Daewoo CIELO EURO III, Manual

Page: 200 / 603

1F –32 ENGINE CONTROLS
DAEWOO T-154 BL2,3
MULTIPLE ECM INFORMATION SENSOR DTCS SET
System Description
Th e engine control
module (ECM) monitors various sensors to determine
engine operating conditions. The ECM controls
fuel delivery, spark advance, transaxle operation, and
emission control device operation based on the sensor
inputs.
The ECM provides a sensor ground to all of the
sensors. The ECM applies 5 volts through a pull–
up resistor and monitors the voltage present between
the sensor and the resistor to determine the status of the
Engine Coolant Temperature (ECT) sensor, the Intake
Air Temperature (IAT) sensor, and the Transmission
Fluid Temperature (TFT) sensor. The ECM pro-
vides the Exhaust Gas Recirculation (EGR) Pintle Posi-
tion sensor, the Throttle Position (TP) sensor, the
Manifold Absolute Pressure (MAP) sensor, and the Fuel
Tank Pressure sensor with a 5 volt reference and a sen-
sor ground signal. The ECM monitors the separate
feedback signals from these sensors to determine their
operating status.
Diagnostic Aids
Be sure to inspect the ECM and engine grounds
for being secure and clean.
A short to voltage in one of the sensor circuits can cause
one or more of the following diagnostic trouble codes
(DTCs) to be set: P0108, P0113, P0118, P0123, P1106,
P1111, P1115, P1121.
If a sensor input circuit has been shorted to voltage, en-
sure that the sensor is not damaged. A damaged sensor
will continue to indicate a high or low voltage after the
affected circuit has been repaired. If the sensor has
been damaged, replace it.
An open in the sensor ground circuit between the
ECM and the splice will cause one or more of the follow-
ing DTCs to be set: P0108, P0113, P0118, P0123,
P1106, P1111, P1115, P1121.
A short to ground in the 5 volt reference circuit or an
open in the 5 volt reference circuit between the
ECM and the splice will cause one or more of the follow-
ing DTCs to be set: P0107, P0112, P0117, P0122,
P1107, P1112, P1114, P1122.
Check for the following conditions:
Inspect for a poor connection at the ECM. In-
spect harness connectors for backed out terminals,
improper mating, broken locks, improperly formed or
damaged terminals, and poor terminal to wire con-
nection.
Inspect the wiring harness for damage. If the harness
appears to be OK, observe an affected sensor’s dis-
played value on the scan tool with the ignition ON and
the engine OFF while moving connectors and wiring
harnesses related to the affected sensors. A change
in the affected sensor’s displayed value will indicate
the location of the fault.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Table.
1. The powertrain On-Board Diagnostic (EOBD) sys-
tem check prompts the technician to complete some
basic checks and store the freeze frame and failure
records 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.
9. A faulty EGR valve can leak a small amount of cur-
rent from the ignition feed circuit to the 5 volt refer-
ence circuit. If the problem does not exist with the
EGR valve disconnected, replace the EGR valve.
11 – 19. If a sensor input circuit has been shorted to volt-
age, ensure that the sensor has not been damaged.
A damaged IAT or ECT sensor will continue to indi-
cate a high voltage or low temperature after the af-
fected circuit has been repaired. A damaged TP,
MAP, fuel tank pressure, or EGR Pintle Position
sensor will indicate a high or low voltage or may be
stuck at a fixed value after the affected circuit has
been repaired. If the sensor has been damaged, re-
place it.
20. ECM must be programmed. Refer to the latest
Techline procedure for ECM reprogramming.