Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 139

6E–160

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6

Using the DVM and check the glow relay power supply
circuit. 

1. Ignition “On”, engine “Off”. 

2. Remove the glow relay from the relay box. 

3. Check the circuit for open or short to ground

circuit. 

Was the DVM indicated specified value?

Battery 
voltage

Go to Step 8

Go to Step 7

7

Repair the open or short to ground circuit between the
ECM main relay and glow relay. 
Is the action complete?

—

Verify repair

—

8

Using the DVM and check the glow relay ground
circuit. 
Breaker box is available: 

1. Ignition “Off”, engine “Off”. 

2. Install the breaker box as type A. (ECM

disconnected) Ref. Page 6E-73 

3. Remove the glow relay from the relay box. 

4. Check the circuit for open or short to ground

circuit. 

Was the problem found?

Breaker box is not available: 

1. Ignition “Off”, engine “Off”. 

2. Disconnect the ECM connector. 

3. Remove the glow relay from the relay box. 

4. Check the circuit for open or short to ground

circuit. 

Was the problem found?

—

Repair faulty 
harness and 

verify repair

Go to Step 9

Step

Action

Value(s)

Yes

No

2

V

X-5

94

X-5

3

3

94

X-5

C-57

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–161

9

Is the ECM programmed with the latest software
release? 
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”. 
Was the problem solved?

—

Verify repair

Go to Step 10

10

Replace the ECM. 
Is the action complete? 
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.

—

Verify repair

—

Step

Action

Value(s)

Yes

No

6E–162

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

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

Glow Relay Circuit Voltage High

Step

Action

Value(s)

Yes

No

1

Was  the  “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to Step 2

Go to On Board 

Diagnostic 

(OBD) System 

Check

2

1. Connect the Tech 2. 

2. Review and record the failure information. 

3. Select “F0: Read DTC Infor As Stored By ECU” in

“F0: Diagnostic Trouble Codes”. 

Is the DTC P0380 (Symptom Code 8) stored as
“Present Failure”?

—

Go to Step 3

Refer to 

Diagnostic Aids 

and Go to Step 

3

3

1. Using the Tech 2, ignition “On” and engine “Off”. 

2. Select  “F1: Clear DTC Information” in “F0:

Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information. 

3. Operate the vehicle and monitor the “F0: Read

DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”. 

Was the DTC P0380 (Symptom Code 8) stored in this
ignition cycle?

—

Go to Step 4

Refer to 

Diagnostic Aids

4

Is the ECM programmed with the latest software
release? 
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”. 
Was the problem solved?

—

Verify repair

Go to Step 5

5

Substitute a known good ECM and recheck. 
Was the problem solved? 
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. 
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.  

—

Go to Step 6

—

6

Replace the ECM. 
Is the action complete? 
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. 
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.

—

Verify repair

—

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–163

DIAGNOSTIC TROUBLE CODE (DTC) P0381 (SUB CODE 4) (FLASH CODE 67) 

GLOW PLUG INDICATOR CIRCUIT VOLTAGE LOW

DIAGNOSTIC TROUBLE CODE (DTC) P0381 (SUB CODE 8) (FLASH CODE 67) 

GLOW PLUG INDICATOR CIRCUIT VOLTAGE HIGH

Condition for setting the DTC and action taken when the DTC sets

Circuit Description

The function of the glow time indicator lamp is to inform
the driver whether the glow system is activated.
When the lamp turned off, the engine can be started.
This does not imply that the glow plugs are no longer
activated.
In the after glow phase the lamp is not illuminated but

the glow plugs remain active for a certain period
depending on engine coolant temperature.

Diagnostic Aids

An intermittent may be caused by the following:

• Poor connections.

• Misrouted harness.

Flash 

Code

Code

Symptom 

Code

MIL

DTC Name

DTC Setting Condition

Fail-Safe (Back Up)

67

P0381

4

ON

Glow Plug Indicator Circuit 
Voltage Low

Glow plug indicator circuit 
open or short to ground cir-
cuit.

No fail-safe function.

8

ON

Glow Plug Indicator Circuit 
Voltage High

Glow plug indicator circuit 
short to voltage circuit.

Battery
Voltage

Ignition
SW

Meter
15A

A16

A7 A10

0.5
BLK/
YEL

Batt

Batt

0.5
RED/
WHT

29

0.5
ORG/
BLU

43

0.5
BRN/
YEL

42

0.5
BLK/
RED

27

0.5
BLU/
WHT

68

0.5
WHT

35

VSS

0.85
YEL

Imnobiliser

Control Unit

7

8

0.5
BRN/
YEL

IC

4P out

0.85
YEL

Glow

Check

Engine

Tacho

Meter

A/T

A1

TCM

µP

µP

µP

µP

Engine
Control
Module
(ECM)