Isuzu N-Series. Service manual — part 661

6E-66 Engine Control System (4HK1)

Diagnostic Trouble Code (DTC) List

DTC

Flash
Code

MIL

Status

DTC Name

Condition for Running

the DTC

Condition for Setting the

DTC

Possible Cause

P0087

227

ON

Fuel Rail
Pressure (FRP)
Too Low

• DTCs P0090,

P0192, P0193,
P0201 – P0204,
P0611, P0612,
P1095, P1261,
P1262, P1630 and
P1635 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

Either of following
condition is met:

• The ECM detects

that the FRP sensor
signal voltage is 1.0
volt for 10 seconds
when the engine
speed is between 0
– 600 RPM.

• The ECM detects

that the FRP sensor
signal voltage is less
than 1.2 volts for 10
seconds when the
engine speed is
higher than 900
RPM.

• Fuel leaking at high

pressure side.

• Loss fuel or less fuel in

the fuel tank.

• Pressure limiter valve

opening pressure drop.

• Faulty fuel injector.
• Fuel suction side

looseness, kinks or
blocked.

• Faulty or clogged fuel

filter.

• FRP sensor circuit is

intermittently open
circuit, poor connection
or corrosion.

• FRP sensor circuit high

resistance.

• FRP regulator circuit is

intermittently open
circuit, poor connection
or corrosion.

• FRP regulator circuit

high resistance.

• Faulty FRP sensor.
• Faulty FRP regulator.
• Faulty fuel supply pump.

P0088

118

ON

Fuel Rail
Pressure (FRP)
Too High

• DTCs P0192,

P0193, P1630 and
P1635 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The engine is

running.

First Stage DTC

• The ECM detects

that the FRP sensor
signal voltage is
more than 3.9 volts
for longer than 10
second.

Second Stage DTC

• The ECM detects

that the FRP sensor
signal voltage is
more than 4.0 volts
for longer than 10
second during the
ignition cycle after
first stage has
occurred.

• Loss fuel or less fuel in

the fuel tank.

• Faulty fuel injector.
• Fuel suction side

looseness, kinks or
blocked.

• Faulty or clogged fuel

filter.

• FRP sensor circuit is

intermittently open
circuit, poor connection
or corrosion.

• FRP sensor circuit high

resistance.

• FRP regulator circuit is

intermittently open
circuit, poor connection
or corrosion.

• FRP regulator circuit

high resistance.

• Faulty FRP sensor.
• Faulty FRP regulator.
• Faulty fuel supply pump.

Engine Control System (4HK1) 6E-67

P0089

151

ON

Fuel Rail
Regulator
Performance

• DTCs P0090,

P0192, P0193,
P0201 – P0204,
P0611, P0612,
P1261, P1262,
P1630 and P1635
are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The engine is

running.

• The FRP regulator

command is more
than 40% or
commanded fuel
supply is less than a
predetermined
value.

Either of following
condition is met:

• The ECM detects

that the deferential
fuel rail pressure is
higher than 20 MPa
(2,900 psi) for longer
than 10 seconds
when the engine
speed is between 0
– 600 RPM.

• The ECM detects

that the differential
fuel rail pressure is
higher than 40 MPa
(5,800 psi) for longer
than 10 seconds
when the engine
speed is higher than
900 RPM.

• Faulty or clogged fuel

filter.

• FRP sensor circuit is

intermittently open
circuit, poor connection
or corrosion.

• FRP sensor circuit high

resistance.

• FRP regulator circuit is

intermittently open
circuit, poor connection
or corrosion.

• FRP regulator circuit

high resistance.

• Faulty FRP sensor.
• Faulty FRP regulator.
• Faulty fuel supply pump.

P0090

247

ON

Fuel Pressure
Regulator
Solenoid Control
Circuit

• DTC P1630 is not

set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The FRP regulator

command duty cycle
is between 10 –
90%.

Either of following
condition is met:

• The ECM detects

that the FRP
regulator solenoid
feedback current is
less than 50 mA.

• The ECM detects

that the FRP
regulator solenoid
feedback current is
more than 2400 mA.

• The ECM detects

that the difference of
commanded FRP
regulator solenoid
current and
feedback current is
more than 1000 mA.

• FRP regulator low

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

• FRP regulator high

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

• Poor harness connector

connection.

• Faulty FRP regulator.
• Faulty ECM.

P0107

71

ON

Barometric
Pressure Sensor
Circuit Low
Voltage

• DTCs P1630 and

P1632 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the BARO
sensor signal
voltage is less than
0.5 volts for 10
seconds.

• Sensor 5V reference

circuit is short to ground
or short to the low
reference circuit. (P1632
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.
• Faulty ECM.

DTC

Flash
Code

MIL

Status

DTC Name

Condition for Running

the DTC

Condition for Setting the

DTC

Possible Cause

6E-68 Engine Control System (4HK1)

P0108

71

ON

Barometric
Pressure Sensor
Circuit High
Voltage

• DTCs P1630 and

P1632 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the BARO
sensor signal
voltage is more than
4.9 volts for 10
seconds.

• Sensor 5V reference

circuit is short to battery
or ignition voltage.
(P1632 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.
• Faulty ECM.

P0112

22

ON

Intake Air
Temperature
(IAT) Sensor
Circuit Low
Voltage

• DTCs P1630 and

P1632 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the IAT sensor
signal voltage is less
than 0.1 volts for 10
seconds.

• Sensor signal circuit is

short to ground or short
to the low reference
circuit.

• Faulty sensor.
• Faulty ECM.

P0113

22

ON

Intake Air
Temperature
(IAT) Sensor
Circuit High
Voltage

• DTCs P1630 and

P1632 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The engine run time

is longer than 3
minutes.

• The ECM detects

that the IAT sensor
signal voltage is
more than 4.8 volts
for 10 seconds.

• Sensor signal circuit is

short to battery, ignition
voltage, short to any 5V
reference circuit, open
circuit, high resistance.

• Sensor low reference

circuit is open circuit or
high resistance.

• Poor harness connector

connection.

• Faulty sensor.
• Faulty ECM.

P0117

23

ON

Engine Coolant
Temperature
(ECT) Sensor
Circuit Low
Voltage

• DTCs P1630 and

P1634 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the ECT sensor
signal voltage is less
than 0.1 volts for 10
seconds.

• Sensor signal circuit is

short to ground or short
to the low reference
circuit.

• Faulty sensor.
• Faulty ECM.

P0118

23

ON

Engine Coolant
Temperature
(ECT) Sensor
Circuit High
Voltage

• DTCs P1630 and

P1634 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The engine run time

is longer than 3
minutes.

• The ECM detects

that the ECT sensor
signal voltage is
more than 4.8 volts
for 10 seconds.

• Sensor signal circuit is

short to battery, ignition
voltage, short to any 5V
reference circuit, open
circuit, high resistance.

• Sensor low reference

circuit is open circuit or
high resistance.

• Poor harness connector

connection.

• Faulty sensor.
• 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-69

P0182

221

ON

Fuel
Temperature
Sensor Circuit
Low Voltage

• DTCs P1630 and

P1634 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The ECM detects

that the FT sensor
signal voltage is less
than 0.1 volts for 10
seconds.

• Sensor signal circuit is

short to ground or short
to the low reference
circuit.

• Faulty sensor.
• Faulty ECM.

P0183

211

ON

Fuel
Temperature
Sensor Circuit
High Voltage

• DTCs P1630 and

P1634 are not set.

• The ignition switch is

ON.

• The ignition voltage

is more than 18
volts.

• The engine run time

is longer than 3
minutes.

• The ECM detects

that the FT sensor
signal voltage is
more than 4.8 volts
for 10 seconds.

• Sensor signal circuit is

short to battery, ignition
voltage, short to any 5V
reference circuit, open
circuit, high resistance.

• Sensor low reference

circuit is open circuit or
high resistance.

• Poor harness connector

connection.

• Faulty sensor.
• Faulty ECM.

P0192

245

ON

Fuel Rail
Pressure (FRP)
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 FRP sensor
signal voltage is less
than 0.7 volts.

• 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 or
high resistance.

• Sensor signal circuit is

short to ground or short
to the low reference
circuit.

• Poor harness connector

connection.

• Faulty sensor.
• Faulty ECM.

P0193

245

ON

Fuel Rail
Pressure (FRP)
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 FRP sensor
signal voltage is
more than 4.5 volts.

• Sensor 5V reference

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

• Sensor signal circuit is

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

• Sensor low reference

circuit is open circuit or
high resistance.

• Poor harness connector

connection.

• Faulty sensor.
• Faulty ECM.

DTC

Flash
Code

MIL

Status

DTC Name

Condition for Running

the DTC

Condition for Setting the

DTC

Possible Cause