2007 ISUZU KB P190 Circuit

6E-302 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
EGR Control System Check
Description
The EGR system recirculates a part of exhaust gas
back into the intake manifold, which results in reducing
NOx emissions. The EGR control system uses an
electronic control system to ensure both driveability
and low emission. A control current from the ECM
operates a solenoid to control the lift amount of EGR
valve. Also, an EGR position sensor is provided at the
rear of the solenoid to feed actual valve lift amount
back to the ECM for more precision control.
The EGR control starts when the conditions for engine
speed, engine coolant temperature, intake air
temperature and barometric pressure are satisfied.
Then, the valve opening is calculated according to the
engine speed, and target fuel injection quantity. Based
on this valve opening, the drive duty of the solenoid is
determined and the valve is driven accordingly. The
intake throttle valve is provided to adequate intake
manifold depression to ensure EGR gas flow. EGR Control Operation
• The engine coolant temperature (ECT) is between 5°C (41 °F) and 100 °C (212 °F).
• The intake air temperature (IAT) is more than 5 °C
(41 °F).
• The barometric pressure (BARO) is more than 90kPa (13psi).
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing EGR Control System Check
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.
4. Monitor the DTC Information with a scan tool.
Are any DTCs set in which the “Action Taken When
the DTC Sets” under that particular code states,
“The ECM inhibits EGR control”? —
Refer to Applicable DTC Go to Step 3

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ISUZU KB P190 2007

6E-304 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
6Notice:
If the intake throttle solenoid is
commanded OFF, Intake Throttle Position
parameter indicates over 100%.
Observe the Desired Intake Throttle Position and
Intake Throttle Position parameter with a scan tool.
Does the Intake Throttle Position parameter follow
within the specified value? ±
5%
Go to Step 7 Go to Step 10
7 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? ±
5%
System OK Go to Step 10
8 1. Remove the EGR valve assembly from the
engine.
2. Inspect the EGR valve for the following conditions:
• Restricted EGR valve by foreign materials
• Excessive deposits at valve
• Bent valve shaft
3. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 9
9 1. Turn OFF the ignition.
2. Disconnect the EGR valve harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the EGR valve (pins 1, 2, 3, 4
and 6 of E-71).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 30, 31, 32, 62 and
63 of E-90).
6. Test for high resistance on each circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 12
10 1. Remove the intake duct that is connected to
the intake throttle valve.
2. Inspect the intake throttle valve for the following conditions:
• Restricted intake throttle valve by foreign materials
• Excessive deposits at throttle bore
• Bent butterfly valve
Notice: Replace the intake throttle valve is there is
any sticking
3. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 11
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-305
111. Turn OFF the ignition.
2. Disconnect the intake throttle valve harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the intake throttle valve (pins 1,
2, 3, 5 and 6 of E-38).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 35, 36, 55, 56 and
57 of E-90).
6. Test for high resistance on each circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 13
12 Replace the EGR valve. Refer to EGR valve
Replacement.
Did you complete the replacement? —
Go to Step 14
—
13Replace the intake throttle valve. Refer to Intake
Throttle Valve Replacement.
Did you complete the replacement? —
Go to Step 14
—
14Reconnect all previously disconnected components
or harness connector(s).
Did you complete the action? —
Go to Step 2
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

6E-306 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Glow Control System Check
Description
The glow control system consists of the ECM, the glow
relay, the glow indicator lamp and glow plugs. The glow
control system is operated when the engine coolant
temperature is low, which allows easier engine starting.
The ECM commands the glow relay ON for a certain
length of time at ignition switch is ON with engine OFF.
In after glow phase, the glow plugs remain energized
for a certain period with engine run.
Glow Control Operation • The glow indicator lamp illuminates between 0.5 seconds to 7 seconds depending upon the engine
coolant temperature. • The pre glow control system operates when the
engine coolant temperature is less than 30 °C
(86 °F).
• The after glow control system operates when the engine coolant temperature is less than 60 °C
(140 °F).
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Glow Control System Check (1 of 2)
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.
4. Monitor the DTC Information with a scan tool.
Is DTC P0117, P0118 or P0380 set? —
Refer to Applicable DTC Go to Step 3
3 Notice:
If no glow indicator lamp is equipped, skip
to Step 3.
1. Verify whether the instrument panel (IP) cluster is operational.
2. Perform the Glow Plug Lamp Control with a scan tool.
3. Command the lamp ON and OFF.
Does the glow indicator lamp turn ON and OFF
with each command? —
Go to Step 4 Go to 2 of 2 Step 1
4 1. Turn OFF the ignition.
2. Make sure the metal bus bar that connects switched battery voltage supply terminal (E-
49) and all glow plugs is secured tightly.
3. Turn ON the ignition, with the engine OFF
4. Connect a test lamp between the metal bus bar (glow plug power supply E-49 terminal)
and a known good ground.
5. Perform the Glow Relay Control with a scan tool.
6. Command the relay ON while observing the test lamp.
Does the test lamp turn ON only when commanded
ON? —
Go to Step 5 Go to Step 6

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-307
51. Turn OFF the ignition.
2. Remove the metal bus bar from the glow plugs.
3. Measure resistance of each glow plug between the glow plug terminals and a known
good ground. Make sure to record all
measurements and take them quickly as to
not allow engine temperature changes
between measurements.
Are the resistances within the specified value each
other? 1
Ω
System OK Go to Step 16
6 1. Turn OFF the ignition.
2. Replace the glow relay with the starter relay or replace with a known good relay.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the metal bus bar (glow plug power supply E-49 connector)
and a known good ground.
5. Perform the Glow Relay Control with a scan tool.
6. Command the relay ON while observing the test lamp.
Does the test lamp turn ON only when commanded
ON? —
Go to Step 14 Go to Step 7
7 Inspect the Glow (60A) slow blow fuse in the
engine room fuse block.
Is the Glow (60A) slow blow fuse open? —
Go to Step 8 Go to Step 9
8 Replace the Glow (60A) slow blow fuse. If the slow
blow fuse continues to open, repair the short to
ground on a circuit fed by the slow blow fuse or
check for a shorted attached component.
Did you complete the repair? —
Go to Step 17
—
91. Turn OFF the ignition.
2. Remove the glow relay.
3. Probe the battery voltage feed circuit of the relay (pin 4 of X-5) with a test lamp that is
connected to a known good ground.
Does the test lamp illuminate? —
Go to Step 10 Go to Step 11
10 1. Probe the voltage supply circuit of glow plugs
(pin 1 of X-5) with a test lamp that is
connected to a known good ground.
2. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate? —
Go to Step 13 Go to Step 12
11 Repair the open circuit or high resistance between
the Glow (60A) slow blow fuse and the glow relay
(pin 4 of X-5).
Did you complete the repair? —
Go to Step 17
—
12Repair the open circuit or high resistance between
the glow relay (pin 1 of X-5) and the glow plugs (E-
49 terminal).
Did you complete the repair? —
Go to Step 17
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

6E-308 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Circuit/ System Testing Glow Control System Check (2 of 2)
13Important
: The glow plugs may be burnt out if the
battery voltage supply circuit is shorted to a voltage
source.
Repair the short to battery or ignition voltage
between the glow relay (pin 1 of X-5) and the glow
plugs (E-49 terminal).
Did you complete the repair? —
Go to Step 17
—
141. Remove the glow relay.
2. Inspect for an intermittent and for poor connection on each glow relay terminal.
3. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 17 Go to Step 15
15 Replace the glow relay.
Did you complete the replacement? —
Go to Step 17
—
16Replace the appropriate glow plug.
Did you complete the replacement? —
Go to Step 17—
171. Reconnect all previously disconnected
components, relay, fuse or harness
connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the metal bus bar (glow plug power supply E-49 connector)
and a known good ground.
5. Perform the Glow Relay Control with a scan tool.
6. Command the relay ON while observing the test lamp.
Does the test lamp turn ON only when commanded
ON? —
Go to Step 5 Go to Step 2
Step
Action Value(s)Yes No
Step Action Value(s)Yes No
1 1. Turn OFF the ignition.
2. Inspect the Meter (10A) fuse in cabin fuse block.
Is the Meter (10A) fuse open? —
Go to Step 2 Go to Step 3
2 Replace the Meter (10A) fuse. If the fuse continues
to open, repair the short to ground on one of the
circuits that is fed by the Meter (10A) fuse or
replace the shorted attached component.
Did you complete the repair? —
Go to Step 14
—
31. Turn OFF the ignition.
2. Disconnect the ECM J-2 (C-58) harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the glow indicator lamp OFF? —
Go to Step 4 Go to Step 10

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-309
41. Remove the Meter (10A) fuse that supplies
voltage to the glow indicator lamp.
2. Turn ON the ignition, with the engine OFF.
3. Measure the voltage from the glow indicator lamp control circuit in the ECM harness
connector (pin 51 of C-58) to a known good
ground.
Is the voltage less than the specified value? 1 volt
Go to Step 5 Go to Step 11
5 1. Turn OFF the ignition.
2. Reinstall the Meter (10A) fuse.
3. Turn ON the ignition, with the engine OFF.
4. Connect a 3-amp fused jumper wire between the ECM harness connector (pin 51 of C-58)
and a known good ground.
Is the glow indicator lamp illuminated? —
Go to Step 9 Go to Step 6
6 1. Turn OFF the ignition.
2. Remove the IP cluster.
3. Connect a test lamp between the ignition voltage feed circuit of the IP cluster harness
connector (pin 8 of B-24) and a known good
ground.
Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate? —
Go to Step 7 Go to Step 12
7 1. Test the control circuit between the ECM (pin
51 of C-58) and the IP cluster (pin 35 of B-23)
for an open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 8
8 1. Inspect for an intermittent and for poor
connections at the harness connector of the
IP cluster (pin 35 of B-23 and pin 8 of B-24).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 13
9 1. Inspect for an intermittent and for a poor
connection at the harness connector of the
ECM (pin 51 of C-58).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 14
10 Repair the short to ground between the ECM (pin
51 of C-58) and the IP cluster (pin 35 or of B-23).
Did you complete the repair? —
Go to Step 15
—
11Repair the short to battery or ignition voltage
between the ECM (pin 51 of C-58) and the IP
cluster (pin 35 of B-23).
Did you complete the repair? —
Go to Step 15
—
12Repair the open circuit or high resistance on
ignition the voltage feed circuit the Meter (10A) fuse
and the IP cluster (pin 8 of B-24).
Did you complete the repair? —
Go to Step 15
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-311
In-Tank Fuel Pump System Check
Description
The ECM controls the fuel pump relay, which supplies
power to the fuel pump in the fuel tank. The ECM
commands the fuel pump relay ON for a certain length
of time at ignition switch is ON with the engine OFF.
During the engine is running it is continuity commanded
ON.
In-tank Fuel Pump Control Operation • The battery voltage is more than 9 volts. • The ignition switch is ON.
• The fuel pump is commanded ON for 12 seconds at ignition switch is ON with the engine OFF.
• The fuel pump is continuously ON while engine is running.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing In-Tank Fuel Pump System Check
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 for 20 seconds, then start the engine.
4. Monitor the DTC Information with a scan tool.
Is DTC P0231 or P0232 set? —
Refer to Applicable DTC Go to Step 3
3 1. Turn OFF the ignition for 30 seconds.
2. Remove the fuel filler cap.
3. Turn ON the ignition, with the engine OFF.
Is the fuel pump operating sound heard from the
fuel filler? —
Go to Step 4 Go to Step 7
4 Does the fuel pump operating sound stop after
approximately 12 seconds passed? —
Go to Step 21 Go to Step 5
5 1. Turn OFF the ignition for 30 seconds.
2. Replace the fuel pump relay with the head light relay or replace with a known good relay.
3. Turn ON the ignition, with the engine OFF.
Does the fuel pump operating sound stop after
approximately 12 seconds passed? —
Go to Step 20 Go to Step 6
6 Repair the short to battery or ignition voltage
between the fuel pump relay (pin 2 of X-13) and the
fuel pump (pin 1 of F-2).
Did you complete the repair? —
Go to Step 25
—
71. Turn OFF the ignition for 30 seconds.
2. Replace the fuel pump relay with the head light relay or replace with a known good relay.
3. Turn ON the ignition, with the engine OFF.
Is the fuel pump operating sound heard from the
fuel filler? —
Go to Step 17 Go to Step 8
8 Inspect the Fuel Pump (10A) fuse in the engine
room fuse block.
Is the Fuel Pump (10A) fuse open? —
Go to Step 9 Go to Step 10

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ISUZU KB P190 2007