Daewoo CIELO EURO III Manual page 284

1F – 115 ENGINE CONTROLS
INTAKE AIR TEMPERATURE (IAT) SENSOR HIGH VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor uses a thermis-
tor to control the signal voltage to the
engine control module (ECM). The
ECM supplies a 5 volt reference and a ground to the
sensor. When the air is cold, the resistance is high;
therefore the IAT signal voltage will be high. If the intake
air is warm, resistance is low; therefore the IAT signal
voltage will be low.
Conditions for Setting the DTC
DTC P0502 is not set.
Engine run time is greater than 120 Seconds.
1.5L SOHC
IAT is less than –38 C (–36.4 F).
Vehicle speed is less than 18.6 mph (25 km/h).
Engine coolant temperature is greater than 70 C
(158 F).
Airflow is less than 15 g/s.
Action Taken When the DTC Sets
The Malfunction Indicator Lamp (MIL) will illuminate
after three (1.5L SOHC) or
consecutive trip with a fail.
The ECM will record operating conditions at the
time the diagnostic fails. This information will be
DIAGNOSTIC TROUBLE CODE (DTC) P0113
stored in the Freeze Frame and Failure Records buff-
ers.
A history DTC is stored.
The ECM will substitute a default value for IAT.
The scan tool will not show the 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.
The DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
If the vehicle is at ambient temperature, compare the
IAT sensor to the Engine Coolant Temperature (ECT)
sensor. The IAT sensor and the ECT sensor should be
relatively close to each other.
Use the Temperature vs. Resistance Values table to
evaluate the possibility of a skewed sensor. Refer to
"Temperature vs. Resistance" in this section.
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 malfunction occurred. The information is then
stored on the scan tool for later reference.
TAAF150
DAEWOO T-154 BL2,3