Sensor Intermittent High Voltage - Daewoo CIELO EURO III Manual

1F – 107 ENGINE CONTROLS
INTAKE AIR TEMPERATURE (IAT) SENSOR INTERMITTENT HIGH VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The engine control module (ECM)
applies 5 volts through a pull-up resistor to the IAT
sensor. When the intake air is cold,
the resistance is high, and the ECM will monitor a
high signal voltage on the IAT signal circuit. If the intake
air is warm, the sensor resistance is lower causing the
ECM to monitor a lower voltage. DTC P1111 will
set when the ECM detects an excessively high
signal voltage on the intake air temperature sensor sig-
nal circuit.
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 not illumi-
nate.
DIAGNOSTIC TROUBLE CODE (DTC) P1111
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.
A history DTC is stored.
Conditions for Clearing the MIL/DTC
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
Check for the following conditions:
Poor connection at the ECM. Inspect harness
connectors for backed-out terminals, improper mat-
ing, broken locks, improperly formed or damaged ter-
minals, and poor terminal-to-wire connection.
Damaged harness. Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the IAT display on the scan tool while moving connec-
tors and wiring harnesses related to the IAT sensor. A
change in the IAT display will indicate the location of
the fault.
Reviewing the Fail Records vehicle mileage since the
diagnostic test last failed may help determine how
often the condition that caused the DTC to be set oc-
curs. This may assist in diagnosing the condition.
Use the Temperature vs. Resistance Values table to
evaluate the possibility of a skewed sensor. Refer to
"Temperature vs. Resistance" in this section.
TAAF150
DAEWOO T-154 BL2,3