2007 ISUZU KB P190 ECO mode

7A2-78 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P1858 (Flash Code 27)
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. 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 pressure 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 • DTCs P0560, P0705, P0717, P0722, P0753, P0758, P0763, P0768, P1120, P1750, P1755 and
P1875 are not set.
AND following conditions are met for longer than 2.5
seconds.
• The ignition switch is ON.
• The transmission fluid temperature is more than 60 °C (140 °F).
• The engine speed is more than 500 RPM.
• The TCM is not under gearshift control.
Condition for Setting the DTC
Either of following condition is met: • The TCM detects that the 2-4 brake TFP switch signal is stuck at the ON for longer than 2 seconds
when the selector lever in P, R or N range. • The TCM detects that the 2-4 brake TFP switch
signal is stuck at the OFF for longer than 2 second
when the selector lever in D range with 4th gear.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp 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.
• 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 P1858
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 P0758 also set? —
Go to DTC P0758 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 OFF when gear is positioned 2nd and
4th? —
Go to Step 5 Go to Step 4

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ISUZU KB P190 2007

7A2-80 TRANSMISSION CONTROL SYSTEM (JR405E)
91. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect the 2-4 brake solenoid valve and transmission fluid pressure (TFP) switch for
the following conditions:
• Physical damage
• Loose or improper installation
3. Inspect for an intermittent and for a poor connection at the harness connector of the 2-
4 brake TFP switch or in-line harness
connector.
4. Test the signal circuit between the 2-4 brake TFP switch and the in-line harness connector
(pin 7 of E-54 male side) for the following
conditions:
• An open circuit
• A short to ground
• A short to the solenoid valve circuit
• High resistance
5. Repair the connection(s), circuit(s) or replace as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 10
10 1. Remove the 2-4 brake solenoid valve and TFP
switch from the valve body assembly and
perform function check. Refer to repair
instructions (On-Vehicle Service).
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 11
11 Repair or replace the valve body assembly. Refer
to repair instructions (On-Vehicle Service or Unit
Repair).
Did you complete the repair or 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. Drive the vehicle while observing the DTC Information with a scan tool.
Did the DTC fail this ignition? —
Go to Step 2 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

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-83
10Replace the TCC solenoid valve. Refer to repair
instructions (On-Vehicle Service).
Did you complete the replacement? —
Go to Step 12 —
11 Important:
Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 12 —
12 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. Drive the vehicle while observing the DTC Information with a scan tool.
Did the DTC fail this ignition? —
Go to Step 3 Go to Step 13
13 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

7A2-84 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P1863 (Flash Code 28)
Circuit Description
The high clutch transmission fluid pressure (TFP)
switch is installed to the lower part of the valve body
assembly and it feedbacks fluid pressure in the high
clutch hydraulic circuit. When the solenoid valve is
energized, fluid pressure is drained to disengage the
high clutch and the TFP switch is OFF. When the
solenoid valve is not energized, fluid pressure is
applied to engage the high clutch and the TFP switch is
ON. The TCM monitors the high clutch 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 • DTCs P0560, P0705, P0717, P0722, P0753, P0758, P0763, P0768, P1120, P1750, P1755 and
P1875 are not set.
AND following conditions are met for longer than 3
seconds.
• The ignition switch is ON.
• The transmission fluid temperature is more than 60 °C (140 °F).
• The engine speed is more than 500 RPM.
• The TCM is not under gearshift control.
Condition for Setting the DTC
Either of following condition is met: • The TCM detects that the high clutch TFP switch
signal is stuck at the ON for longer than 2 seconds
when the selector lever in P, R or N range.
• The TCM detects that the high clutch TFP switch signal is stuck at the OFF for longer than 2 second
when the selector lever in D range with 4th gear.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp 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.
• 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 high clutch 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 P1863
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 P0763 also set? —
Go to DTC P0763 Go to Step 3
3 Place the selector lever in forward range while
observing the High Clutch Pressure Switch
parameter with a scan tool.
Does the High Clutch Pressure Switch parameter
ever indicate OFF when gear is positioned 3rd and
4th? —
Go to Step 5 Go to Step 4

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ISUZU KB P190 2007

7A2-86 TRANSMISSION CONTROL SYSTEM (JR405E)
91. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect the high clutch solenoid valve and transmission fluid pressure (TFP) switch for
the following conditions:
• Physical damage
• Loose or improper installation
3. Inspect for an intermittent and for a poor connection at the harness connector of the
high clutch TFP switch or in-line harness
connector.
4. Test the signal circuit between the high clutch TFP switch and the in-line harness connector
(pin 1 of E-54 male side) for the following
conditions:
• An open circuit
• A short to ground
• A short to the solenoid valve circuit
• High resistance
5. Repair the connection(s), circuit(s) or replace as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 10
10 1. Remove the high clutch solenoid valve and
TFP switch from the valve body assembly and
perform function check. Refer to repair
instructions (On-Vehicle Service).
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 11
11 Repair or replace the valve body assembly. Refer
to repair instructions (On-Vehicle Service or Unit
Repair).
Did you complete the repair or 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. Drive the vehicle while observing the DTC Information with a scan tool.
Did the DTC fail this ignition? —
Go to Step 2 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

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-87
DTC P1875 (Flash Code 25)
Circuit Description
The all shift solenoid valves feed drive voltage from the
TCM and low side circuit is connected to the TCM
through the ground return circuit. The TCM monitors
the ground return circuit through the feedback circuit. If
the TCM detects an improper status on the ground
return 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 on the ground return circuit.
Action Taken When the DTC Sets • The TCM blinks the Check Trans lamp when the diagnostic runs and fails.
• 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.
• 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 P1875
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 DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids
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 ground return circuit (pin 11 of E-54 male side) and
battery voltage.
Does the test lamp illuminate? —
Go to Step 4 Go to Step 7
4 1. Inspect for an intermittent and for a poor
connection at the in-line harness connector
(pin 11 of E-54).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 9 Go to Step 5
5 1. Test the circuit between the TCM (pin 22 of C-
95) and the in-line harness connector (pin 11
of E-54 female side) for an open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 9 Go to Step 6

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ISUZU KB P190 2007

7A2-88 TRANSMISSION CONTROL SYSTEM (JR405E)
61. 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 22 of C-95).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 9 Go to Step 8
7 1. Remove the transmission oil pan. Refer to
repair instructions (On-Vehicle Service).
2. Inspect for an intermittent and for a poor connection at the ground terminal or in-line
harness connector. Clean or tighten grounds
as necessary.
3. Repair the open circuit or high between the ground terminal and the in-line harness
connector (pin 11 of E-54 male side).
Did you complete the repair? —
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 9 —
9 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.
Did the DTC fail this ignition? —
Go to Step 3 Go to Step 10
10 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

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-89
Check Trans Lamp Inoperative, Always On or Always Blinking
Circuit Description
The Check Trans Lamp is located on the instrument
panel (IP) cluster. The Check Trans Lamp informs the
driver that a transmission control system fault has
occurred and that system requires service. The ignition
voltage is supplied to the Check Trans Lamp via meter
fuse. The TCM turns ON by grounding the lamp control
circuit. Check Trans Lamp Illumination
• The Check Trans Lamp illuminates for approximately 3 seconds when the ignition switch
is turned ON, with the engine OFF.
• The Check Trans Lamp blinks if the TCM detects a fault.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing Check Trans Lamp Inoperative, Always On or Always Blinking
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. Verify whether the instrument panel (IP)
cluster is operational.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
Does the check trans lamp turn ON then turn OFF
after 3 seconds passed? —
Go to Intermittent Conditions Go to Step 3
3 Does the check trans lamp blink?
—Check for DTCs and
if none exist Go to
Step 4 Go to Step 6
4 1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Observe the Diagnostic Switch parameter with a scan tool.
Does the Diagnostic Switch parameter indicate
ON? —
Go to Step 5 Check for DTCs
5 Repair the short to ground between the TCM (pin
18 of C-94) and the data link connector (DLC) (pin
11 o f B - 5 8 ) .
Did you complete the repair? —
Go to Step 21 —
6 1. Perform the Check Light control with a scan
tool.
2. Command the lamp ON and OFF.
Does the check trans lamp turn ON and OFF with
each command? —
Go to Intermittent Conditions Go to Step 7
7 1. Turn OFF the ignition.
2. Inspect the Meter (10A) fuse in the cabin fuse block.
Is the Meter (10A) fuse open? —
Go to Step 8 Go to Step 9

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ISUZU KB P190 2007