Daewoo CIELO EURO III Manual page 466

1F – 296 ENGINE CONTROLS
EXHAUST GAS RECIRCULATION (EGR) INSUFFICIENT FLOW
System Description
An Exhaust Gas Recirculation (EGR) system is used to
lower Oxides of Nitrogen (NOx) emission levels caused
by high combustion temperatures. It accomplishes this
by feeding small amounts of exhaust gases back into
the combustion chamber. When the air/fuel mixture is di-
luted with the exhaust gases, combustion temperatures
are reduced
A linear EGR valve is used on this system. The linear
EGR 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 through an
orifice with a engine
control module (ECM) controlled pintle. The ECM
controls the pintle position using inputs from the Throttle
Position (TP) and Manifold Absolute Pressure (MAP)
sensors. The ECM then commands the EGR
valve to operate when necessary by controlling an igni-
tion signal through the ECM. This can be moni-
tored on a scan tool as the Desired EGR Position.
The ECM monitors the results of its command
through a feedback signal. By sending a 5 volt reference
and a ground to the EGR valve, a voltage signal repre-
senting the EGR 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 EGR pintle.
The Actual EGR Position should always be near the
commanded or Desired EGR Position.
This diagnostic will determine if there is a reduction in
EGR flow.
Conditions for Setting the DTC
D DTC(s) P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0125, P0201, P0202, P0203,
P0204, P0351, P0352, P0402, P1404, P0405, P0406
and P0502 are not set.
D Test run in Decel Fuel Cut-Off (DFCO) mode.
D A/C clutch or transmission clutch are unchanged.
1.5L SOHC
D Barometric Pressure (BARO) is greater than 72 kPa.
D Vehicle speed is greater than 12.4 mph (20 km/h).
D Engine speed is between 1600 and 3200 rpm.
D Compensated MAP within range is between 10.3 and
50 kPa.
Start test:
D TPS is less than 1%.
D EGR is less than 1%.
D The change in the MAP is less than 1.2 kPa.
Test will be aborted when:
D The change in the vehicle speed is greater than 5
mph (8 km/h).
DIAGNOSTIC TROUBLE CODE (DTC) P0401
D The change in the rpm is greater than 50.
D EGR opened less than 90% commanded position.
Action Taken When the DTC Sets
D The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
D The ECM will store conditions which were pres-
ent when the DTC set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
D A history DTC is stored.
Conditions for Clearing the MIL/DTC
D A history DTC will clear after 40 consecutive warm up
cycles without a fault.
D DTC(s) can be cleared by using the scan tool.
DAEWOO T-154 BL2,3