Isuzu KB P190. Manual — part 1086
7A2-60 TRANSMISSION CONTROL SYSTEM (JR405E)
10
1.
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
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
7A2-62 TRANSMISSION CONTROL SYSTEM (JR405E)
4
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 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
TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-63
10
1.
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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