Daewoo CIELO EURO III Manual page 313

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
stored in the Freeze Frame and Failure Records buff-
ers.
A history DTC is stored.
Both cooling fan turns ON.
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
When DTC P0125 is set, a skewed ECT sensor or a
stuck open thermostat is indicated.
An intermittent may be caused by a poor connection,
rubbed-through wire insulation or a wire broken inside
the insulation.
Check for a poor connection or damaged ECM
harness. Inspect the ECT sensor signal circuit and
ground circuit terminals for the following conditions:
Improper mating.
Broken locks.
Improperly formed.
Damaged terminals.
Poor terminal to wire connection.
DAEWOO T-154 BL2,3
ENGINE CONTROLS 1F – 144
Damaged harness.
Perform an intermittent test. If the connections and the
harness check OK, monitor a Digital Voltmeter (DVM)
connected between ECT sensor signal circuit and
ground circuit terminals while moving the related con-
nectors and the wiring harness. If a fault is induced, the
resistance reading will change. This may help to isolate
the location of the malfunction.
Use the Temperature vs. Resistance table to evaluate
the possibility of a skewed sensor.
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.
2. The engine must be allowed to cool fully before the
ECT and Idle Air Temperature (IAT) sensors will read
close to the ambient temperature in order to check
for a possible skewed sensor.
3. Measure the engine coolant temperature with a ther-
mometer to determine the actual value the ECT sen-
sor should be. Take into consideration if the engine
has been run and the engine coolant has been
warmed without opening the thermostat.
5. This step simulates a DTC P0117. If the ECM
senses the change, the ECM and wiring are
OK.
6. The ECT sensor, ECM and wiring have
checked OK at this point. Check for a proper thermo-
stat and cooling fan operation.
10. The replacement ECM must be programmed.
Refer to the latest Techline procedure for ECM
reprogramming.