Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual — part 43

4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

6E–167

DIAGNOSTIC TROUBLE CODE (DTC) P0380 (SYMPTOM CODE 4)

(FLASH CODE 66) GLOW RELAY CIRCUIT VOLTAGE LOW

DIAGNOSTIC TROUBLE CODE (DTC) P0380 (SYMPTOM CODE 8)

(FLASH CODE 66) GLOW RELAY CIRCUIT VOLTAGE HIGH

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

Circuit Description

The voltage on the coil of the relay glow plug is supplied
by the relay engine control module (ECM) main. The
ECM switches glow relay to operate glow plug depends
on the coolant temperature.

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.

Flash

Code

Code

Symptom

Code

MIL

DTC Name

DTC Setting Condition

Fail-Safe (Back Up)

66

P0380

4

ON

Glow Relay Circuit Voltage
Low

Glow relay circuit open or
short to ground circuit.

No fail-safe function.

8

ON

Glow Relay Circuit Voltage
High

Glow relay circuit short to volt-
age circuit.

Resister

A/C
Compressor

ECM
Main Relay

Battery
Voltage

Glow
80A

Glow
Relay

Glow
Plug

0.5
BLU/
RED

0.5
BLK/
BLU
94

0.5
BRN/
RED

0.5
BLK

41

0.5
GRN

33

5.0
RED/
WHT

0.5
BLU/
RED

0.5
GRY

0.5
GRN

0.5
GRN

0.5
BRN

0.5
GRY/
YEL

A/C
10A

Heater
Relay

Blower
20A

A/C
Compressor
Relay

A/C
Thermo
Relay

Pressure
SW

5.0
BLK/
RED

Electronic
Thermostat

µP

Batt

µP

Batt

IC

Engine
Control
Module
(ECM)

6E–168

4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Aids

An intermittent may be caused by the following:

• Poor connections.

• Misrouted harness.

• Rubbed through wire insulation.

• Broken wire inside the insulation.
Check for the following conditions:

• Poor connection at ECM-Inspect harness connectors

for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

• Damaged harness-Inspect the wiring harness for

damage. If the harness appears to be OK, observe
the DTC P0380 display on the Tech2 while moving
connectors and wiring harnesses. A change in the
display will indicate the location of the fault.

Diagnostic Trouble Code (DTC) P0380 (Symptom Code 4) (Flash Code 66)

Glow Relay Circuit Voltage Low

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 4) 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 4) stored in this
ignition cycle?

—

Go to Step 4

Refer to

Diagnostic Aids

and Go to Step

4

4

Check for poor/faulty connection at the glow relay or
ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?

—

Verify repair

Go to Step 5

94

3

4

2

1

C-49

4JA1-TC

X-12

4JH1-TC

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4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

6E–169

5

Using the DVM and check the glow relay.

1. Ignition “Off”, engine “Off”.

2. Remove the glow relay from the relay box.

3. Check the relay coil.

Was the DVM indicated specified value?

Continuity

Go to Step 6

Replace glow

relay and verify

repair

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

—

Step

Action

Value(s)

Yes

No

Glow Relay

2

3

2

V

C-49

4JA1-TC

X-12

4JH1-TC

2

1

C-49

X-4

4JA1-TC

X-12

4JH1-TC

6E–170

4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

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-81

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

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

94

3

C-49

4JA1-TC

X-12

4JH1-TC

3

94

C-57

C-49

4JA1-TC

X-12

4JH1-TC