Isuzu KB P190. Manual - part 293

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 

 

Engine Control System (4JH1)  6E-139 

DTC P0380 (Symptom Code 8) (Flash Code 66) 

Circuit Description 
The engine control module (ECM) controls the glow
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 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 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 indicator

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 

 

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 

 

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 glow
indicator lamp and turns ON the glow plugs. After a
fixed time passes, the ECM turns OFF the glow
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 glow
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 longer
than 3 seconds when the lamp is commanded
OFF. 

 

Action Taken When the DTC Sets 

•  The ECM illuminates the malfunction indicator 

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 

