2007 ISUZU KB P190 DTC CHECK

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 7C2–77
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.

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–78
Test Description
The following numbers refer to the step numbers in the diagnostic table:
2 Checks for a short to voltage in the 3-2 SS signal circuit.
3 Checks for the serviceability of the 3-2 SS.
DTC P0788 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 Turn off the ignition.
8 Disconnect connector E-95 from the transmission.
NOTE
Additional DTCs may set
9 Install Tool No. J 44152 Jumper Harness (20 pins) on to the harness connector E-95.
10 Turn on the ignition, with the engine off.
11 Using a test lamp and Tool No. J 35616-C, probe between connector E-95 pin 11 and a known ground.
Does the test lamp illuminate? Go to Step 5 Go to Step 3
3 1 Install Tool No. J 44152 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 less than 20 Ω? Go to Step 4 Go to Step 6

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ISUZU KB P190 2007

Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–79
Step Action Yes No
4 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 less than 20 Ω? Replace the 3-2 SS,
refer to
7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing
Go to Step 7 Replace the control
valve body wiring harness, refer to 7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing.
Go to Step 7
5 Using a multimeter, test between E-95 pin 11 and C-96 pin 14 for a
short to voltage.
Did you find and correct the condition? Go to Step 7 Go to Step 6
6 Replace the TCM, refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing.
Did you complete the replacement? Go to Step 7 —
7 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 and Off in all other instances
5 On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.
Has DTC P0787 set? Go to Step 2 Go to Step 8
8 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.
4.26 DTC P0894 – Transmission Component
Slipping
DTC Description
This diagnostic procedure supports DTC P0894 Transmission Component Slipping.
Circuit Description
The transmission control module (TCM) monitors the difference between engine speed and transmission output speed.
In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed. In D4
drive range, with the TCC engaged, the TCC slip speed should be -20 to +50 r.p.m.
W hen the TCM detects excessive TCC slip when the TCC should be engaged, then DTC P0894 sets. DTC P0894 is a
type B DTC.
Refer to 2 W iring Diagrams and Connector Chart to aid in diagnosis.

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Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–81
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 TCC.
• The TCM inhibits 4th gear if in hot mode.
• 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 P0894 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
•
Bronze material found in the transmission oil pan may indicate stator shaft bushing wear. If bushing wear is
suspected, inspect the stator shaft and the input, turbine, shaft for damage.
• Perform the Torque Converter Diagnosis Procedure, refer to 7C3 Automatic Transmission – 4L60E – Hydraulic and
Mechanical Diagnosis.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
3 Checks the torque converter for slippage while in a commanded lock-up state.
4-12 Checks the mechanical components that cause the DTC and their state.
13 W hen the TAP cells are cleared the TCM needs to relearn the TAP cells for the transmission. As such, when the vehicle is first driven, the shifts may be harsh. The transmission shifts should become smoother the more the
vehicle is driven until the TCM has relearned all TAP cells.
DTC P0894 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 Inspect for correct transmission fluid level, refer to 7C4 Automatic
Transmission – 4L60E – On-vehicle Servicing.
Did you perform the fluid checking procedure?
Go to Step 3 Check the
transmission fluid level, refer to
7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing

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Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–86
Step Action Yes No
14 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 Operate the vehicle under the following conditions:
• Drive the vehicle in D4, with the TCC on, and a throttle
position at 20%.
• On Tech 2 ensure the TCC Slip Speed is -20 to +50 RPM
for at least 7 seconds.
5 On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.
Has DTC P0894 set? Go to Step 2 Go to Step 15
15 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.
4.27 DTC P0961 – Line Pressure Control
Solenoid System Performance
DTC Description
This diagnostic procedure supports DTC P0961 Line Pressure Control (PC) Solenoid System Performance.
Circuit Description
The pressure control (PC) solenoid valve is an electronic device that regulates transmission line pressure based on the
current flow through its coil winding. The magnetic field produced by the coil moves the solenoid's internal valve, which
varies pressure to the pressure regulator valve. The transmission control module (TCM) controls the PC solenoid valve
by applying a varying amount of current to the solenoid. The applied current can vary from 0.1 – 1.1 A. Low current,
0.1 A, indicates high line pressure. High current, 1.1 A, indicates low line pressure. The duty cycle of the PC solenoid
valve is expressed as a percentage of energised on time. Zero percent indicates zero on time, non-energised, or no
current flow. Approximately 60 percent at idle indicates maximum on time, energised, or high current flow. The TCM
determines the appropriate line pressure for a given load by comparing the throttle position, the engine speed and other
inputs.
W hen the TCM detects a continuous open or short to ground in the PC solenoid valve circuit, then DTC P0961 sets.
DTC P0961 is a type C DTC.
Refer to 2 W iring Diagrams and Connector Chart to aid in diagnosis.
Conditions for Running the DTC
• The system voltage is 8 – 18 V.
• The engine is running.
Conditions for Setting the DTC
The PC solenoid valve duty cycle reaches its high limit, approximately 95 percent, or low limit, approximately 2 percent.
Action Taken When the DTC Sets
• The TCM does not request the engine control module (ECM) to illuminate the MIL.

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Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–87
• The TCM records the operating conditions when the conditions for setting the DTC are met. The TCM records this
information as a Failure Record.
• The TCM freezes transmission adaptive functions.
• The TCM commands maximum line pressure.
• The TCM stores DTC P0961 in TCM history.
Conditions for Clearing 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.
• Tech 2 can clear the DTC.
Diagnostic Aids
DTC P0961 may set under low voltage conditions caused by high electrical system demands.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
2 Checks the ability of the TCM to control the solenoid.
3 Checks the resistance of the control valve body wiring harness and the PC solenoid.
5 Checks the serviceability of the PC solenoid circuits contained in the control valve body wiring harness.
6-8 Checks the serviceability the power and signal circuits between the TCM and the transmission.
DTC P0961 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

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Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–88
Step Action Yes No
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 On Tech 2 select: Miscellaneous Tests / Pressure Control Solenoid.
8 Using Tech 2, turn the pressure control solenoid on and off three times.
Does Tech 2 display the PCS as On and Off when commanded by
Tech 2? Check for an
intermittent fault in the circuit, refer to
8A Electrical-Body and Chassis Go to Step 3
3 1 Turn off the ignition.
2 Disconnect connector E-95 from the transmission.
3 Install Tool No. J 44152 Jumper Harness (20 pins) on to the transmission connector E-95.
4 Using the multimeter set to measure resistance, probe across transmission connector E-95 pins 1 and 2.
Does the multimeter display 3 – 7 Ω? Go to Step 4 Go to Step 5
4 Using the multimeter set to measure resistance, probe between
connector E-95 pin 2 and the transmission case.
Does the multimeter display greater than 250 k Ω? Go to Step 6 Go to Step 5
5 Using a multimeter, test between E-95 pin 1 & E-95 pin 2 and the
solenoid for the following:
• open circuit,
• short together, and
• short to ground.
Did you find any of the conditions tested? Replace the control
valve body wiring harness, refer to 7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing.
Go to Step 11 Replace the PC
solenoid valve, refer to 7C4 Automatic
Transmission –
4L60E – On-vehicle Servicing
Go to Step 11
6 1 Disconnect Tool No. J 44152 from connector E-95.
2 Connect E-95 to the transmission.
3 Disconnect connector E-95 from the TCM.
4 Using a multimeter set to measure resistance, probe between connector C-96 pins 17 and 40.
Does the multimeter display 3 – 7 Ω? Go to Step 7 Go to Step 8

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ISUZU KB P190 2007