Multiple Pcm/Ecm Information Sensor Dtcs Set - Daewoo Nubira User Manual

MULTIPLE PCM/ECM INFORMATION SENSOR DTCS SET

Circuit Description
The powertrain control module (PCM)/engine control
module (ECM) monitors various sensors to determine en-
gine operating conditions. The PCM/ECM controls fuel de-
livery, spark advance, transaxle operation, and emission
control device operation based on the sensor inputs.
The PCM/ECM provides a sensor ground to all of the sen-
sors. The PCM/ECM applies 5 volts through a pullup resis-
tor 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 Tem-
perature (IAT) sensor, and the Transmission Fluid Tem-
perature (TFT) sensor. The PCM/ECM provides the Ex-
haust Gas Recirculation (EGR) Pintle Position Sensor, the
Throttle Position (TP) sensor, the Manifold Absolute Pres-
sure (MAP) sensor, the Air Conditioning Temperature
(ACT) sensor and the Fuel Tank Pressure Sensor with a
5 volt reference and a sensor ground signal. The PCM/
ECM monitors the separate feedback signals from these
sensors to determine their operating status.
Diagnostic Aids
Be sure to inspect PCM/ECM and engine grounds for be-
ing 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, P1625.
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 af-
fected circuit has been repaired. If the sensor has been
damaged, replace it.
An open in the sensor ground circuit between the PCM/
ECM and the splice will cause one or more of the following
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 PCM/ECM and
the splice will cause one or more of the following DTCs to
be set: P0107, P0112, P0117, P0122, P1107, P1112,
P1114, P1122.
DAEWOO V–121 BL4
ENGINE CONTROLS 1F – 33
Check for the following conditions:
S
Inspect for a poor connection at the PCM/ECM.
Inspect harness connectors for backed–out termi-
nals, improper mating, broken locks, improperly
formed or damaged terminals, and poor terminal–
to–wire connection.
S
Inspect the wiring harness for damage. If the har-
ness appears to be OK, observe an affected sen-
sor's displayed value on the scan tool with the igni-
tion ON and the engine OFF while moving
connectors and wiring harnesses related to the af-
fected 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 Diag-
nostic Table.
1. The Powertrain On–Board Diagnostic (OBD II) 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.
0. If a sensor input circuit has been shorted to voltage,
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
affected circuit has been repaired. A damaged ACT,
TP, MAP, Fuel Tank Pressure, or EGR Pintle Posi-
tion sensor will indicate a high or low voltage or
may be stuck at a fixed value after the affected cir-
cuit has been repaired. If the sensor has been dam-
aged, replace it.
21. The replacement PCM/ECM must be repro-
grammed. Refer to the latest Techline procedure for
PCM/ECM reprogramming.