Circuit ISUZU KB P190 2007 Workshop Repair Manual

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

7A2-62 TRANSMISSION CONTROL SYSTEM (JR405E)
41. 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 9 of E-54 female side) and a known
good ground.
4. Turn ON the ignition, with the engine OFF.
5. Perform the 2-4 Brake 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 9 Go to Step 5
5 Does the test lamp remain illuminated with each
command? —
Go to Step 6 Go to Step 7
6 1. Test the control circuit between the TCM (pin 7
of C-95) and the in-line harness connector (pin
9 of E-54 female side) for a short to battery or
ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
7 1. Test the control circuit between the TCM (pin 7
of C-95) and the in-line harness connector (pin
9 of E-54 female side) for the following
conditions:
• An open circuit
• A short to ground
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 8
8 1. Turn OFF the ignition.
2. Disconnect the TCM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
TCM (pin 7 of C-95).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
9 1. Inspect for an intermittent and for a poor
connection at the in-line harness connector
(pin 9 of E-54).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 10
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-63
101. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect the 2-4 brake solenoid valve for the following conditions:
• Physical damage of solenoid valve
• Loose or improper installation of solenoid valve
3. Inspect for an intermittent and for a poor connection at the harness connector of the 2-
4 brake solenoid valve or in-line harness
connector.
4. Inspect for an intermittent and for a poor connection of ground wire.
5. Test the control circuit between the 2-4 brake solenoid valve and the in-line harness
connector (pin 9 of E-54 male side) for the
following conditions:
• An open circuit
• A short to ground
• A short to the other solenoid valve circuit
• High resistance
6. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 11
11 Replace the 2-4 brake solenoid valve. Refer to
repair instructions (On-Vehicle Service).
Did you complete the replacement? —
Go to Step 13 —
12 Important:
Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 13 —
13 1. Reconnect all previously disconnected
components or harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Did the DTC fail this ignition? —
Go to Step 4 Go to Step 14
14 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No

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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) 7A2-65
41. 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 10 of E-54 female side) and a
known good ground.
4. Turn ON the ignition, with the engine OFF.
5. Perform the High Clutch 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 9 Go to Step 5
5 Does the test lamp remain illuminated with each
command? —
Go to Step 6 Go to Step 7
6 1. Test the control circuit between the TCM (pin 8
of C-95) and the in-line harness connector (pin
10 of E-54 female side) for a short to battery
or ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
7 1. Test the control circuit between the TCM (pin 8
of C-95) and the in-line harness connector (pin
10 of E-54 female side) for the following
conditions:
• An open circuit
• A short to ground
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 8
8 1. Turn OFF the ignition.
2. Disconnect the TCM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
TCM (pin 8 of C-95).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
9 1. Inspect for an intermittent and for a poor
connection at the in-line harness connector
(pin 10 of E-54).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 10
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

7A2-66 TRANSMISSION CONTROL SYSTEM (JR405E)
101. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect the high clutch solenoid valve for the following conditions:
• Physical damage of solenoid valve
• Loose or improper installation of solenoid valve
3. Inspect for an intermittent and for a poor connection at the harness connector of the
high clutch solenoid valve or in-line harness
connector.
4. Inspect for an intermittent and for a poor connection of ground wire.
5. Test the control circuit between the high clutch solenoid valve and the in-line harness
connector (pin 10 of E-54 male side) for the
following conditions:
• An open circuit
• A short to ground
• A short to the other solenoid valve circuit
• High resistance
6. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 11
11 Replace the high clutch solenoid valve. Refer to
repair instructions (On-Vehicle Service).
Did you complete the replacement? —
Go to Step 13 —
12 Important:
Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 13 —
13 1. Reconnect all previously disconnected
components or harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Did the DTC fail this ignition? —
Go to Step 4 Go to Step 14
14 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No

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TO MODEL INDEX
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

7A2-68 TRANSMISSION CONTROL SYSTEM (JR405E)
41. 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 3 of E-54 female side) and a known
good ground.
4. Turn ON the ignition, with the engine OFF.
5. Perform the Low Clutch 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 9 Go to Step 5
5 Does the test lamp remain illuminated with each
command? —
Go to Step 6 Go to Step 7
6 1. Test the control circuit between the TCM (pin 9
of C-95) and the in-line harness connector (pin
3 of E-54 female side) for a short to battery or
ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
7 1. Test the control circuit between the TCM (pin 9
of C-95) and the in-line harness connector (pin
3 of E-54 female side) for the following
conditions:
• An open circuit
• A short to ground
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 8
8 1. Turn OFF the ignition.
2. Disconnect the TCM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
TCM (pin 9 of C-95).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
9 1. Inspect for an intermittent and for a poor
connection at the in-line harness connector
(pin 3 of E-54).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 10
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-69
101. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect the low clutch solenoid valve for the following conditions:
• Physical damage of solenoid valve
• Loose or improper installation of solenoid valve
3. Inspect for an intermittent and for a poor connection at the harness connector of the
low clutch solenoid valve or in-line harness
connector.
4. Inspect for an intermittent and for a poor connection of ground wire.
5. Test the control circuit between the low clutch solenoid valve and the in-line harness
connector (pin 3 of E-54 male side) for the
following conditions:
• An open circuit
• A short to ground
• A short to the other solenoid valve circuit
• High resistance
6. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 11
11 Replace the low clutch solenoid valve. Refer to
repair instructions (On-Vehicle Service).
Did you complete the replacement? —
Go to Step 13 —
12 Important:
Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 13 —
13 1. Reconnect all previously disconnected
components or harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Lift the driving wheels or drive the vehicle while observing the DTC Information with a
scan tool.
Did the DTC fail this ignition? —
Go to Step 4 Go to Step 14
14 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No

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TO MODEL INDEX
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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TO MODEL INDEX
ISUZU KB P190 2007