Circuit ISUZU KB P190 2007 Workshop Repair Manual

7A2-48 TRANSMISSION CONTROL SYSTEM (JR405E)
4Intermittently jump the signal circuit (pin 1 of E-30)
with a test lamp that is connected to a known good
ground while observing the AT Output Speed or
Vehicle Speed parameter with a scan tool.
Does the scan tool indicate any AT output speed or
vehicle speed when the circuit is intermittently
pulled to ground? —
Go to Step 5 Go to Step 8
5 Connect a test lamp between the ignition voltage
feed circuit and the low reference circuit (pins 2 and
3 of E-30).
Does the test lamp illuminate? —
Go to Step 9 Go to Step 7
6 Repair the open circuit or high resistance between
the TCM (15A) fuse and the OSS sensor (pin 2 of
E-30).
Did you complete the repair? —
Go to Step 14 —
7 Repair the open circuit or high resistance on the
low reference circuit between the OSS sensor (pin
3 of E-30) and the engine ground terminal (E-10).
Clean or tighten ground as necessary.
Did you complete the repair? —
Go to Step 14 —
8 1. Test the signal circuit between the TCM (pin
13 of C-95) and the OSS sensor (pin 1 of E-
30) for the following conditions:
• An open circuit
• A short to ground
• A short to the low reference
• A short to battery or ignition voltage
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 10
9 1. Inspect for an intermittent and for poor
connections at the harness connector of the
OSS sensor (pin 1, 2 and 3 of E-30).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 11
10 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 13 of C-95).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 13
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

7A2-50 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P0727 (Flash Code 13)
Circuit Description
The engine speed signal to the TCM is sent from the
engine control module (ECM) via a signal circuit based
on inputs from the crankshaft position (CKP) sensor
and camshaft position (CMP) sensor. If the TCM
detects no engine speed signal from the ECM during
the vehicle running, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
• The vehicle speed is more than 40 km/h (24 MPH).
Condition for Setting the DTC • The TCM detects that the engine speed signal pulses from the ECM are not being received for 2
seconds. 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.
• 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.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0727
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. If the engine does not start, crank over the engine for 10 seconds.
4. Monitor the ENGINE DTC Information with a scan tool.
Is DTC P0335, P0336, P0340 or P0341 set? —
Go to Applicable DTC in engine
control section Go to Step 3
3 Observe the Engine Speed parameter in the
transmission data display with a scan tool.
Does the scan tool indicate correct engine speed? —
Go to Diagnostic
Aids Go to Step 4
4 1. Turn OFF the ignition.
2. Disconnect the engine control module (ECM) harness connector.
3. Turn ON the ignition, with the engine OFF.
4. Intermittently jump the signal circuit (pin 33 of C-58) with a test lamp that is connected to a
known good ground while observing the
Engine Speed parameter with a scan tool.
Does the scan tool indicate any engine speed when
the circuit is intermittently pulled to ground? —
Go to Step 7 Go to Step 5

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-51
51. Test the signal circuit between the ECM (33 of
C-58) and the TCM (7 of C-94) for the
following conditions:
• An open circuit
• A short to ground
• A short to battery or ignition voltage
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 10 Go to Step 6
6 1. Turn OFF the ignition.
2. Inspect for an intermittent and for a poor connection at the harness connector of the
TCM (pin 7 of C-94).
3. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 10 Go to Step 8
7 1. Turn OFF the ignition.
2. Inspect for an intermittent and for a poor connection at the harness connector of the
ECM (pin 33 of C-58).
3. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 10 Go to Step 9
8 Important:
Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 10 —
9 Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 10 —
10 1. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Observe the Engine Speed parameter with a scan tool.
Does the scan tool indicate correct engine speed? —
Go to Step 11 Go to Step 4
11 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

7A2-52 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P0731, P0732, P0733 or P0734 (Flash Code 41, 42, 43 or 44)
Circuit Description
The TCM calculates the gear ratio based on the input
shaft speed signal from the input shaft speed (ISS)
sensor and the output speed signal from the output
shaft speed (OSS) sensor. The TCM compares the
known transmission gear ratio to the calculated ratio for
the selected gear ranges. If the TCM detects an
unknown transmission gear ratio two consecutive
driving cycles, this DTC will set.
Condition for Running the DTC • Other than DTCs P0731, P0732, P0733 and P0734 are not set.
• The ignition switch is ON.
• The transmission fluid temperature is more than 60 °C (140 °F).
• The input shaft speed is more than 1000 RPM.
• The vehicle speed is more than 10 km/h (6 MPH).
• The selector lever is forward range for longer than 2 seconds.
• The TCM is not under gearshift control.
Condition for Setting the DTC • The TCM detects that the output shaft speed is more than 500 RPM over the calculated speed
(based on the input shaft speed and the gear ratio)
for 7 seconds after each gearshift has completed.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp on the second consecutive driving cycle when the
diagnostic runs and fails.
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.
• Electromagnetic interference in the ISS sensor or OSS sensor circuits may set this DTC.
• An intermittent ISS sensor or OSS sensor signal pulse may set this DTC.
• Ensure the ISS sensor and OSS sensor is tight.
• Use the Clutch, Brake, Solenoid and Pressure Switch Logic table to verify each component works
properly within the selected gear range.
• A transmission mechanical problem will cause this DTC to set.
• Sticking or contamination of shift valves may cause intermittent incorrect gear ratios.
• If multiple incorrect gear ratio codes are set, problem in fluid pressure, low ATF level, plugged
filter or oil pump problem may exist.
Notice: • Each DTC agrees with the following gear positions.
- P0731: 1st gear
- P0732: 2nd gear
- P0733: 3rd gear
- P0734: 4th gear
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0731, P0732, P0733 or P0734
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 Perform the ATF level check. Refer to repair
instructions (On-Vehicle Service).
Did you perform the ATF level check? —
Go to Step 3 Go to Transmission
Fluid Checking Procedure
3 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Drive the vehicle while observing the DTC Information with a scan tool.
Is there any DTCs set other than P0731, P0732,
P0733 or P0734? —
Refer to Applicable DTC Go to Step 4

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-53
41. Inspect all of the circuits going to the input
shaft speed (ISS) sensor and the output shaft
speed (OSS) sensor for the following
conditions:
• Routed too closely to fuel injection wiring or components
• Routed too closely to after-market add- on electrical equipment
• Routed too closely to solenoids and relays
2. If you find incorrect routing, correct the harness routing.
Did you find and correct the condition? —
Go to Step 13 Go to Step 5
5 1. Disconnect the ISS sensor and the OSS
sensor harness connector.
2. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ISS sensor (pins 1, 2 and 3 of
E-31) and the OSS sensor (pins 1,2 and 3 of
E-30).
3. Disconnect the TCM harness connector.
4. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the TCM (pins 3 and 13 of C-95).
5. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 6
6 1. Inspect the ISS sensor and the OSS sensor
for the following conditions:
• Physical damage of sensor
• Loose or improper installation of sensor
• Excessive air gap
• Foreign material passing between ISS sensor and reverse & high clutch drum
• Foreign material passing between OSS sensor and parking gear
• Physical damage of reverse & high clutch drum or parking gear
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 7
7 1. Place the selector lever in D range.
2. Observe the Low & Reverse Brake Pressure Switch, 2-4 Brake Pressure Switch and High
Clutch Pressure Switch parameter with a scan
tool. Refer to Clutch, Brake, Solenoid and
Pressure Switch Logic table.
Does the each transmission fluid pressure (TFP)
switch display match each selected gear range? —
Go to Step 8 Refer to DTC
P1853, P1858 or P1863
8 Perform the line pressure test. Refer to Line
Pressure Test.
Is the line pressure within specifications for each
selected gear range? —
Go to Step 9 Refer to appropriate
instructions in the
Line Pressure Test
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-55
DTC P0748 (Flash Code 35)
Circuit Description
The pressure control (PC) solenoid valve is installed to
the lower part of the valve body assembly. It controls
the transmission fluid supply to the pressure regulator
spool valve in the valve body. The TCM controls the
solenoid valve by ON/ OFF signal based on the vehicle
running conditions. The TCM turns ON the solenoid
valve when a lower line pressure is required and turns
OFF when a higher line pressure is required. With the
operation of this solenoid valve, the operation and shift
of the hydraulic circuit in the transmission can be
performed smoothly. The PC solenoid valve is
controlled according to the range position, speed
sensor signals, transmission fluid temperature signal
and the accelerator pedal position signal. The TCM
monitors the PC 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 PC 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 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.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0748
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 Pressure Control (PC) Solenoid control with a scan tool.
3. Command the solenoid valve ON and OFF.
Does the PC 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 6 of E-54 female side) and a known
good ground.
4. Turn ON the ignition, with the engine OFF.
5. Perform the PC 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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ISUZU KB P190 2007

7A2-56 TRANSMISSION CONTROL SYSTEM (JR405E)
51. Test the control circuit between the TCM (pin
23 of C-95) and the in-line harness connector
(pin 6 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 12 Go to Step 11
6 1. Test the control circuit between the TCM (pin
23 of C-95) and the in-line harness connector
(pin 6 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 12 Go to Step 7
7 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 23 of C-95).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 11
8 1. Inspect for an intermittent and for a poor
connection at the in-line harness connector
(pin 6 of E-54).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 9
9 1. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect the PC 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 in-line harness connector.
4. Test the control circuit between the PC solenoid valve and the in-line harness
connector (pin 6 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
5. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 10
10 Replace the PC solenoid valve. Refer to repair
instructions (On-Vehicle Service).
Did you complete the replacement? —
Go to Step 12 —
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

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) 7A2-59
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 5 of E-54 female side) and a known
good ground.
4. Turn ON the ignition, with the engine OFF.
5. Perform the Low & Reverse 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 6
of C-95) and the in-line harness connector (pin
5 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 6
of C-95) and the in-line harness connector (pin
5 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 6 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 5 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

7A2-60 TRANSMISSION CONTROL SYSTEM (JR405E)
101. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect the low & reverse 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
low & reverse 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 low & reverse brake solenoid valve and the in-line
harness connector (pin 5 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 & reverse 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