer to 2 W iring Diagrams and Connector Chart to aid in diagnosis.
Conditions for Running the DTC
• The system voltage is 10 – 18 V.
• The engine speed is greater than 450 r.p.m. for 5 seconds.
• Vehicle speed is less than 200 km/h.
Conditions for Setting the DTC
The TCM commands the solenoid off and the voltage feedback remains low, 0 V.
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 commands 3rd gear.
• The TCM inhibits TCC engagement.
• 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 P0787 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.

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–74
• 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.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
4 Checks the ability of the TCM to control the solenoid.
5 Checks for supply voltage to the 3-2 SS valve.
6 Checks the ability of the TCM and wiring to control the ground circuit.
8 Checks the resistance of the control valve body wiring harness and the 3-2 SS valve.
9 Checks if the 3-2 SS or control valve body wiring harness is shorted to the transmission housing.
13 Checks if the control valve body wiring harness is shorted to ground.
14 Checks if any of the other solenoids in the transmission are shorted to ground.
DTC P0787 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.
NOTE
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.
Are any of the following DTCs also set?
• P0961
• P0973
• P0976
• P2764
• P2769. Go to Step 3 Go to Step 4
3 Inspect fuse C-8 and check if it is blown, refer to 8A Electrical-Body
and Chassis.
Is the fuse blown? Replace the fuse
Go to Step 12 Go to Step 5

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–75
Step Action Yes No
4 1 On Tech 2 select:
Automatic Transmission / Miscellaneous Tests / 3-2
Downshift Solenoid.
2 With Tech 2 command the 3-2 shift solenoid ON and
OFF .
Does Tech 2 display the 3-2 Downshift Solenoid as Active and
Inactive respectively? Check for an
intermittent fault in the circuit, refer to
8A Electrical-Body and Chassis Go to Step 5
5 1 Turn off the ignition.
2 Disconnect connector E-95 from the transmission.
NOTE
Additional DTCs may set
3 Install Tool No. J 44152 Jumper Harness (20 pins) on to the harness connector E-95.
4 Turn on the ignition, with the engine off.
5 Using a test lamp, probe between connector E-95 pin 10 and a known ground.
Does the test lamp illuminate? Go to Step 6 Test between
E-95 pin 10 and
C-107 pin 9 for an open circuit
Repalce affected circuit
Go to Step 18
6 1 Using a test lamp, probe connector E-95 pin 10 with the ground
lead to connector E-95 pin 11.
2 On Tech 2 select: Automatic Transmission / Miscellaneous Tests / 3-2
Downshift Solenoid.
3 With Tech 2 command the 3-2 shift solenoid ON and OFF three
times.
Does the test lamp turn on and off with each command? Go to Step 8 Go to Step 7
7 Is the test lamp always illuminates? Go to Step 15 Go to Step 16
8 1 Remove Tool No. J44152 from the harness connector E-95 and
install on to the transmission connector E-95.
2 Using a multimeter set to measure resistance, probe across transmission connector E-95 pins 10 and 11.
Does the multimeter display 20 – 32 Ω? Go to Step 9 Go to Step 10
9 1 Using a multimeter set to measure resistance, probe between:
• Transmission connector E-95 pin 10 and a known ground.
• Transmission connector E-95 pin 11 and a known ground.
Does the multimeter display greater than 250 k Ω in both instances? Check for an
intermittent fault in
the circuit, refer to
8A Electrical-Body
and Chassis Go to Step 11
10 1 Remove Tool No. J44152 from the transmission.
2 Gain access to the 3-2 SS and the control valve body wiring harness, refer to 7C4 Automatic Transmission – 4L60E – On-
vehicle Servicing.
3 Disconnect the internal connector from the 3-2 SS.
4 Using a multimeter set to measure resistance, probe across the 3-2 SS pins.
Does the multimeter display 20 – 32 Ω? Replace the control
valve body wiring
harness, refer to 7C4 Automatic
Transmission –
4L60E – On-vehicle
Servicing.
Go to Step 18 Replace the 3-2 SS,
refer to
7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing.
Go to Step 18

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–76
Step Action Yes No
11 1 Remove Tool No. J44152 from the transmission.
2 Gain access to the 3-2 SS and the control valve body wiring harness, refer to 7C4 Automatic Transmission – 4L60E – On-
vehicle Servicing.
3 Disconnect the internal connector from the 3-2 SS.
4 Using a multimeter set to measure resistance, probe between each of the 3-2 SS pins and the transmission case.
Does the multimeter display 250 k Ω in both instances? Replace the control
valve body wiring harness, refer to 7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing.
Go to Step 18 Replace the 3-2
shift solenoid, refer to 7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing.
Go to Step 18
12 Using a multimeter, test between E-95 pin 10 and C-107 pin 9 for a
short to ground.
Did you find and correct the condition? Go to Step 18 Go to Step 13
13 1 Gain access to the control valve body wiring harness, refer to
7C4 Automatic Transmission – 4L60E – On-vehicle Servicing.
2 Test for a short to ground in the control valve body wiring harness.
Did you find a short to ground condition? Replace the control
valve body wiring harness, refer to 7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing.
Go to Step 18 Go to Step 14
14 1 Test each solenoid in the transmission for a short to ground,
refer to 8A Electrical-Body and Chassis.
2 Replace the faulty solenoid as necessary.
Did you complete the replacement? Go to Step 18 —
15 Using a multimeter, test between E-95 pin 11 and C-96 pin 14 for a
short to ground.
Did you find and correct the condition? Go to Step 18 Go to Step 17
16 Using a multimeter, test between E-95 pin 11 and C-96 pin 14 for an
open circuit.
Did you find and correct the condition? Go to Step 18 Go to Step 17
17 Replace the TCM, refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing.
Did you complete the replacement? Go to Step 18
—
18 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 On Tech 2 select: Automatic Transmission / Data Display / Transmission Data.
4 Drive the vehicle in D3 or D4 and perform a 3-2 downshift. Ensure the 3-2 Downshift Solenoid parameter displays On
when the shift occurs.
5 On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.
Has DTC P0787 set? Go to Step 2 Go to Step 19
19 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

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–77
Step Action Yes No
When all diagnosis and repairs are completed, check the system for correct operation.
4.25 DTC P0788 – 3-2 Shift Solenoid Control
Circuit High Voltage
DTC Description
This diagnostic procedure supports DTC P0788 3-2 Shift Solenoid (SS) Control Circuit High Voltage.
Circuit Description
The 3-2 shift solenoid (SS) valve is a normally-closed, 3-port, on/off device that controls the 3-2 downshift. The solenoid
attaches to the control valve body within the transmission. The solenoid receives ignition voltage through the ignition 1
circuit. The transmission control module (TCM) controls the solenoid by providing a ground path on the 3-2 shift solenoid
valve control circuit. During a 3-2 downshift, the 2-4 band applies as the 3-4 clutch releases. The TCM varies the timing
between the 3-4 clutch release and the 2-4 band apply depending on the vehicle speed and the throttle position.
When the TCM detects a continuous short to voltage in the 3-2 shift solenoid valve control circuit, then DTC P0788 sets.
DTC P0788 is a type A DTC.
Refer to 2 W iring Diagrams and Connector Chart to aid in diagnosis.
Conditions for Running the DTC
• The system voltage is 10 – 18 V.
• The engine speed is 450 r.p.m. for 5 seconds.
• The engine is not in fuel cut off.
Conditions for Setting the DTC
DTC P0788 sets if the TCM commands the solenoid on and the voltage feedback remains high, battery voltage.
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 commands 3rd gear.
• The TCM inhibits TCC engagement.
• 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 P0788 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.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007