Daewoo CIELO EURO III Manual page 290

1F – 1 2 1 ENGINE CONTROLS
ENGINE COOLANT TEMPERATURE (ECT) SENSOR INTERMITTENT HIGH
Circuit Description
The Engine Coolant Temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
engine control module (ECM) applies a voltage
(about 5.0 volts) through a pull–
up resistor to the ECT signal circuit. When the engine
coolant is cold, the sensor resistance is high, and the
ECM will monitor a high signal voltage. As the en-
gine coolant warms, the sensor resistance is less, and
the ECT signal voltage measured at the ECM
drops. With a fully warmed up engine, the ECT signal
voltage should measure about 1.5 to 2.0 volts. If the
ECM detects an ECT signal that is intermittently
above the range of the ECT sensor, a DTC P1115 will
set.
Conditions for Setting the DTC
Engine run time is greater than 90 seconds.
Action Taken When the DTC Sets
The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
The ECM will store conditions which were pres-
ent when the DTC was set as Failure Records data
only. This information will not be stored as Freeze
Frame data.
A history DTC is stored.
DIAGNOSTIC TROUBLE CODE (DTC) P1115
VOLTAGE
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 ECT display on the scan tool while moving con-
nectors and wiring harnesses related to the ECT sen-
sor. A change in the ECT 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.
TAA1F160
DAEWOO T-154 BL2,3