Diagnostic Chart - Isuzu 4HL1 Workshop Manual

1A-88 Engine Control System

Diagnostic Chart

CAUTION:
The values in "Judgment criteria" may vary
depending on measurement conditions.
Chart 1 (1/3)
DTC Fault
14 CMP Sensor System Fault
15 CKP Sensor System Fault
18 Starter degradation
(VIM) (MT vehicles)
22 IAT Sensor System Fault
23 ECT Sensor System Fault
Accelerator Sensor
24
System Fault
25 Vehicle Speed Sensor
(VIM) System Fault
28 PTO Accelerator Sensor
(VIM) System Fault
31 Idle Up Volume System
(VIM) Fault
33 VIM Internal Fault
(VIM) (EEPROM Write Error)
ECM Internal Fault
34
(Charge Circuit Fault)
35 VIM Internal Fault
(VIM) (A/D Conversion Fault)
43 ITP Sensor System Fault
EGR Valve Position
44
Sensor System Fault
45 EGR Valve System Fault
Exhaust Brake System
Fault
(ON circuit open wiring)
46
(VIM)
Exhaust Brake System
Fault
(OFF circuit open wiring)
CHECK
ENGINE Judgment start conditions
lamp status
ON The battery voltage is at least 16 V
(idling only) and the starter switch is turned on.
ON The battery voltage is at least 16 V
(idling only) and the starter switch is turned on.
ON
(blinks 10
—
times and
turns off)
ON —
ON —
ON —
ON —
— —
— —
— —
The battery voltage is at least 16 V,
ON the starter switch is turned on, and
the post injection is not performed.
ON —
ON —
ON —
The starter switch is turned on for at
least 3 seconds, the EGR valve
position sensor is in normal
condition, neither #2 - 5 V Power
ON
Supply Fault nor A/D Conversion
Fault is detected, and the battery
voltage stays between 16 V and 32
V.
ON —
Judgment criteria
No CMP signal is input while the
CKP signal is input to the ECM 450
times.
No CKP signal is input while the
CMP signal is input to the ECM 40
times.
The manual transmission vehicle is
in idle stop and the accumulated
number of startups exceeds 150000.
The IAT sensor output voltage
deviates from the range between 0.1
V and 4.9 V for at least 2.9 seconds.
The ECT sensor output voltage
deviates from the range between 0.1
V and 4.9 V for at least 1 second.
The AP sensor output voltage
deviates from the range between 0.1
V and 4.8 V for at least 1 second.
The state where clutch and neutral
switches are in normal condition, the
automatic transmission or clutch
switch is turned off, the engine is
running at 2200 rpm or more, the
neutral switch is turned off, and the
vehicle speed is 0 km/h lasts 5
seconds.
The PTO accelerator sensor output
signal exceeds 4.9 V for 1 second.
The idle up volume output signal
deviates from the range between 0.2
V and 4.8 V for 1 second.
The stored count values do not
agree each other when the starter
switch position is changed from OFF
to ON.
The charge circuit voltage in the
ECM is excessively high or low.
The A/D (analog-to-digital)
conversion is not complete in the
VIM.
The ITP sensor output voltage
deviates from the range between 0.1
V and 4.9 V for at least 3 seconds.
The EGR valve position sensor
output voltage deviates from the
range between 0.3 V and 4.6 V for at
least 3 seconds.
The valve drive voltage is
excessively high for at least 10
seconds.
With the battery voltage at 20 V or
more, the engine speed at 500 rpm
or more, and the exhaust brake
turned on, the solenoid valve is
turned off for 1 second.
With the battery voltage at 20 V or
more, the engine speed at 500 rpm
or more, and the exhaust brake
turned off, the solenoid valve is
turned on for 1 second.
Fail-safe
When the CKP sensor is sound, the
ECM will control the powertrain
using the CKP signal.
When the CMP sensor is sound, the
ECM will control the powertrain
using the CMP signal.
—
The ECM controls the powertrain
using the set intake air temperature
(normal running phase: 25°C,
startup phase: –20°C).
The ECM controls the powertrain
using the set engine coolant
temperature (normal running phase:
55°C, startup phase: –20°C).
The ECM controls the accelerator
pedal position according to the
signals from the idle position switch.
—
The ECM controls the powertrain
using the set PTO accelerator
oposition (0 %).
The idle up volume switch is
disabled.
Counted and stored values are
reset.
All injectors are stopped.
Fault judgment is disabled on PTO
accelerator sensor, atmospheric
pressure sensor, and idle up
volume.
—
—
—
The exhaust brake system is
disabled.