display DAEWOO NUBIRA 2004 Service Repair Manual

SECTION : 1F
ENGINE CONTROLS
CAUTION : Disconnect the negative battery cable before removing or installing any electrical unit o r w hen a
tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable will
help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise
noted.
TABLE OF CONTENTS
SPECIFICATIONS1F–6 . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Data Display Tables 1F–6. . . . . . . . . . . . . . . . .
Engine Data Display Table Definitions 1F–7. . . . . . . .
Fastener Tightening Specifications 1F–10. . . . . . . . .
Fuel System Specifications 1F–11. . . . . . . . . . . . . . . . .
Temperature Vs Resistance 1F–11. . . . . . . . . . . . . . . .
SCHEMATIC AND ROUTING DIAGRAMS1F–12 . . . .
ECM Wiring Diagram
(1.4L/1.6L DOHC – 1 OF 6) 1F–12. . . . . . . . . . . . . .
ECM Wiring Diagram
(1.4L/1.6L DOHC – 2 OF 6) 1F–13. . . . . . . . . . . . . .
ECM Wiring Diagram
(1.4L/1.6L DOHC – 3 OF 6) 1F–14. . . . . . . . . . . . . .
ECM Wiring Diagram
(1.4L/1.6L DOHC – 4 OF 6) 1F–15. . . . . . . . . . . . . .
ECM Wiring Diagram
(1.4L/1.6L DOHC – 5 OF 6) 1F–16. . . . . . . . . . . . . .
ECM Wiring Diagram
(1.4L/1.6L DOHC – 6 OF 6) 1F–17. . . . . . . . . . . . . .
ECM Wiring Diagram (1.8L DOHC – 1 OF 6) 1F–18.
ECM Wiring Diagram (1.8L DOHC – 2 OF 6) 1F–19.
ECM Wiring Diagram (1.8L DOHC – 3 OF 6) 1F–20.
ECM Wiring Diagram (1.8L DOHC – 4 OF 6) 1F–21.
ECM Wiring Diagram (1.8L DOHC – 5 OF 6) 1F–22.
ECM Wiring Diagram (1.8L DOHC – 6 OF 6) 1F–23.
Connector End View 1F–24. . . . . . . . . . . . . . . . . . . . . .
COMPONENT LOCATOR1F–28 . . . . . . . . . . . . . . . . . . .
Component Locator (1.4L/1.6L DOHC) 1F–28. . . . . .
Component Locator (1.8L DOHC) 1F–29. . . . . . . . . . .
DIAGNOSIS1F–30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SYSTEM DIAGNOSIS 1F–30. . . . . . . . . . . . . . . . . . . . . .
Diagnostic Aids 1F–30. . . . . . . . . . . . . . . . . . . . . . . . . . .
Idle Learn Procedure 1F–30. . . . . . . . . . . . . . . . . . . . . .
TEC (Tooth Error Correction) Learn Procedure 1F–31ON–Board Diagnostic (EOBD) System Check
(1.4L/1.6L DOHC) 1F–32. . . . . . . . . . . . . . . . . . . . . . .
ON–Board Diagnostic (EOBD) System Check
(1.8L DOHC) 1F–34. . . . . . . . . . . . . . . . . . . . . . . . . . .
Multiple ECM Informationn Sensor Dtcs Set 1F–36. .
Engine Cranks But Will Not Run
(1.4L/1.6L DOHC) 1F–40. . . . . . . . . . . . . . . . . . . . . . .
Engine Cranks But Will Not Run (1.8L DOHC) 1F–47
No Malfunction Indicator Lamp (
1.4L/1.6L DOHC) 1F–54. . . . . . . . . . . . . . . . . . . . . . .
No Malfunction Indicator Lamp (1.8L DOHC) 1F–56.
Malfunction Indicator Lamp On Steady (1.4L/1.6L
DOHC) 1F–58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Malfunction Indicator Lamp On Steady
(1.8L DOHC) 1F–60. . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel System Diagnosis 1F–62. . . . . . . . . . . . . . . . . . . .
Fuel Pump Relay Circuit Check
(1.4L/1.6L DOHC) 1F–65. . . . . . . . . . . . . . . . . . . . . . .
Fuel Pump Relay Circuit Check (1.8L DOHC) 1F–68.
Main Relay Circuit Check (1.4L/1.6L DOHC) 1F–71.
Main Relay Circuit Check (1.8L DOHC) 1F–73. . . . . .
Manifold Absolute Pressure Check
(1.4L/1.6L DOHC) 1F–75. . . . . . . . . . . . . . . . . . . . . . .
Manifold Absolute Pressure Check
(1.8L DOHC) 1F–77. . . . . . . . . . . . . . . . . . . . . . . . . . .
Idle Air Control System Check
(1.4L/1.6L DOHC) 1F–79. . . . . . . . . . . . . . . . . . . . . . .
Idle Air Control System Check (1.8L DOHC) 1F–82. .
Ignition System Check (1.4L/1.6L DOHC) 1F–85. . . .
Ignition System Check (1.8L DOHC) 1F–88. . . . . . . .
Engine Cooling Fan Circuit Check – Dual Fan
(1.4L/1.6L DOHC) 1F–93. . . . . . . . . . . . . . . . . . . . . . .
Engine Cooling Fan Circuit Check – Dual Fan
(1.8L DOHC) 1F–100. . . . . . . . . . . . . . . . . . . . . . . . . .
Data Link Connector Diagnosis
(1.4L/1.6L DOHC) 1F–106. . . . . . . . . . . . . . . . . . . . . .
Data Link Connector Diagnosis (1.8L DOHC) 1F–108
Fuel Injector Balance Test 1F–110. . . . . . . . . . . . . . . .

1F – 6IENGINE CONTROLS
DAEWOO V–121 BL4
SPECIFICATIONS
ENGINE DATA DISPLAY TABLES
Engine Data Display
Parameter
ScalingValue
Desired Idle SpeedRPMECM idle command (varies with temperature)
Engine RPMRPM± 50 RPM from desired RPM in drive (A/T) ± 50 RPM
from desired RPM in neutral (M/T)
MAPkPa29 – 55 (varies with manifold and barometric pressure)
Throttle Position VoltV0 v
Start–up IAT°Cvaries
Intake Air Temperature°C10 – 90 °C
Coolant Temperature (Start–up)°Cvaries
Engine Coolant Temperature°C85 – 105 °C
IAC Motor Position–1 – 50
O2 Sensor (B1–S1)mV1–1000 mV (varies continuously)
O2 Sensor (B1–S2)mV1–1000 mV (varies continuously)
Fuel System StatusClosed Loop/Open
Loop”Closed Loop” (may enter ”Open Loop” at extended idle)
Rich/Lean (B1–S1)Rich/Leanvaries
Lean to Rich AveragemS10 –211 ms or 0 ms
Rich to Lean AveragemS10 –211 ms or 0 ms
Engine Load Value%0 – 100 % (varies)
Short Term Fuel Trim%–30 – 30%
Long Term Fuel Trim%–30 – 30%
Linear EGR FeedbackVvaries
EGR Duty Cycle%0 %
EGR EWMA Result–< = 0
Spark Advance°varies
MIL OdometerKm0 Km
MIL On TimeMin0 Min
Base Injection PWMmS1.0 – 5.0 ms
Barometric PressurekPavaries with altitude
Ignition VoltageV13.5 – 14.8 V
Air/Fuel RatioRatio14.6 (Closed Loop Enable)
Calculated Air FlowG/Svaries
Total Misfire (Current)–0
Misfire History Cyl. 1–0
Misfire History Cyl. 2–0
Misfire History Cyl. 3–0
Misfire History Cyl. 4–0
Vehicle SpeedKm/H0 Km/H
A/C PressureVvaries

ENGINE CONTROLS 1F – 7
DAEWOO V–121 BL4
Parameter ValueScaling
A/C RequestYes/NoNo
A/C ClutchOn/OffOff
Fuel Pump CommandOn/OffOn
Closed LoopYes/NoYe s
Throttle At IdleYes/NoNo
O2 Ready (B1–S1)Yes/NoYe s
Knock PresentYes/NoNo
Fan LowOn/OffOn/Off
Fan HighOn/OffOn/Off
TCC Engaged (Only AT)Yes/NoYe s
Park/Neutral (Only AT)P/N and R/N/DP/N
Fuel Level InputVvaries
Fuel Level Output%varies
Fuel Trim Cell–18
G–SensorV1.1 – 3.7 V (Non–ABS Only)
Engine RuntimeHH:MM:SSHours:Minutes:Seconds
* Condition: Warmed up, idle, park or neutral, A/C off
ENGINE DATA DISPLAY TABLE
DEFINITIONS
ECM Data Description
The following information will assist in diagnosing emis-
sion or driveability problems. A first technician can view
the displays while the vehicle is being driven by second
technician. Refer to Powertrain On–Board Diagnostic
(EOBD) System Check for addition information.
A/C Clutch
The A/C Relay represents the commanded state of the
A/C clutch control relay. The A/C clutch should be en-
gaged when the scan tool displays ON.
A/C Pressure
The A/C High Side displays the pressure value of the A/C
refrigerant pressure sensor. The A/C High Side helps to
diagnose the diagnostic trouble code (DTC) P0533.
A/C Request
The A/C Request represents whether the air conditioning
is being requested from the HVAC selector. The input is re-
ceived by the instrument panel cluster and then sent serial
data to the ECM and finally to the scan tool over KWP 2000
serial data.
Air Fuel Ratio
The Air Fuel Ration indicates the air to fuel ratio based on
the Front Heated Oxygen Sensor (HO2S1) inputs. The
ECM uses the fuel trims to adjust fueling in order to at-
tempt to maintain an air fuel ratio of 14.7:1.BARO
The Barometric Pressure (BARO) sensor measures the
change in the intake manifold pressure which results from
altitude changes. This value is updated at ignition ON and
also at Wide Open Throttle (WOT).
Base Injection PWM
Indicates the base Pulse Width Modulation (PWM) or ON
time of the indicated cylinder injector in milliseconds.
When the engine load is increased, the injector pulse width
will increase.
Calculated Air Flow
The calculated air flow is a calculation based on manifold
absolute pressure. The calculation is used in several diag-
nostics to determine when to run the diagnostics.
Desired Idle Speed
The ECM commands the idle speed. The ECM compen-
sates for various engine loads in order to maintain the de-
sired idle speed. The actual engine speed should remain
close to the desired idle under the various engine loads
with the engine idling.
Engine Coolant Temperature
The Engine Coolant Temperature (ECT) sensor sends en-
gine temperature information to the ECM. The ECM sup-
plies 5 volts to the engine coolant temperature sensor cir-
cuit. The sensor is a thermistor which changes internal
resistance as temperature changes. When the sensor is
cold (internal resistance high), the ECM monitors a high
voltage which it interprets as a cold engine. As the sensor
warms (internal resistance decreases), the voltage signal
will decrease and the ECM will interpret the lower voltage
as a warm engine.

1F – 8IENGINE CONTROLS
DAEWOO V–121 BL4
EGR Desired Position
The desired exhaust gas recirculation (EGR) position is
the commanded EGR position. The ECM calculates the
desired EGR position. The higher the percentage, the lon-
ger the ECM is commanding the EGR valve ON.
Engine Load
Indicates engine load based on manifold absolute pres-
sure. The higher the percentage, the more load the engine
is under.
Engine Run Time
The engine run time is a measure of how long the engine
has been running. When the engine stops running, the tim-
er resets to zero.
Engine Speed
Engine Speed is computed by the ECM from the fuel con-
trol reference input. It should remain close to desired idle
under the various engine loads with the engine idling.
Fan
The Fan Control (FC) Relay is commanded by the ECM.
The FC Relay displays the command as ON or OFF.
Fuel Level Sensor
The Fuel Level Sensor monitors the fuel level in the tank.
The Fuel Level Sensor monitors the rate of change of the
air pressure in the EVAP system. Several of the Enhanced
EVAP System diagnostics are dependent upon the correct
fuel level.
Fuel System Status
The Closed Loop is displayed indicating that the ECM is
controlling the fuel delivery according to the Front Heated
Oxygen Sensor (HO2S1) voltage as close to an air/fuel ra-
tio of 14.7 to 1 as possible.
IAC Position
The scan tool displays the ECM command for the Idle Air
Control (IAC) pintle position in counts. The higher the
number of counts, the greater the commanded idle speed
reads. The Idle Air Control responds to changes in the en-
gine load in order to maintain the desired idle rpm.
Ignition 1 (Voltage)
The ignition volts represent the system voltage measured
by the ECM at the ignition feed circuit.
Intake Air Temperature
The ECM converts the resistance of the Intake Air Tem-
perature (IAT) sensor to degrees in the same manner as
the engine coolant temperature (ECT) sensor. In take air
temperature is used by the ECM to adjust fuel delivery and
spark timing according to incoming air density.Knock Present
The KS Noise Channel indicates when the ECM detects
the KS signal. The ECM should display NO at idle.
Long Term FT
The Long Term Fuel Trim (FT) is derived from the short
term fuel trim value. The Long Term FT is used for the long
term correction of the fuel delivery. A value of 128 counts
(0%) indicates that the fuel delivery requires no com-
pensation in order to maintain a 14.7:1 air to fuel ratio. A
value below 128 counts means that the fuel system is too
rich and the fuel delivery is being reduced. The ECM is de-
creasing the injector pulse width. A value above 128
counts indicates that a lean condition exists for which the
ECM is compensating.
MAP
The Manifold Absolute Pressure (MAP) sensor measures
the change in the intake manifold pressure which results
from engine load and speed changes. As the intake man-
ifold pressure increases, the air density in the intake also
increases and the additional fuel is required.
Misfire History #1–4
Indicates the number of misfires that have occurred after
195 current misfires have been counted. The current mis-
fire counter will add its misfires to the history misfire count-
er after 195 total misfires have taken place. If 1 cylinder is
misfiring, the misfiring current counter will have 195 mis-
fires counted before adding to its history counter. If 2 cylin-
ders are misfiring, the misfiring current counter will add to
their history counters after 97 misfires. The counter incre-
ments only after a misfire diagnostic trouble code (DTC)
has been set.
Front Heated Oxygen Sensor
The pre–converter Front Heated Oxygen Sensor
(HO2S1) reading represents the exhaust oxygen sensor
output voltage. This voltage will fluctuate constantly be-
tween 100 mv (lean exhaust) and 900 mv (rich exhaust)
when the system is operating in a Closed Loop.
Rear Heated Oxygen Sensor
The post–converter Rear Heated Oxygen Sensor
(HO2S2) represents the exhaust oxygen output voltage
past the catalytic converter. This voltage remains inactive,
or the voltage will appear lazy within a range of 100 mv
(lean exhaust) and 900 mv (rich exhaust) when operating
in a Closed Loop.
Short Term FT
The Short Term FT represents a short term correction to
fuel delivery by the ECM in response to the amount of time
the oxygen sensor voltage spends above or below the 450
mv threshold. If the oxygen sensor has mainly been below
450 mv, indicating a lean air/fuel mixture, short term fuel
trim will increase to tell the ECM to add fuel. If the oxygen
sensor voltage stays mainly above the threshold, the ECM
will reduce fuel delivery to compensate for the indicated
rich condition.

ENGINE CONTROLS 1F – 9
DAEWOO V–121 BL4
Spark Advance
This is a display of the spark advance Ignition Coil (IC) cal-
culation which the ECM is programming in the ignition sys-
tem. It computes the desired spark advance using data
such as engine temperature, rpm, engine load, vehicle
speed and operating mode.
TCC Engaged
When the brake pedal is applied, the Torque Converter
Clutch (TCC) brake switch sends a signal to the ECM to
disengage the TCC and disable the cruise control.
Total Misfire Current Counter
Indicates the total number of misfires that have been de-tected in all the cylinders after 100 engine cycles. One
cycle equals one complete 4 stroke cycle. The total misfire
only increments during the steady state cruise conditions.
TP Sensor
The ECM uses the TP Sensor in order to determine the
amount of the throttle demanded by the vehicle’s operator.
The TP Sensor reads between 0.36–0.96 volts at idle to
above 4 volts at WOT.
Vehicle Speed
The vehicle speed sensor signal is converted into mph or
km/h for display. The vehicle speed output from the ECM
is 4000 pulses per mile. The scan tool uses the KWP 2000
serial data from the ECM to obtain vehicle speed, while the
Instrument Panel Cluster (IPC), cruise control module and
the chime alarm module use the 4000 ppm output.

ENGINE CONTROLS 1F – 31
DAEWOO V–121 BL4
TEC (TOOTH ERROR CORRECTION)
LEARN PROCEDURE
When an ECM is reflashed, initialized or replaced, and dri-
veplate of fly wheel has been replaced, follow these proce-
dures to relearn the crankshaft position (CKP) system
variation :
CAUTION : To avoid personal injury when performing
the TEC learn procedure, always set the vehicle park-
ing brake and block the drive wheels. Release the
throttle immediately when the engine starts to decel-
erate. Once the learning procedure is completed, en-
gine control will be learned to the operator, and the
engine will respond to throttle position.1. Stay the gear parking or neutral.
2. Install the scan tool and select ”TEC (Toth Error
Correction) LEARN” menu.
3. Start the engine with A/C off.
4. Keep the engine coolant temperature above 65°C
(149° F)
5. Put the acceleration pedal above 4000 RPM until
the fuel cut–off occurs.
6. Wait 10–15 seconds.
7. Fulfill this procedure again if the scan tool does not
display ”OK” message.
8. Turn the ignition switch OFF.
9. Turn the ignition swtich ON and then clear the DTC
code.

ENGINE CONTROLS 1F – 33
DAEWOO V–121 BL4
On–Board Diagnostic (EOBD) System Check (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition switch to ON.
2. Observe the Malfunction Indicator Lamp (MIL).
Is the MIL illuminate?–Go to Step 2Go to
”No Malfunction
Indicator Lamp”
21. Turn the ignition switch to LOCK.
2. Install the scan tool to the Data link Connector
(DLC).
3. Turn the ignition switch to ON.
4. Attempt to display the Engine Control Module
(ECM) engine data with the scan tool.
Does the scan tool display the ECM engine data?–Go to Step 3Go to Step 8
31. Using the scan tool output test function, select
the MIL lamp control and command the MIL off.
2. Observe the MIL.
Does the MIL turn OFF?–Go to Step 4Go to
”Malfunction In-
dicator Lamp
on Steady”
4Attempt to start the engine.
Does the engine start and continue to run?–Go to Step 5Go to
”Engine Cranks
But Will Not
Run”
5Select DISPLAY DTC with the scan tool.
Are any Diagnostic Trouble Codes (DTCs) stored?–Go to Step 6Go to Step 7
6Check the display for DTCs P0107, P0108, P0113,
P0118, P0122, P0123, P0712, P1392.
Are two or more of the following DTCs stored?–Go to
”Multiple ECM
Information
Sensor DTCs
Set”Go to applica-
ble DTC table
7Compare the ECM data values displayed on the
scan tool to the typical engine scan data values.
Are the displayed values normal or close to the typi-
cal values?–Go to
”ECM Output
Diagnosis”Go to indicated
component
system check
81. Turn the ignition switch to LOCK.
2. Disconnect the ECM connector.
3. Turn the ignition switch to ON.
4. Check the serial data circuit for an open, short
to ground, or short to voltage. Also check the
DLC ignition feed circuit for an open or short to
ground, and check the DLC ground circuits for
an open.
Is a problem found?–Go to Step 9Go to Step 10
9Repair the open, short to ground, or short to voltage
in the serial data circuit or the DLC ignition feed cir-
cuit.
Is the repair complete?–System OK–
101. Attempt to reprogram the ECM.
2. Attempt to display the ECM data with the scan
tool.
Does the scan tool display ECM engine data?–Go to Step 2Go to Step 11
11Replace the ECM.
Is the replacement complete?–System OK–

ENGINE CONTROLS 1F – 35
DAEWOO V–121 BL4
On–Board Diagnostic (EOBD) System Check (1.8L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition switch to ON.
2. Observe the Malfunction Indicator Lamp (MIL).
Is the MIL illuminate?–Go to Step 2Go to
”No Malfunction
Indicator Lamp”
21. Turn the ignition switch to LOCK.
2. Install the scan tool to the Data link Connector
(DLC).
3. Turn the ignition switch to ON.
4. Attempt to display the Engine Control Module
(ECM) engine data with the scan tool.
Does the scan tool display the ECM engine data?–Go to Step 3Go to Step 8
31. Using the scan tool output test function, select
the MIL lamp control and command the MIL off.
2. Observe the MIL.
Does the MIL turn OFF?–Go to Step 4Go to
”Malfunction In-
dicator Lamp
on Steady”
4Attempt to start the engine.
Does the engine start and continue to run?–Go to Step 5Go to
”Engine Cranks
But Will Not
Run”
5Select DISPLAY DTC with the scan tool.
Are any Diagnostic Trouble Codes (DTCs) stored?–Go to Step 6Go to Step 7
6Check the display for DTCs P0107, P0108, P0113,
P0118, P0122, P0123, P0712, P1392.
Are two or more of the following DTCs stored?–Go to
”Multiple ECM
Information
Sensor DTCs
Set”Go to applica-
ble DTC table
7Compare the ECM data values displayed on the
scan tool to the typical engine scan data values.
Are the displayed values normal or close to the typi-
cal values?–Go to
”ECM Output
Diagnosis”Go to indicated
component
system check
81. Turn the ignition switch to LOCK.
2. Disconnect the ECM connector.
3. Turn the ignition switch to ON.
4. Check the serial data circuit for an open, short
to ground, or short to voltage. Also check the
DLC ignition feed circuit for an open or short to
ground, and check the DLC ground circuits for
an open.
Is a problem found?–Go to Step 9Go to Step 10
9Repair the open, short to ground, or short to voltage
in the serial data circuit or the DLC ignition feed cir-
cuit.
Is the repair complete?–System OK–
101. Attempt to reprogram the ECM.
2. Attempt to display the ECM data with the scan
tool.
Does the scan tool display ECM engine data?–Go to Step 2Go to Step 11
11Replace the ECM.
Is the replacement complete?–System OK–

1F – 36IENGINE CONTROLS
DAEWOO V–121 BL4
MULTIPLE ECM INFORMATION SENSOR DTCS SET
Circuit Description
The Engine Control Module (ECM) monitors various sen-
sors to determine engine operating conditions. The ECM
controls fuel delivery, spark advance, transaxle operation,
and emission control device operation based on the sen-
sor 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. The ECM provides the Exhaust Gas Recir-
culation (EGR) Pintle Position Sensor, the Throttle Posi-
tion (TP) sensor, the Manifold Absolute Pressure (MAP)
sensor, and the Fuel Tank Pressure Sensor with a 5 volt
reference and a sensor ground signal. The ECM monitors
the separate feedback signals from these sensors to de-
termine their operating status.
Diagnostic Aids
Be sure to inspect the ECM and the 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 DTCs to be set: P0108,
P0113, P0118, P0123, P1106, P1111, P1115, P1121,
P0463, P0533.
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 ECM and
the splice will cause one or more of the following DTCs to
be set: P0107, P0108, P0113, P0118, P0122, P0123,
P1106, P1111, P1115, P1121, P0462, P0532.
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 following DTCs to be
set: P0107, P0112, P0117, P0122, P1107, P1112, P1114,
P1122, P0462, P0532.Check for the following conditions:
S Inspect for a poor connection at the ECM. Inspect
harness connectors for backed–out terminals, im-
proper mating, broken locks, improperly formed or
damaged terminals, and poor terminal–to–wire con-
nection.
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 (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.
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 ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.

1F – 38IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
10Replace the EGR valve.
Is the replacement complete?–Go to Step 19–
11Locate and repair the short to voltage in the MAP
sensor signal circuit.
Is the repair complete?–Go to Step 19–
12Locate and repair the short to voltage in the TP sen-
sor signal circuit.
Is the repair complete?–Go to Step 19–
13Locate and repair the short to voltage in the IAT sen-
sor signal circuit.
Is the repair complete?–Go to Step 19–
14Locate and repair the short to voltage in the ECT
sensor signal circuit.
Is the repair complete?–Go to Step 19–
15Locate and repair the short to voltage in the EGR
Pintle Position sensor circuit.
Is the repair complete?–Go to Step 19–
16Measure the voltage of the fuel tank pressure sensor
signal circuit between the ECM harness connector
and ground.
Does the voltage near the specified value?0 VGo to Step 18Go to Step 17
17Locate and repair the short to voltage in the fuel tank
pressure sensor signal circuit.
Is the replacement complete?–Go to Step 19–
18Replace the ECM.
Is the repair complete?–Go to Step 19
191. Using the scan tool, clear the Diagnostic
Trouble Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting the DTCs as specified in the supporting
text.
Does the scan tool indicate that this diagnostic ran
and passed?–Go to Step 20Go to Step 2
22Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK