2007 ISUZU KB P190 coolant

6E-120 Engine Control System (4JH1)
Step Action Value(s) Yes No
7 1. Turn OFF the ignition.
2. Disconnect the hand-held vacuum pump from the vacuum hose.
3. Connect the hand-held vacuum pump to the vacuum port of EGR valve.
4. Start the engine and let engine idle.
5. Apply vacuum pressure to the EGR valve while observing the MAF sensor parameter.
Does the MAF Sensor parameter decrease by at
least 200 mg/strk when the vacuum pressure is
applied? 

Go to Diagnostic Aids Go to Step 8
8 1. Turn OFF the ignition. 2. Disconnect the MAF sensor harness connector.
3. Inspect for an intermittent, for a poor connection and corrosion at the harness connector of the
MAF sensor (pin 3 of C-116 connector).
4. Disconnect the engine control module (ECM) harness connector.
5. Inspect for an intermittent, for a poor connection and corrosion on each MAF sensor circuit at the
harness connector of the ECM (pin 92 of C-57
connector).
6. Test for high resistance on each MAF sensor circuit.
7. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 11 Go to Step 9
9 Replace the EGR valve. Refer to EGR Valve Replacement in engine mechanical section.
Did you complete the replacement? 

Go to Step 11 
10 Replace the EGR solenoid valve. Refer to EGR
Solenoid Valve Replacement in this section.
Did you complete the replacement? 

Go to Step 11 
11 1. Reconnect all previously disconnected harness
connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine and warm up (allow engine coolant temperature to reach at least 60°C
[140°F]) while observing the MAF Sensor
parameter with the scan tool.
Does the MAF Sensor parameter follow the Desired
MAF parameter within 50 mg/strk? 

Go to Step 12 Go to Step 2
12 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK


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ISUZU KB P190 2007

6E-136 Engine Control System (4JH1)
DTC P0380 (Symptom Code 4) (Flash Code 66)
Circuit Description
The engine control module (ECM) controls the glo
w
relay which supplies power to the glow plugs based on
engine coolant temperature. In the after glow phase, the
glow indicator light is not illuminated but glow plugs
remain active for a certain period. If the ECM detects an
open circuit or short to ground on the glow relay control
circuit, this DTC will set.
Condition for Running the DTC
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the low voltage condition on
the glow relay control circuit for longer than 3
seconds when the relay is commanded OFF.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.

Condition for Clearing the MIL/DTC
• The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Notice:
• The glow relay is commanded OFF with ignition
ON and engine OFF when the engine coolant
temperature is reached at 30°C (86°F).
• The glow relay is commanded OFF with engine
run when the engine coolant temperature is
reached at 60°C (140°F).

DTC P0380 (Symptom Code 4) (Flash Code 66)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views


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 the scan tool. 2. Turn ON the ignition, with the engine OFF.
3. Perform the Glow Relay test with the scan tool.
4. Command the Glow Relay ON with the scan tool.
Does the glow relay click when commanded ON with
the scan tool? 

Go to Diagnostic Aids Go to Step 3
3 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. Command the Glow Relay ON with the scan tool.
Does the glow relay click when commanded ON with
the scan tool? 

Go to Step 12 Go to Step 4
4 1. Turn OFF the ignition. 2. Inspect the ECM (10A) fuse (EB-4) in the engine room fuse block.
Is the ECM (10A) fuse (EB-4) open? 

Go to Step 5 Go to Step 6
5 Replace the ECM (10A) fuse (EB-4). If the fuse continues to open, repair the short to ground on one
of the circuits that is fed by the ECM (10A) fuse (EB-
4) or replace the shorted attached component fed by
the ECM (10A) fuse (EB-4).
Did you complete the repair? 

Go to Step 16 
6 1. Turn OFF the ignition.
2. Remove the glow relay.
3. Connect a test lamp between the voltage feed circuit of the glow relay coil side (pin 2 of X-5
connector) and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate? 

Go to Step 7 Go to Step 9

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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-137
Step Action Value(s) Yes No
7 1. Turn OFF the ignition.
2. Connect a test lamp between the control circuit of the glow relay (pin 3 of X-5 connector) and
battery voltage.
3. Turn ON the ignition, with the engine OFF.
Does the test lamp continuously illuminate (the test
lamp blinks then goes out normally if the engine
coolant temperature lower than 30°C [86°F])? 

Go to Step 10 Go to Step 8
8 1. Keep the test lamp with connected. 2. Command the Glow Relay ON with the scan tool.
Does the test lamp illuminate when commanded ON
with the scan tool? 

Go to Step 12 Go to Step 11
9 Repair the voltage feed circuit between the ECM (10A) fuse (EB-4) and the glow relay (pin 2 of X-5
connector) for an open circuit or high resistance.
Did you complete the repair? 

Go to Step 16 
10 1. Test the control circuit of the glow relay between
the engine control module (ECM) (pin 94 of C-57
connector) and the glow relay (pin 3 of X-5
connector) for a short to ground.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 16 Go to Step 15
11 1. Test the control circuit of the glow relay between the ECM (pin 94 of C-57 connector) and the glow
relay (pin 3 of X-5 connector) for an open circuit
or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? 

Go to Step 16 Go to Step 13
12 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections on the glow relay terminals (pins 2
and 3 of X-5 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition? 

Go to Step 16 Go to Step 14
13 1. Turn OFF the ignition. 2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor connection on the glow relay control circuit at the
harness connector of the ECM (pin 94 of C-57
connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? 

Go to Step 16 Go to Step 15
14 Replace the glow relay. Did you complete the replacement? 

Go to Step 16 
15 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement? 

Go to Step 16 

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ISUZU KB P190 2007

6E-138 Engine Control System (4JH1)
Step Action Value(s) Yes No
16 1. Reconnect all previously disconnected fuse,
relay or harness connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine and warm up (allow engine coolant temperature to reach at least 65 °C
[149 °F]).
5. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 2 Go to Step 17
17 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK


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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-139
DTC P0380 (Symptom Code 8) (Flash Code 66)
Circuit Description
The engine control module (ECM) controls the glo
w
relay which supplies power to the glow plugs based on
engine coolant temperature. In the after glow phase, the
glow indicator light is not illuminated but glow plugs
remain active for a certain period. If the ECM detects a
short to battery or ignition voltage on the glow rela
y
control circuit, this DTC will set.
Condition for Running the DTC
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the high voltage condition
on the glow relay control circuit for longer than 1
second when the relay is commanded ON.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
Condition for Clearing the MIL/DTC
• The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Notice:
• The glow relay is commanded OFF with ignition
ON and engine OFF when the engine coolant
temperature is reached at 30°C (86°F).
• The glow relay is commanded OFF with engine
run when the engine coolant temperature is
reached at 60°C (140°F).

DTC P0380 (Symptom Code 8) (Flash Code 66)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views

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 the scan tool. 2. Turn ON the ignition, with the engine OFF.
3. Perform the Glow Relay test with the scan tool.
4. Command the Glow Relay ON with the scan tool.
Does the glow relay click when commanded ON with
the scan tool? 

Go to Diagnostic Aids Go to Step 3
3 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. Command the Glow Relay ON with the scan tool.
Does the glow relay click when commanded ON with
the scan tool? 

Go to Step 5 Go to Step 4
4 1. Test the control circuit of the glow relay between the engine control module (ECM) (pin 94 of C-57
connector) and the glow relay (pin 3 of X-5
connector) 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 7 Go to Step 6
5 Replace the glow relay. Did you complete the replacement? 

Go to Step 7 
6 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement? 

Go to Step 7 

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ISUZU KB P190 2007

6E-140 Engine Control System (4JH1)
Step Action Value(s) Yes No
7 1. Reconnect all previously disconnected relay or
harness connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Cool down the engine as necessary (allow engine coolant temperature to cool down at least
50 °C [122 °F]).
5. Start the engine.
6. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition? 

Go to Step 2 Go to Step 8
8 Observe the DTC Information with the scan tool. Are there any DTCs that you have not diagnosed?  Go to Diagnostic
Trouble Code (DTC) List System OK


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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-141
DTC P0381 (Symptom Code 4) (Flash Code 67)
Circuit Description
The glow indicator lamp is located on the instrument
panel cluster (IPC). The glow control system is operated
when the engine coolant temperature is low, which
allows easier engine starting. If the ignition switch is
turned ON when the engine coolant temperature is low,
the engine control module (ECM) illuminates the glo
w
indicator lamp and turns ON the glow plugs. After a
fixed time passes, the ECM turns OFF the glo
w
indicator lamp and the glow plugs. The ECM monitors
the glow indicator lamp control circuit for conditions that
are incorrect for the commanded state of the glo
w
indicator lamp. If the ECM detects an open circuit or
short to ground on the glow indicator control circuit, this
DTC will set.
Condition for Running the DTC
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects that the low voltage condition on
the glow indicator lamp control circuit for longe
r
than 3 seconds when the lamp is commanded
OFF.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
Condition for Clearing the MIL/DTC
• The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
Notice:
• The glow indicator lamp is commanded OFF with
the ignition ON and engine OFF when the engine
coolant temperature is reached at 30°C (86°F).

DTC P0381 (Symptom Code 4) (Flash Code 67)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views

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 the scan tool. 2. Turn ON the ignition, with the engine OFF.
3. Perform the Glow Indicator test with the scan tool.
4. Command the Glow Indicator ON with the scan tool.
Does the glow indicator lamp turn ON when
commanded ON with the scan tool? 

Go to Step 3 Go to Step 4
3 Command the Glow Indicator OFF with the scan tool.
Does the glow indicator lamp OFF? 

Go to Step 17 Go to Step 10
4 1. Turn OFF the ignition. 2. Inspect the Meter (15A) fuse (C-14) in the cabin fuse block.
Is the Meter (15A) fuse (C-14) open? 

Go to Step 5 Go to Step 6
5 Replace the Meter (15A) fuse (C-14). If the fuse continues to open, repair the short to ground on one
of the circuits that fed by the Meter (15A) fuse (C-14)
or replace the shorted attached component fed by
the Meter (15A) fuse (C-14).
Did you complete the repair? 

Go to Step 19 

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ISUZU KB P190 2007

6E-144 Engine Control System (4JH1)
DTC P0381 (Symptom Code 8) (Flash Code 67)
Circuit Description
The glow indicator lamp is located on the instrument
panel cluster (IPC). The glow control system is operated
when the engine coolant temperature is low, which
allows easier engine starting. If the ignition switch is
turned ON when the engine coolant temperature is low,
the engine control module (ECM) illuminates the glo
w
indicator lamp and turns ON the glow plugs. After a
fixed time passes, the ECM turns OFF the glo
w
indicator lamp and the glow plugs. The ECM monitors
the glow indicator lamp control circuit for conditions that
are incorrect for the commanded state of the glo
w
indicator lamp. If the ECM detects a short to battery or
ignition voltage on the glow indicator control circuit, this
DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the high voltage condition
on the glow indicator lamp control circuit for longe
r
than 1 second when the lamp is commanded ON.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
Condition for Clearing the MIL/DTC
• The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
Notice:
• The glow indicator lamp is commanded OFF with
the ignition ON and engine OFF when the engine
coolant temperature is reached at 30°C (86°F).
Test Description
The number below refers to the step number on the
diagnostic table.
3. If the control circuit of the glow indicator lamp
between the ECM and the IPC is normal, the control
circuit voltage low DTC P0381 (Symptom Code 4) will
set.

DTC P0381 (Symptom Code 8) (Flash Code 67)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views

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 the scan tool. 2. Turn ON the ignition, with the engine OFF.
3. Perform the Glow Indicator test with the scan tool.
4. Command the Glow Indicator ON with the scan tool.
Does the glow indicator lamp turn ON when
commanded ON with the scan tool? 

Go to Diagnostic Aids Go to Step 3
3 1. Turn OFF the ignition. 2. Remove the instrument panel cluster (IPC) in order to disconnect the IPC harness B-24
connector.
3. Disconnect the IPC harness B-24 connector.
4. Turn ON the ignition for 30 seconds, with the engine OFF.
5. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.
Does DTC P0381 (Symptom Code 4) set, but not
DTC P0381 (Symptom Code 8)? 

Go to Step 5 Go to Step 4

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ISUZU KB P190 2007