Isuzu 4HL1, Workshop Manual

Page: 92 / 267

1A-90 Engine Control System
Chart 1 (3/3)
DTC Fault
CHECK
ENGINE
lamp status
Judgment start conditions Judgment criteria Fail-safe
217 SCV Drive System Short —
Pump control and pump feedback
are in normal mode, the SCV drive
efficiency ranges between 30 % and
50 %, and the battery voltage is at
least 16 V.
The SCV drive current is at least
1500 mA. (+B short is detected on
the circuit between SCV+ and
ECM.)
—
227
No Pump Pressure Feed
(Fuel Leak)
ON
The low-temperature startup mode
is currently not active (i.e., the
engine coolant temperature is 60°C
or more), high-pressure pump
control and injector control are in
normal mode, the engine is running
at or above 450 rpm, any of
Common Rail Pressure Sensor
System Fault (DTC115 or DTC245),
Injector Drive System Fault (DTC34,
DTC158, DTC159, DTC271,
DTC272, DTC273, or DTC274), or
Common Rail Pressure Fault
(DTC118) is not detected.
The fuel leak after the fuel filter
exceeds the threshold. The common rail pressure and fuel
injection quantity are limited.
241
Idle Position Switch Circuit
Open Wiring
ON —
The state where the AP sensor is in
normal condition, the AP sensor
output voltage is less than 0.6 V,
and the idle position switch is turned
off lasts at least 10 seconds.
The ECM controls the accelerator
position to 80 % or less.
242
Idle Position Switch Circuit
Short
ON —
The state where the AP sensor is in
normal condition, the AP sensor
output voltage is 1 V or more, and
the idle position switch is turned on
lasts at least 10 seconds.
—
245
Common Rail Pressure
Sensor System Fault
ON —
The state where the common rail
pressure sensor output voltage
deviates from the range between 0.7
V and 4.7 V is continuously
observed 3 times during A/D
conversion in the ECM.
The ECM controls the desired
common rail pressure to 60 MPa or
less and the desired fuel quantity to
50 mm
3
/st or less.
247 SCV Drive System Fault ON
Pump control and pump feedback
are in normal mode, the SCV drive
efficiency ranges between 30 % and
50 %, and the battery voltage is at
least 16 V.
The SCV drive current is 1100 mA
or less. (Short to ground between
SCV+ and ECM, +B short between
SCV– and ECM, short to ground
between SCV– and ECM, or open
wiring between SCV and ECM is not
detected.)
The common rail pressure and fuel
injection quantity are limited.
Fault judgment is disabled on pump
overpressure and short pump
pressure events 1 to 4.
271
Cylinder 1 (Injector Drive
System) Fault
ON
The battery voltage is at least 16 V,
the starter switch is turned on, and
the post injection is not performed.
Open wiring is detected on the
circuit between injector #1 and ECM
injector #1 pin, and Cylinder 4
(Injector Drive System) Fault
(DTC274) is not detected.
Injector #1 is stopped.
272
Cylinder 2 (Injector Drive
System) Fault
ON
The battery voltage is at least 16 V,
the starter switch is turned on, and
the post injection is not performed.
Open wiring is detected on the
circuit between injector #4 and ECM
injector #4 pin, and Cylinder 3
(Injector Drive System) Fault
(DTC273) is not detected.
Injector #4 is stopped.
273
Cylinder 3 (Injector Drive
System) Fault
ON
The battery voltage is at least 16 V,
the starter switch is turned on, and
the post injection is not performed.
Open wiring is detected on the
circuit between injector #2 and ECM
injector #2 pin, and Cylinder 2
(Injector Drive System) Fault
(DTC272) is not detected.
Injector #2 is stopped.
274
Cylinder 4 (Injector Drive
System) Fault
ON
The battery voltage is at least 16 V,
the starter switch is turned on, and
the post injection is not performed.
Open wiring is detected on the
circuit between injector #3 and ECM
injector #3 pin, and Cylinder 1
(Injector Drive System) Fault
(DTC271) is not detected.
Injector #3 is stopped.
277
Injector Power Supply
System Open Wiring
(Common 1)
ON
The battery voltage is at least 16 V,
the starter switch is turned on, and
the post injection is not performed.
Open wiring is detected between
injector #1/3 and ECM common 1
pin (both the drive circuits for
injectors #1 and #3 have open
wiring).
Injectors #1 and #3 are stopped.
278
Injector Power Supply
System Open Wiring
(Common 2)
ON
The battery voltage is at least 16 V,
the starter switch is turned on, and
the post injection is not performed.
Open wiring is detected between
injector #2/4 and ECM common 2
pin (both the drive circuits for
injectors #2 and #4 have open
wiring).
Injectors #2 and #4 are stopped.
416 Main Relay System Fault
ON
(idling only)
—
The state where the starter switch is
turned off and the main relay is
turned on lasts at least 5 seconds.
—
417
Starter Switch System
Fault
— —
The state where the starter switch is
in "ST" position and the engine
speed is more than 1000 rpm is
continuously observed 100 times.
—
543 High Engine Speed Error — —
The engine speed exceeds 4400
rpm. Injectors and supply pump are
stopped.