Daewoo CIELO EURO III Manual page 260

1F – 9 1 ENGINE CONTROLS
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR RATIONALITY
Circuit Description
The engine control module (ECM) uses the
Manifold Absolute Pressure (MAP) sensor to control
the fuel delivery and the ignition timing.
The MAP sensor measures the changes in the
intake manifold pressure which results from engine load
(intake manifold vacuum) and the rpm changes due to
Throttle Position (TP) changes; and converts these
changes into voltage outputs. The ECM can detect
if the MAP sensor is not responding to the TP changes
by comparing the actual MAP change to a predicted
MAP change based on the amount of TP change that
occurs. If the ECM does not see the expected
MAP change or more, a Diagnostic Trouble Code (DTC)
P0106 will set.
Conditions for Setting the DTC
DTCs P0107, P0108, P0117, P0118, P0122, P0123,
P0201, P0202, P0203, P0204, P0300, P0351,
P0352, P0402, P0404, P0405, P0406, P0506,
P0507, P1404 not set.
Engine running.
Valid barometric pressure update.
A/C steady state.
The rpm is between 1300 and 4000.
No TP sensor fail conditions present.
No MAP fail conditions present.
The coolant temperature is greater than -10 C
(14 F).
1.5L SOHC
DTC P0125 is not set.
The change in rpm is less than 200.
The change in the TP sensor is less than 3%.
The change in Exhaust Gas Recirculation (EGR) is
less than 6%.
The change in Idle Air Control (IAC) is less than 5%.
All the above are stabilized for 1.5 seconds.
DIAGNOSTIC TROUBLE CODE (DTC) P0106
Action Taken When the DTC Sets
The Malfunction Indicator Lamp (MIL) will illuminate
after three (1.5L SOHC)consecutive trip with a fail.
The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records buff-
ers.
A history DTC is stored.
The ECM will substitute a fixed MAP value and
use TP to control the fuel delivery (the scan tool will
not show a defaulted value.)
Conditions for Clearing the MIL/DTC
The MIL will turn off after three (four –
1.5L SOHC) consecutive ignition cycles in which the
diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
With the ignition ON and the engine stopped, the man-
ifold pressure is equal to atmospheric pressure and the
signal voltage will be high. This information is used by
the ECM as an indication of vehicle altitude. Com-
parison of this reading with a known good vehicle with
the same sensor is a good way to check the accuracy of
a suspect sensor. Readings should be the same
r 0 .4 volt.
The MAP sensor vacuum source should be thoroughly
checked for restrictions at the intake manifold.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Table.
1. The On-Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the occurred. The information is then stored on the
scan tool for later reference.
2. A sensor that displays an ignition ON, engine OFF
BARO value that does not appear normal for the alti-
tude the vehicle is in should be considered to be mal-
functioning.
3. While starting the engine, the MAP sensor should
detect any changes in the manifold pressure. This
test is to determine if the sensor is stuck at a value.
4. A normal MAP sensor will react as quickly to the
throttle changes as the changes can be made. A
sensor should not appear to be lazy or catch up with
the throttle movements.
DAEWOO T-154 BL2,3