Egr Control System Check - Isuzu N 2008 Series Workshop Manual

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 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.
Circuit/ System Testing EGR Control System Check
Step
Did you perform the Diagnostic System Check -
1 Engine Controls?
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
2
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"?
temperature, intake
Action
Engine Control System (4JJ1)
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
90 kPa (13 psi).
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
air
Value(s)
—
—
Yes
Go to Diagnostic
Go to Step 2
Refer to Applicable
DTC
1A-299
No
System Check -
Engine Controls
Go to Step 3