2007 ISUZU KB P190 lock

7A2-58 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P0753 (Flash Code 31)
Circuit Description
The low & reverse brake solenoid valve controls fluid
acting on spool valves in the low & reverse brake
hydraulic circuits, which then controls low & reverse
brake apply and release. The solenoid valve is installed
to the lower part of the valve body assembly. The TCM
controls the solenoid valve by a duty cycle (pulse width
modulation [PWM]) signal based on the commanded
gear position. The solenoid valve provides a smooth
gearshift by operating on a duty cycle percentage of
ON time. The TCM monitors the low & reverse brake
solenoid valve operating status through the feedback
circuit. If the TCM detects an improper voltage level on
the control circuit, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects an open circuit or short circuit on the low & reverse brake solenoid valve control
circuit.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails.
During the vehicle running;
• The TCM holds the last gear position when the diagnostic runs and fails. • The TCM stops low & reverse brake solenoid
valve.
• The TCM inhibits lock up control.
After the vehicle stopped;
• The TCM stops all shift solenoid valves and fixes to the 3rd gear. If a fail-safe valve problem is
detected, the shift solenoid valves are not stopped
but gear is fixed to the 3rd gear.
• The TCM stops PC solenoid valve.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail at next
ignition cycle.
• A current DTC clears when the diagnostic runs and does not fail at next ignition cycle.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Use the Clutch, Brake, Solenoid and Pressure Switch Logic table to verify each component works
properly within the selected gear range.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0753
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check - Transmission Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Is DTC P1875 also set? —
Go to DTC P1875 Go to Step 3
3 1. Park the vehicle.
2. Turn ON the ignition, with the engine OFF.
3. Perform the Low & Reverse Brake Solenoid control with a scan tool.
4. Command the solenoid valve ON and OFF.
Does the low & reverse brake solenoid valve click
with each command? —
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-61
DTC P0758 (Flash Code 32)
Circuit Description
The 2-4 brake solenoid valve controls fluid acting on
spool valves in the 2-4 brake hydraulic circuits, which
then controls 2-4 brake apply and release. The
solenoid valve is installed to the lower part of the valve
body assembly. The TCM controls the solenoid valve
by a duty cycle (pulse width modulation [PWM]) signal
based on the commanded gear position. The solenoid
valve provides a smooth gearshift by operating on a
duty cycle percentage of ON time. The TCM monitors
the 2-4 brake solenoid valve operating status through
the feedback circuit. If the TCM detects an improper
voltage level on the control circuit, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects an open circuit or short circuit on the 2-4 brake solenoid valve control circuit.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails.
During the vehicle running;
• The TCM holds the last gear position when the diagnostic runs and fails.
• The TCM stops 2-4 brake solenoid valve. • The TCM inhibits lock up control.
After the vehicle stopped;
• The TCM stops all shift solenoid valves and fixes to the 3rd gear. If a fail-safe valve problem is
detected, the shift solenoid valves are not stopped
but gear is fixed to the 3rd gear.
• The TCM stops PC solenoid valve.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail at next
ignition cycle.
• A current DTC clears when the diagnostic runs and does not fail at next ignition cycle.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Use the Clutch, Brake, Solenoid and Pressure Switch Logic table to verify each component works
properly within the selected gear range.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0758
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check - Transmission Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Is DTC P1875 also set? —
Go to DTC P1875 Go to Step 3
3 1. Park the vehicle.
2. Turn ON the ignition, with the engine OFF.
3. Perform the 2-4 Brake Solenoid control with a scan tool.
4. Command the solenoid valve ON and OFF.
Does the 2-4 brake solenoid valve click with each
command? —
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

7A2-64 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P0763 (Flash Code 33)
Circuit Description
The high clutch solenoid valve controls fluid acting on
spool valves in the high clutch hydraulic circuits, which
then controls high clutch apply and release. The
solenoid valve is installed to the lower part of the valve
body assembly. The TCM controls the solenoid valve
by a duty cycle (pulse width modulation [PWM]) signal
based on the commanded gear position. The solenoid
valve provides a smooth gearshift by operating on a
duty cycle percentage of ON time. The TCM monitors
the high clutch solenoid valve operating status through
the feedback circuit. If the TCM detects an improper
voltage level on the control circuit, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects an open circuit or short circuit on the high clutch solenoid valve control circuit.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails.
During the vehicle running;
• The TCM holds the last gear position when the diagnostic runs and fails.
• The TCM stops high clutch solenoid valve. • The TCM inhibits lock up control.
After the vehicle stopped;
• The TCM stops all shift solenoid valves and fixes to the 3rd gear. If a fail-safe valve problem is
detected, the shift solenoid valves are not stopped
but gear is fixed to the 3rd gear.
• The TCM stops PC solenoid valve.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail at next
ignition cycle.
• A current DTC clears when the diagnostic runs and does not fail at next ignition cycle.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Use the Clutch, Brake, Solenoid and Pressure Switch Logic table to verify each component works
properly within the selected gear range.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0763
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check - Transmission Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Is DTC P1875 also set? —
Go to DTC P1875 Go to Step 3
3 1. Park the vehicle.
2. Turn ON the ignition, with the engine OFF.
3. Perform the High Clutch Solenoid control with a scan tool.
4. Command the solenoid valve ON and OFF.
Does the high clutch solenoid valve click with each
command? —
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-67
DTC P0768 (Flash Code 34)
Circuit Description
The low clutch solenoid valve controls fluid acting on
spool valves in the low clutch hydraulic circuits, which
then controls low clutch apply and release. The
solenoid valve is installed to the lower part of the valve
body assembly. The TCM controls the solenoid valve
by a duty cycle (pulse width modulation [PWM]) signal
based on the commanded gear position. The solenoid
valve provides a smooth gearshift by operating on a
duty cycle percentage of ON time. The TCM monitors
the low clutch solenoid valve operating status through
the feedback circuit. If the TCM detects an improper
voltage level on the control circuit, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects an open circuit or short circuit on the low clutch solenoid valve control circuit.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails.
During the vehicle running;
• The TCM holds the last gear position when the diagnostic runs and fails.
• The TCM stops low clutch solenoid valve. • The TCM inhibits lock up control.
After the vehicle stopped;
• The TCM stops all shift solenoid valves and fixes to the 3rd gear. If a fail-safe valve problem is
detected, the shift solenoid valves are not stopped
but gear is fixed to the 3rd gear.
• The TCM stops PC solenoid valve.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail at next
ignition cycle.
• A current DTC clears when the diagnostic runs and does not fail at next ignition cycle.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Use the Clutch, Brake, Solenoid and Pressure Switch Logic table to verify each component works
properly within the selected gear range.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0768
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check - Transmission Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Is DTC P1875 also set? —
Go to DTC P1875 Go to Step 3
3 1. Park the vehicle.
2. Turn ON the ignition, with the engine OFF.
3. Perform the Low Clutch Solenoid control with a scan tool.
4. Command the solenoid valve ON and OFF.
Does the low clutch solenoid valve click with each
command? —
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

7A2-70 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P1120 (Flash Code 22)
Circuit Description
The accelerator pedal position (APP) sensor is
mounted on the accelerator pedal control assembly.
The analogue APP signals are converted by the engine
control module (ECM) into a pulse width modulation
(PWM) signal. This converted signal is continually sent
from the ECM to the TCM to determine appropriate
shift points depending on the accelerator pedal
pressing amount. If the TCM fails to receive a PWM
signal from the ECM, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects that the APP PWM signal from the ECM is not being received.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails.
During the vehicle running; • The TCM holds the last gear position when the
diagnostic runs and fails.
• The TCM inhibits lock up control.
After the vehicle stopped;
• The TCM stops all shift solenoid valves and fixes to the 3rd gear. If a fail-safe valve problem is
detected, the shift solenoid valves are not stopped
but gear is fixed to the 3rd gear.
• The TCM stops PC solenoid valve.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail.
• A current DTC clears when the diagnostic runs and does not fail.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Circuit/ System Testing DTC P1120
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check - Transmission
Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Monitor the ENGINE DTC Information with a scan tool.
Is DTC P2621 or P2622 set? —
Go to Applicable DTC in engine
control section Go to Diagnostic
Aids

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-71
DTC P1750 (Flash Code 51)
Circuit Description
The low & reverse brake transmission fluid pressure
(TFP) switch is installed to the lower part of the valve
body assembly and it feedbacks fluid pressure in the
low & reverse brake hydraulic circuit. The low & reverse
brake fail-safe spool valves are installed to the control
valve body assembly and it uses to prevent interlocking
of clutches and brakes. When the solenoid valve is
energized, fluid pressure is drained to disengage the
low & reverse brake and the TFP switch is OFF. When
the solenoid valve is not energized, fluid pressure is
applied to engage the low & reverse brake and the TFP
switch is ON. The TCM monitors the low & reverse
brake TFP switch ON/ OFF status through the signal
circuit. If the TCM detects an improper status on the
signal circuit, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects that the low & reverse brake TFP switch signal repeats OFF/ ON twice when the
selector lever in forward range with the 2nd, 3rd or
4th gear.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails. During the vehicle running;
• The TCM holds the last gear position when the diagnostic runs and fails.
• The TCM inhibits lock up control.
After the vehicle stopped;
• The TCM fixes to the 3rd gear.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail at next
ignition cycle.
• A current DTC clears when the diagnostic runs and does not fail at next ignition cycle.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Use the Clutch, Brake, Solenoid and Pressure Switch Logic table to verify each component works
properly within the selected gear range.
• A sticking or intermittently sticking the low & reverse brake solenoid valve will cause this DTC to
set.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P1750
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Transmission Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Is DTC P0753 or P1853 also set? —
Go to Applicable DTC Go to Step 3
3 Place the selector lever in forward range while
observing the Low & Reverse Brake Pressure
Switch parameter with a scan tool.
Does the Low & Reverse Brake Pressure Switch
parameter ever indicate ON when gear is shifted
between 1st and 4th? —
Go to Step 4 Go to Diagnostic
Aids

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-73
DTC P1755 (Flash Code 52)
Circuit Description
The 2-4 brake transmission fluid pressure (TFP) switch
is installed to the lower part of the valve body assembly
and it feedbacks fluid pressure in the 2-4 brake
hydraulic circuit. The low & reverse brake fail-safe
spool valves are installed to the control valve body
assembly and it uses to prevent interlocking of clutches
and brakes. When the solenoid valve is energized, fluid
pressure is drained to disengage the 2-4 brake and the
TFP switch is OFF. When the solenoid valve is not
energized, fluid pressure is applied to engage the 2-4
brake and the TFP switch is ON. The TCM monitors the
2-4 brake TFP switch ON/ OFF status through the
signal circuit. If the TCM detects an improper status on
the signal circuit, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects that the 2-4 brake TFP switch signal repeats OFF/ ON twice when the selector
lever in forward range with the 3rd gear.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails. During the vehicle running;
• The TCM holds the last gear position when the diagnostic runs and fails.
• The TCM inhibits lock up control.
After the vehicle stopped;
• The TCM fixes to the 3rd gear.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail at next
ignition cycle.
• A current DTC clears when the diagnostic runs and does not fail at next ignition cycle.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Use the Clutch, Brake, Solenoid and Pressure Switch Logic table to verify each component works
properly within the selected gear range.
• A sticking or intermittently sticking the 2-4 brake solenoid valve will cause this DTC to set.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P1755
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Transmission Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Is DTC P0758or P1858 also set? —
Go to Applicable DTC Go to Step 3
3 Place the selector lever in forward range while
observing the 2-4 Brake Pressure Switch
parameter with a scan tool.
Does the 2-4 Brake Pressure Switch parameter
ever indicate ON when gear is positioned 1st and
3rd? —
Go to Step 4 Go to Diagnostic
Aids

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-81
DTC P1860 (Flash Code 36)
Circuit Description
The torque converter clutch (TCC) solenoid valve
controls fluid acting on the lock up control spool valve,
which then controls lock up clutch apply and release.
The solenoid valve is installed to the lower part of the
valve body assembly. The TCM controls the solenoid
valve by a duty cycle (pulse width modulation [PWM])
signal based on the vehicle running conditions. The
solenoid valve provides a smooth engagement of the
torque converter clutch by operating on a duty cycle
percentage of ON time. The TCM monitors the TCC
solenoid valve operating status through the feedback
circuit. If the TCM detects an improper voltage level on
the control circuit, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC • The TCM detects an open circuit or short circuit on the TCC solenoid valve control circuit. Action Taken When the DTC Sets
• The TCM blinks the Check Trans lamp when the diagnostic runs and fails.
• The TCM inhibits lock up control.
Condition for Clearing the DTC • The TCM turns OFF the Check Trans lamp when the diagnostic runs and does not fail at next
ignition cycle.
• A current DTC clears when the diagnostic runs and does not fail at next ignition cycle.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P1860
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Transmission Controls
2 1. Install a scan tool.
2. Perform the Torque Converter Clutch (TCC) Solenoid control with a scan tool.
3. Command the solenoid valve ON and OFF.
Does the TCC solenoid valve click with each
command? —
Go to Diagnostic Aids Go to Step 3
3 1. Turn OFF the ignition.
2. Disconnect the in-line harness connector (E- 54) near the transmission range switch.
3. Connect a test lamp between the control circuit (pin 4 of E-54 female side) and a known
good ground.
4. Turn ON the ignition, with the engine OFF.
5. Perform the TCC Solenoid control with a scan tool.
6. Command the solenoid valve ON and OFF.
Does the test lamp turn ON and OFF with each
command? —
Go to Step 8 Go to Step 4
4 Does the test lamp remain illuminated with each
command? —
Go to Step 5 Go to Step 6

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TO MODEL INDEX
ISUZU KB P190 2007