Isuzu 2008MY N Series, Руководство по ремонту

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Engine Control System (4HK1) 1A-319
EGR Control System Check
Description
The EGR system recirculates a part of exhaust gas
back into the intake manifold, which results in reducing
NOx emissions. The EGR control system uses an
electronic control system to ensure both driveability
and low emission. A control current from the ECM
operates a solenoid to control the lift amount of EGR
valve. Also, an EGR position sensor is provided at the
rear of the solenoid to feed actual valve lift amount
back to the ECM for more precision control.
The EGR control starts when the conditions for engine
speed, engine coolant temperature, intake air
temperature and barometric pressure are satisfied.
Then, the valve opening is calculated according to the
engine speed, and target fuel injection quantity. Based
on this valve opening, the drive duty of the solenoid is
determined and the valve is driven accordingly. The
intake throttle valve is provided to adequate intake
manifold depression to ensure EGR gas flow.
EGR Control Operation
• The engine coolant temperature (ECT) is between
70
°
C (158
°
F) and 100
°
C (212
°
F).
• The intake air temperature (IAT) is more than -
30
°
C (-22
°
F).
• The barometric pressure (BARO) is more than
90kPa (13psi).
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing EGR Control System Check
Step Action Value(s) Yes No
1
Did you perform the Diagnostic System Check
- Engine Controls?
—
Go to Step 2
Go to Diagnostic
System Check -
Engine Controls
2
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with a scan tool.
Are any DTCs set in which the "Action Taken
When the DTC Sets" under that particular
code states, "The ECM inhibits EGR control"?
—
Go to Applicable
DTC Go to Step 3
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