Isuzu N-Series. Manual — part 663

6E-74 Engine Control System (4HK1)

P0380

66

ON

Glow Plug Relay
Control Circuit

• The ignition switch is

ON.

• The battery voltage

is between 16 – 32
volts.

Either of following
condition is met:

• The ECM detects a

low voltage
condition on the
glow relay control
circuit when the
relay is commanded
OFF for longer than
5 seconds.

• The ECM detects a

high voltage
condition on the
glow relay control
circuit when the
relay is commanded
ON for longer than 5
seconds.

• Relay voltage feed circuit

is open circuit or high
resistance.

• Relay control circuit is

short to battery, ignition
voltage, short to ground,
open circuit or high
resistance.

• Poor harness connector

connection.

• Faulty relay.
• Faulty ECM.

P0381

67

OFF

Glow Plug Lamp
Control Circuit

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

Either of following
condition is met:

• The ECM detects a

low voltage
condition on the
glow indicator lamp
control circuit when
the indicator is
commanded OFF for
longer than 5
seconds.

• The ECM detects a

high voltage
condition on the
glow indicator lamp
control circuit when
the indicator is
commanded ON for
longer than 5
seconds.

• Lamp voltage feed circuit

is open circuit or high
resistance.

• Lamp control circuit is

short to battery, ignition
voltage, short to ground,
open circuit or high
resistance.

• Poor harness connector

connection.

• Faulty instrument panel

cluster.

• Faulty lamp.
• Faulty ECM.

P0485

44

ON

EGR Valve
Position Sensor
Circuit Low
Voltage

• DTCs P1630 and

P1635 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the EGR valve
position sensor
signal voltage is less
than 0.1 volts for 5
seconds.

• Sensor 5V reference

circuit is short to ground
or short to the low
reference circuit. (P1635
may also set.)

• Sensor 5V reference

circuit is open circuit,
high resistance.

• Sensor signal circuit is

open circuit, high
resistance, short to
ground or short to the
low reference circuit.

• Poor harness connector

connection.

• Faulty sensor. (EGR

valve)

• Faulty ECM.

DTC

Flash
Code

MIL

Status

DTC Name

Condition for Running

the DTC

Condition for Setting the

DTC

Possible Cause

Engine Control System (4HK1) 6E-75

P0486

44

ON

EGR Valve
Position Sensor
Circuit High
Voltage

• DTCs P1630 and

P1635 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the EGR valve
position sensor
signal voltage is
more than 4.9 volts
for 5 seconds.

• Sensor 5V reference

circuit is short to battery
or ignition voltage.
(P1635 may also set.)

• Sensor signal circuit is

short to battery, ignition
voltage or short to any
5V reference circuit.

• Sensor low reference

circuit is open circuit or
high resistance.

• Poor harness connector

connection.

• Faulty sensor. (EGR

valve)

• Faulty ECM.

P0488

45

ON

Exhaust Gas
Recirculation
(EGR) Valve
Performance

• DTCs P0485,

P0486, P1630 and
P1635 are not set.

• The ignition switch is

ON.

• The battery voltage

is between 20 – 32
volts.

• The ignition voltage

is more than 18
volts.

• The desired EGR

valve position is
stable.

• The ECM detects a

variance between
the actual EGR
valve position and
desired valve
position is more than
20% for longer than
20 seconds when
the EGR solenoid
command duty is
more than 90%.

• Valve stick.
• Motor voltage feed circuit

is short to battery,
ignition voltage, short to
ground, short to the
sensor low reference
circuit, open circuit or
high resistance.

• Duty signal circuit is

short to battery, ignition
voltage, short to ground,
short to the sensor low
reference circuit, open
circuit or high resistance.

• Poor harness connector

connection.

• Faulty EGR valve.
• Faulty ECM.

P0500

25

ON

Vehicle Speed
Sensor (VSS)
Circuit

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The engine speed is

more than 2000
RPM.

• The commanded

fuel is OFF
(accelerator pedal is
released).

• The ECM detects

that the VSS signals
are not generated
for 5 seconds.

• Faulty sensor

installation.

• Sensor voltage feed

circuit is open circuit or
high resistance.

• Sensor signal circuit is

short to battery, ignition
voltage, short to ground,
open circuit or high
resistance.

• Sensor low reference

circuit is open circuit or
high resistance.

• Poor harness connector

connection.

• Faulty sensor.
• Faulty ECM.
• Electromagnetic

interference and
electrical noise.

DTC

Flash
Code

MIL

Status

DTC Name

Condition for Running

the DTC

Condition for Setting the

DTC

Possible Cause

6E-76 Engine Control System (4HK1)

P0501

25

ON

Vehicle Speed
Sensor (VSS)
Performance

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the VSS signal
are changed larger
than a
predetermined
vehicle speed.

• Sensor installation is

poor condition.

• Sensor circuit is

intermittently open circuit
or poor connection.

• Faulty sensor.
• Electromagnetic

interference and
electrical noise.

P0601

53

ON

Control Module
Read Only
Memory (ROM)

—

• The ECM detects a

malfunction in its
internal flash read
memory (ROM).

• Faulty ECM.

P0603

54

ON

Control Module
Read Only
Memory (ROM)

—

Either of following
condition is met:

• The ECM detects a

malfunction in its
internal electrically
erasable &
programmable read
only memory
(EEPROM).

• The ECM detects

that the calculated
checksum does not
agree with the ECM
internal registered
checksum.

• Faulty ECM.

P0606 51/52

ON

Control Module
Internal
Performance

• The ignition switch is

ON.

• The battery voltage

is more than 16
volts.

Either of following
condition is met:

• The ECM detects a

malfunction in its
internal main central
processing unit
(CPU). (Flash Code
51)

• The ECM detects a

malfunction in its
internal sub CPU.
(Flash Code 52)

• ECM voltage feed circuit

is high resistance.

• ECM ground circuit is

open circuit or high
resistance.

• Faulty ECM.

P0611

34

ON

Fuel Injector
Control Module
Performance
Group 1

• The ignition switch is

ON.

• The battery voltage

is more than 18
volts.

• The ECM detects

that the common 1
fuel injector charge
up circuit is
insufficient charge.

• ECM voltage feed circuit

is high resistance.

• ECM ground circuit is

open circuit or high
resistance.

• Faulty ECM.

P0612

34

ON

Fuel Injector
Control Module
Performance
Group 2

• The ignition switch is

ON.

• The battery voltage

is more than 18
volts.

• The ECM detects

that the common 2
fuel injector charge
up circuit is
insufficient charge.

• ECM voltage feed circuit

is high resistance.

• ECM ground circuit is

open circuit or high
resistance.

• Faulty ECM.

DTC

Flash
Code

MIL

Status

DTC Name

Condition for Running

the DTC

Condition for Setting the

DTC

Possible Cause

Engine Control System (4HK1) 6E-77

P0615

19

ON

Starter Relay
Control Circuit

• The ignition switch is

ON.

• The battery voltage

is between 16 – 32
volts.

Either of following
condition is met:

• The ECM detects a

low voltage
condition on the
starter cut relay
control circuit when
the relay is
commanded OFF for
longer than 10
seconds.

• The ECM detects a

high voltage
condition on the
starter cut relay
control circuit when
the relay is
commanded ON for
longer than 10
seconds.

• Relay voltage feed circuit

is open circuit or high
resistance.

• Relay control circuit is

short to battery, ignition
voltage, short to ground,
open circuit or high
resistance.

• Poor harness connector

connection.

• Faulty relay.
• Faulty ECM.

P0650

77

OFF

Malfunction
Indicator Lamp
(MIL) Control
Circuit

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

Either of following
condition is met:

• The ECM detects a

low voltage
condition on the MIL
control circuit when
the indicator is
commanded OFF for
longer than 3
seconds.

• The ECM detects a

high voltage
condition on the MIL
control circuit when
the indicator is
commanded ON for
longer than 3
seconds.

• Lamp voltage feed circuit

is open circuit or high
resistance.

• Lamp control circuit is

short to battery, ignition
voltage, short to ground,
open circuit or high
resistance.

• Poor harness connector

connection.

• Faulty instrument panel

cluster.

• Faulty lamp.
• Faulty ECM.

DTC

Flash
Code

MIL

Status

DTC Name

Condition for Running

the DTC

Condition for Setting the

DTC

Possible Cause