Daewoo MATIZ Service Manual page 290

1F – 192 ENGINE CONTROLS
DIAGNOSTIC TROUBLE CODE (DTC) – P0404 ELECTRIC EXHAUST GAS
Circuit Description
An Electric Exhaust Gas Re-circulation (EEGR) system
is used to lower oxides of nitrogen (NOX) emission lev-
els caused by high combustion temperatures. It a ac-
complishes this by feeding small amounts of exhaust
gases back into the combustion chamber. When the air/
fuel mixture is diluted with the exhaust gases, combus-
tion temperatures are reduced.
A linear EEGR valve is used on this system. The linear
EEGR valve is designed to accurately supply exhaust
gases to the engine without the use of intake manifold
vacuum. The valve controls exhaust flow going into the
intake manifold from the exhaust manifold fhrough an
orifice with a engine control module(ECM) controlled
pintle. The ECM controls the pintle position using inputs
from the Throttle Position (TP) and the Manifold Abso-
lute Pressure (MAP) sensor. The ECM then commands
the EEGR valve to operate when necessary by control-
ling an ignition signal through the ECM. This can be
monitored on a scan tool as the Desired EEGR position.
The ECM monitors the results of its command through a
feedback signal. By sending a 5 volt reference and a
ground to the EEGR valve, a voltage signal representing
the EEGR valve pintle position is sent to the ECM. This
feedback signal can also be monitored on a scan tool
and is the actual position of the EEGR pintle. The actual
EEGR position should always be near the commanded
or Desired EEGR position.
ThisDiagnostic Trouble Code(DTC) will detect an open
or short circuit.
RECIRCULATION OPENED
Conditions for Setting THE DTC
D EEGR circuit low voltage.
Action Taken When the DTC Sets
D The Malfunction Indicator Lamp (MIL) will illuminate.
D The ECM will record operating conditions at the time
D A history DTC is stored.
D EEGR is disabled.
Conditions for Clearing the MIL/DTC
D The MIL will turn off after four consecutive ignition
D A history DTC will clear after 40 consecutive warm-up
D DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Due to moisture associated with exhaust systems, the
EEGR valve may freeze and stick in cold weather at
times. After the vehicle is brought into a warm shop for
repairs, the valve warms and the problem disappears.
By watching the Actual EEGR and desired EEGR posi-
tions on a cold vehicle with a scan tool, the fault can be
easily verified. Check the Freeze Frame data to deter-
mine if the DTC set when the vehicle was cold by view-
ing the Engine Coolant Temperature (ECT).
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.
cycles in which the diagnostic runs without a fault.
cycles without a fault.
MAA1F230
DAEWOO M-150 BL2