relay ISUZU KB P190 2007 Workshop Repair Manual

6E-166 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P0404 (Flash Code 45)
Circuit Description
The ECM controls the EGR valve opening based on the
engine running condition and by controlling the EGR
solenoid. The EGR valve position is detected by the
position sensor, and relayed to the ECM. If the ECM
detects a variance between the actual EGR valve
position and desired EGR valve position for a
calibrated amount of time while the EGR valve is
commanded ON, this DTC will set.
Condition for Running the DTC • DTCs P0112, P0113, P0116, P0117, P0118, P0405, P0406, P0652, P0653, P2227, P2228 and
P2229 are not set.
• The battery voltage is between 10 to 16 volts.
• The ignition switch is ON.
• The engine coolant temperature is between 20 to 11 0 °C (68 to 230 °F).
• The intake air temperature is between 0 to 110 °C
(32 to 230 °F).
• The barometric pressure is between 60 to 120 kPa (8.7 to 17.4 psi).
• The EGR control is commanded ON. Condition for Setting the DTC
• The ECM detects that the actual EGR position is more than 10% below the desired position for 4
seconds.
Action Taken When the DTC Sets • The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM limits fuel injection quantity.
• The ECM inhibits pilot injection.
• The ECM inhibits EGR control.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• A sticking or intermittently sticking EGR valve may set this DTC.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0404
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine 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.
Is DTC P0403, P0405 or P0406 also set? —
Go to Applicable DTC Go to Step 3
3 1. Perform the EGR Solenoid Control with a scan
tool several times.
2. Command the Desired EGR Position Increase and Decrease while observing the EGR
Position.
Does the EGR Position parameter follow within the
specified value quick enough (compare with a
similar unit if available)?
± 5%
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

6E-176 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P0501 (Flash Code 25)
Circuit Description
The vehicle speed sensor (VSS) is used by the ECM
and speedometer, which generates a speed signal from
the transmission output shaft rotational speed or
transfer output shaft rotational speed. The sensor has
the following circuits.
• Ignition voltage feed circuit
• Low reference circuit
• VSS signal circuit
The VSS uses a hall effect element. It interacts with the
magnetic field created by the rotating magnet and
outputs square wave pulse signal. The ECM calculates
the vehicle speed by the VSS. If the 2WD fitted with
Jatco automatic transmission, VSS signals are sent
from the TCM. If the ECM detects VSS signals are
sharply changed, this DTC will set.
Condition for Running the DTC • The ignition voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects that the VSS signal are changed larger than a predetermined vehicle speed within a
very short calibrated time. Action Taken When the DTC Sets
• The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Electromagnetic interference in the VSS circuits may set this DTC.
Notice: • If this DTC set, the Vehicle Speed parameter on the scan tool will display 3 km/h (2 MPH).
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0501
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 1. Inspect all of the circuits going to the vehicle
speed sensor (VSS) 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, relays, and motors
2. If you find incorrect routing, correct the harness routing.
Did you find and correct the condition? —
Go to Step 8 Go to Step 3
3 1. Inspect for an intermittent, for poor
connections and corrosion at the Meter (10A)
fuse.
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 4
4 1. Inspect for an intermittent, a poor connection
and corrosion at the ground terminal (E-10).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 5

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ISUZU KB P190 2007

6E-178 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P0512 (Flash Code 417)
Circuit Description
The starter switch signal is inputted to the ECM during
the ignition switch START position. If the ECM detects
the starter switch signal continuously ON during the
engine running, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
• The engine is running.
Condition for Setting the DTC • The ECM detects that the starter switch signal is stuck at the ON position (high voltage) for longer
than 20 seconds.
Action Taken When the DTC Sets • The ECM illuminates the SVS lamp when the diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C. Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for Clearing the SVS Lamp/ DTC - Type C.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Notice: • This DTC will set if the ignition switch continues being START position for longer than 20 seconds.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0512
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 1. Turn OFF the ignition.
2. Remove the starter cut relay in order to inhibit starter motor engagement at ignition switch
ON.
3. Install a scan tool.
4. Turn ON the ignition, with the engine OFF.
5. Observe the Starter Switch parameter with a scan tool.
Does the Starter Switch parameter indicate OFF? —
Go to Diagnostic Aids Go to Step 3
3 Remove the Starter (10A) fuse in the cabin fuse
block.
Does the Starter Switch parameter indicate OFF? —
Go to Step 4 Go to Step 5
4 1. Test the signal circuit between the starter
switch (pin 1 of B-63) and each terminal of the
ignition switch (pins 1, 2, 3 and 4 of B-62 and
pin 3 of B-63) for short circuit each other at the
ignition switch ON.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 7
5 1. Test the signal circuit between the ECM (pin
44 of C-58) and the Starter (10A) fuse or
starter relay (pin 3 of X-8) 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 8 Go to Step 6

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-179
61. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect the connection on the starter switch signal circuit at the harness connector of the
ECM (pin 44 of C-58) for corrosion.
4. Repair the connection(s) as necessary.
Did you complete the action? —
Go to Step 8
—
7Repair or replace the ignition switch.
Did you complete the repair or replacement? —
Go to Step 8—
81. Reconnect all previously disconnected relay
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. Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition? —
Go to Step 2 Go to Step 9
9 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

6E-198 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P0615 (Flash Code 19)
Circuit Description
The ECM controls the starter cut relay, which de-
energizes the starter relay based on engine speed
inputs or immobilizer command signal. The starter cut
relay uses normally close type relay. During engine
stopping, the starter cut relay is closed to allow
grounding the starter relay. Once engine run, the ECM
energizes the starter cut relay to open the starter relay
circuit and starter motor is disengaged even the ignition
is positioned at START. If the ECM detects an improper
voltage on the starter cut relay control circuit, this DTC
will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC
Either of following condition is met: • The ECM detects a short to ground circuit condition on the starter cut relay control circuit for
longer than 3 seconds when the relay is
commanded OFF. • The ECM detects a short to voltage circuit
condition on the starter cut relay control circuit for
longer than 3 seconds when the relay is
commanded ON.
Action Taken When the DTC Sets • The ECM illuminates the SVS lamp when the diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Typ e C.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the SVS Lamp/ DTC - Type C.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Notice: • If the starter cut relay control circuit is short to ground, engine does not crank.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0615
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF. DO NOT start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 4 Go to Step 3
3 1. Start the engine.
2. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 6 Go to Diagnostic
Aids
4 1. Turn OFF the ignition.
2. Replace the starter cut relay with the head light dimmer relay or replace with a known
good relay.
3. Turn ON the ignition, with the engine OFF. DO NOT start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 5 Go to Step 7

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-199
51. Test the control circuit between the ECM (pin
35 of C-58) and the relay (pin 3 of X-7) for a
short to ground.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 9 Go to Step 8
6 1. Test the control circuit between the ECM (pin
35 of C-58) and the relay (pin 3 of X-7) 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 9 Go to Step 8
7 Replace the starter cut relay.
Did you complete the replacement? —
Go to Step 9
—
8Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 9
—
91. Reconnect all previously disconnected relay
or harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Turn ON the ignition for 10 seconds.
5. Start the engine.
Did the DTC fail this ignition? —
Go to Step 2 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

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-201
DTC P0638 (Flash Code 61)
Circuit Description
The ECM controls the intake throttle valve opening
based on the engine running condition and by
controlling the intake throttle solenoid. The intake
throttle valve position is detected by the position
sensor, and relayed to the ECM. If the ECM detects a
variance between the actual intake throttle position and
desired intake throttle position while the intake throttle
solenoid is commanded ON, this DTC will set.
Condition for Running the DTC • DTCs P0122, P0123, P0698 and P0699 are not set.
• The battery voltage is between 11 to 16 volts.
• The ignition switch is ON.
• The intake throttle solenoid commanded ON.
• The desired intake throttle position is stable.
Condition for Setting the DTC • The ECM detects that the difference between the actual and the desired intake throttle position is
more than 10% for 5 seconds. Action Taken When the DTC Sets
• The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM limits fuel injection quantity.
• The ECM inhibits pilot injection.
• The ECM inhibits EGR control.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• A sticking or intermittently sticking intake throttle valve may set this DTC.
• A sticking intake throttle valve at full closed position will cause engine starting problem.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0638
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine 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.
Is DTC P0122, P0123, P2100, P2101 or P2103
also set? —
Go to Applicable DTC Go to Step 3
3 1. Perform the Intake Throttle Solenoid Control
with a scan tool several times.
2. Command the Desired Intake Throttle Position Increase and Decrease while observing the
Intake Throttle Position.
Does the Intake Throttle Position parameter follow
within the specified value quick enough (compare
with a similar unit if available)? ±
5%
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-237
DTC P1196, P1197 or P1198 (Flash Code 461)
Circuit Description
The ECM controls the intake throttle valve opening
based on the engine running condition and by
controlling the intake throttle solenoid. The intake
throttle valve position is detected by the position
sensor, and relayed to the ECM. If the ECM detects an
excessively high temperature condition in its internal
intake throttle solenoid drive circuit for certain length of
time, DTC P1196, P1197 or P1198 will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects an excessively high temperature in its internal intake throttle solenoid drive circuit
for longer than 30 seconds. (DTC P1196)
• The ECM detects an excessively high temperature in its internal intake throttle solenoid drive circuit
for longer than 60 seconds in accumulation time
during same ignition cycle. (DTC P1197) • The ECM detects an excessively high temperature
in its internal intake throttle solenoid drive circuit
for longer than 120 seconds in accumulation time
exceeding ignition cycle. (DTC P1198)
Action Taken When the DTC Sets • The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM limits fuel injection quantity.
• The ECM inhibits pilot injection.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• A sticking or intermittently sticking intake throttle valve may set this DTC.
Circuit/ System Testing DTC P1196, P1197 or P1198
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine 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.
Is DTC P0638 also set? —
Go to DTC P0638 Go to Step 3
3 1. Perform the Intake Throttle Solenoid Control
with a scan tool several times.
2. Command the Desired Intake Throttle Position Increase and Decrease while observing the
Intake Throttle Position.
Does the Intake Throttle Position parameter follow
within the specified value quick enough (compare
with a similar unit if available)? ±
5%
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-243
31. Inspect for an intermittent, for poor tightening
and corrosion at the engine ground terminal
(E-10).
2. Repair the tightening or clean the corrosion as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 4
4 1. Test ground circuit between the ECM (pin 73
of E-90) and the engine ground terminal (E-
10) for an intermittently open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 5
5 1. Test the battery voltage feed circuit between
the ECM (pin 73 of E-90) and the ECM main
relay (pin 1 of X-12) for an intermittently open
circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 6
6 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pin 73 of C-58 and pin
73 of E-90).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 7
7 Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 8
—
81. Reconnect all previously disconnected relay
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. Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition? —
Go to Step 3 Go to Step 9
9 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

6E-244 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P1262 (Flash Code 34)
Circuit Description
The charge up circuit in the ECM steps up the voltage
for fuel injectors and is divided into two banks, common
1 and common 2. The common 1 covers fuel injectors
in cylinders #1 and #4, and the common 2 covers fuel
injectors in cylinders #2 and #3. If the common 2 fuel
injector charge up circuit in the ECM is an insufficient
charge or an overcharge, this DTC will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
• The engine is not running.
Condition for Setting the DTC • The ECM detects that the common 2 fuel injector charge up circuit is an insufficient charge or an
overcharge. Action Taken When the DTC Sets
• The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM limits fuel injection quantity.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P1262
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine 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 Step 8
3 1. Inspect for an intermittent, for poor tightening
and corrosion at the engine ground terminal
(E-10).
2. Repair the tightening or clean the corrosion as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 4
4 1. Test ground circuit between the ECM (pin 73
of E-90) and the engine ground terminal (E-
10) for an intermittently open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 5
5 1. Test the battery voltage feed circuit between
the ECM (pin 73 of E-90) and the ECM main
relay (pin 1 of X-12) for an intermittently open
circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 6

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ISUZU KB P190 2007