2004 DAEWOO LACETTI Section 6

1F – 242IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0463 – Fuel Level Sensor High Voltage (1.6L DOHC Only)
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to ON.
2. Install a scan tool.
3. Operate the vehicle within Freeze Frame con-
ditions as noted.
Is the Diagnostic Trouble Code (DTC) P0463 set?–Go to Step 3Go to
”Diagnostic
Aids”
31. Disconnect the fuel sender electircal connector
from the fuel pump.
2. Using a digital voltmeter (DVM), measure the
voltage in the signal circuit at terminal 1.
Is the voltage within the specified value?0.2–4.8VGo to Step 4Go to Step 6
4Check for a proper ground connection at the fuel
tank and repair as necessary.
Is a repair necessary?–Go to Step 11Go to Step 5
51. Remove the fuel sender from the fuel tank.
2. Reconnect the fuel pump electrical connector.
3. Monitor the Fuel Level Sensor parameter on
the scan tool while moving the Fuel Level Sen-
sor float from the empty position to the full
position.
4. Repeat the procedure several times.
Does the Fuel Level Sensor value on the scan tool
increase and then decrease steadily when the float
is moved?–Go to
”Diagnostic
Aids”Go to Step 8
6Check for an open or short to battery voltage in the
Fuel Level Sensor circuit and repair as necessary.
Is the repair necessary?–Go to Step 11Go to Step 9
7Repair the open or short to battery voltage in the
Fuel Level Sensor circuit between the Fuel Level
Sensor harness connector and the Fuel Level Sen-
sor.
Is the repair complete?–Go to Step 11–
8Replace the fuel sender assembly.
Is the replacement complete?–Go to Step 11–
91. Connect the fuel sender electrical connector.
2. Disconnect the engine control module(ECM)
connector.
3. Using a digital voltmeter (DVM) measure the
voltage in the signal circuit, at terminal 46.
Does the DVM read within the specified value?0.2–4.8VGo to Step 10Go to
Section 9E, In-
strumentation/
Driver Informa-
tion
10Replace the ECM.
Is the repair complete?–Go to Step 11–

1F – 258IENGINE CONTROLS
DAEWOO V–121 BL4
S Damaged terminals
S Poor terminal to wire connection
S Physical damage to the wiring harness
Ensure the VSS is correctly torqued to the trnasaxle hous-ing.
Refer to ”Intermittents” in this section.
DTC P0501 – Vehicle Speed No Signal (M/T Only)
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
2Notice : Running the vehicle in gear with the wheels
hanging down at full travel will damage the drive
axles.
1. Turn the ignition ON, with the engine OFF.
2. Install a scan tool.
3. Raise the drive wheels.
4. Support the lower control arms so that the
drive axles are in a horizontal (straight) posi-
tion.
5. Allow the engine to idle in gear.
Does the scan tool display vehicle speed above the
specified value?0 mphGo to Step 3Go to Step 4
31. Turn the ignition ON, with the engine OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting this DTC.
Does the scan tool display the vehicle speed above
the specified value?0 mphGo to Step 12Go to Step 4
41. Turn the ignition OFF.
2. Disconnect the engine control module(ECM)
connector 51.
3. Using a digital voltmeter(DVM) connected to
ground, measure the voltage in the Vehicle
Speed Sensor (VSS) signal circuit, at terminal
C while rotating the wheels.
Is the voltage greater than or eqaul to specified val-
ue?0.5VGo to Step 12Go to Step 5
5Measure the resistant in the VSS signal circuit while
rotating the wheels.
Is the resistance greater than the specified value?1950WGo to Step 6Go to Step 7
6Check the VSS signal circuit for an open and repair
as necessary.
Is the repair complete?–Go to Step 12Go to Step 9
7Is the resistance value within or equal to the speci-
fied value?1300–1950WGo to Step 8Go to Step 9
8Check the VSS signal circuit for a short to ground or
for being shorted together and repair as necessary.
Is a repair necessary?–Go to Step 12Go to Step 12
91. Remove the VSS.
2. Measure the resistance between terminals A
and C.
Is the resistance value within the specified value?1300–1950WGo to Step 11Go to Step 10

1F – 260IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0510
THROTTLE POSITION SWITCH CIRCUIT FAULT
(1.4L DOHC)
Circuit Description
The aim of the MTIA(Main Throttle Idle Actuator) is to con-
trol the idle speed with the throttle body itself. The throttle
is motorized for low opening angle (05, 195). The charac-
teristics of the air flow are not the same for low and high
opening angles. As a matter of fact, the gradient of the
mass air flow function of TP sensor is lower for small
angles that permits to be more precise during the idle
speed control. Out of idle speed the throttle is actuated
mechanically by a classical bowdencable.
This switch indicates throttle plate in idle position when
contact closed. This switch is fixed at the DC–motor drive
and the throttle plate closes the contact in dependence to
the actual motor drive position.
Conditions for Setting the DTC
S The engine stopped and ignition switch turned ON.
S DTCs P0122, P0123, P0222 and P0223 are not
set.
S MTIA output signal is highter than throttle position +
2.5° and throttle position is open at least 0.2 sec-
onds.
Or
S DTCs P0122, P0123, P0222, and P0223 are not
set.
S The throttle position output signal is greater than
30° and throttle position is closed at least 2 sec-
onds.
Action Taken When the DTC SetsS The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will store conditions which were present
when the DTC was set as Failure Records data
only.
S This information will not be stored in the Freeze
Frame data.
Conditions for Clearing the MIL/DTC
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
An Intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or wire that is broken
inside the insulation.
VSS signal circuit should be thoroughly checked for the
following conditions
S Backed–out terminals
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal to wire connection
S Physical damage to the wiring harness
Ensure the VSS is correctly torqued to the trnasaxle hous-
ing.
Refer to ”Intermittents” in this section.

1F – 262IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0510
THROTTLE POSITION SWITCH CIRCUIT FAULT
(1.6L DOHC)
Circuit Description
The aim of the MTIA(Main Throttle Idle Actuator) is to con-
trol the idle speed with the throttle body itself. The throttle
is motorized for low opening angle (05, 195). The charac-
teristics of the air flow are not the same for low and high
opening angles. As a matter of fact, the gradient of the
mass air flow function of TP sensor is lower for small
angles that permits to be more precise during the idle
speed control. Out of idle speed the throttle is actuated
mechanically by a classical bowdencable.
This switch indicates throttle plate in idle position when
contact closed. This switch is fixed at the DC–motor drive
and the throttle plate closes the contact in dependence to
the actual motor drive position.
Conditions for Setting the DTC
S The engine stopped and ignition switch turned ON.
S DTCs P0122, P0123, P0222 and P0223 are not
set.
S MTIA output signal is highter than throttle position +
2.5° and throttle position is open at least 0.2 sec-
onds.
Or
S DTCs P0122, P0123, P0222, and P0223 are not
set.
S The throttle position output signal is greater than
30° and throttle position is closed at least 2 sec-
onds.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S Coolant fan turns on.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S Using the scan tool can clear DTC(s).
S Disconnecting the ECM battery feed for 10 sec-
onds.
Diagnostic Aids
An Intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or wire that is broken
inside the insulation.
VSS signal circuit should be thoroughly checked for the
following conditions
S Backed–out terminals
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal to wire connection
S Physical damage to the wiring harness
Ensure the VSS is correctly torqued to the trnasaxle hous-
ing.
Refer to ”Intermittents” in this section.

ENGINE CONTROLS 1F – 337
DAEWOO V–121 BL4
DTC P1628 – Immobilizer No Successful Communication
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan too to the Data Link Connector
(DLC).
3. Turn the ignition ON.
4. Select IMMOBILIZER DIAGNOSIS STATUS
from the scan tool menu.
Is the communication established between the scan
tool and the immobilizer control unit?–Go to Step 3Go to
Section 9T, Im-
mobillzer Anti–
Theft System
31. Turn the ignition OFF.
2. Disconnect the Immobilizer Control Unit and
Engine Control Module (ECM) connectors.
3. Measure the resistance between terminal 7 of
immoblizer control unit and terminal 56 of the
ECM.
Is the resistance within the specified value?0WGo to Step 5Go to Step 4
4Repair an open circuit between terminal 7 of immobi-
lizer control unit and terminal 56 of the ECM.
Is the repair complete?–Go to Step 8–
5Check the terminals in immobilizer control unit and
the ECM for damages and repair as needed.
Is the repair complete?–Go to Step 8Go to Step 6
6Replace the immobilizer control unit.
Is the repair complete?–Go to Step 8Go to Step 7
71. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 8–
81. 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 this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 9Go to Step 2
9Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
applicable DTC
tableSystem OK

ENGINE CONTROLS 1F – 339
DAEWOO V–121 BL4
DTC P1629 – Immobilizer Wrong Computation
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan too to the Data Link Connector
(DLC).
3. Turn the ignition ON.
4. Select IMMOBILIZER DIAGNOSIS STATUS
from the scan tool menu.
Is the communication established between the scan
tool and the immobilizer control unit?–Go to Step 3Go to
Section 9T, Im-
mobillzer Anti–
Theft System
31. Turn the ignition OFF.
2. Disconnect the Immobilizer Control Unit and
Engine Control Module (ECM) connectors.
3. Measure the resistance between terminal 7 of
immoblizer control unit and terminal 56 of the
ECM.
Is the resistance within the specified value?0WGo to Step 5Go to Step 4
4Repair an open circuit between terminal 7 of immobi-
lizer control unit and terminal 56 of the ECM.
Is the repair complete?–Go to Step 8–
5Check the terminals in immobilizer control unit and
the ECM for damages and repair as needed.
Is the repair complete?–Go to Step 8Go to Step 6
6Replace the immobilizer control unit.
Is the repair complete?–Go to Step 8Go to Step 7
71. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 8–
81. 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 this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 9Go to Step 2
9Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
applicable DTC
tableSystem OK

ENGINE CONTROLS 1F – 347
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0106
MANIFOLD ABSOLUTE PRESSURE RATIONALITY
Circuit Description
The Engine Control Module (ECM) uses the Manifold Ab-
solute Pressure (MAP) sensor to control the fuel delivery
and the ignition timing. The MAP sensor measures the
changes in the intake manifold pressure which results
from engine load (intake manifold vacuum) and the rpm
changes, and it converts these into voltage outputs. The
ECM can detect if the MAP sensor is not responding to the
Throttle Position (TP) changes by comparing the actual
MAP change to a predicted MAP change based on the
amount of TP change that occurs. If the ECM does not see
the expected MAP change or more, DTC P0106 will set.
Conditions for Setting the DTC
S Altitude compensated MAP reading is higher than
high threshold or lower than low threshold table
based on rpm and TP signal.
S DTCs P0107, P0108, P0117, P0118, P0122,
P0123, P0201, P0202, P0203, P0204, P0300,
P0351, P0352, P0402, P0404, P1404, P0405,
P0406, P0506, P0507 are not set.
S Engine running.
S Valid Barometric Pressure (BARO) update.
S Torque Converter Clutch (TCC) steady (A/T).
S A/C steady state.
S No TP sensor fail conditions present.
S No MAP fail conditions present.
S Change in Idle Air Control (IAC) is less than 5%.
S Coolant temperature is greater than –10°C (14°F).
S Change in rpm is less than 200.
S Change in TP sensor is less than 3%.
S Change in Exhaust Gas Recirculation (EGR) value
is less than 6%.
S The rpm is between 1300 and 4500.
S All of the above are stabilized for 1.5 seconds.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive ignition cycle with a fail.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S The ECM will substitute a fixed MAP value and use
TP sensor to control the fuel delivery. (The scan
tool will not show defaulted value.)
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.Diagnostic Aids
With the ignition ON and the engine stopped, the manifold
pressure is equal to atmospheric pressure and the signal
voltage will be high. This information is used by the ECM
as an indication of vehicle altitude. Comparison of this
reading with a known good vehicle with the same sensor
is a good way to check the accuracy of a suspect sensor.
Readings should be the same +0.4 volt.
The MAP sensor vacuum source should be thoroughly
checked for restrictions at the intake manifold.
Test Description
Numbers below refer to the step numbers on the Diagnos-
tic 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 occurred. The information is then stored on the
scan tool for later reference.
2. A sensor that displays an ignition ON, engine OFF
BARO value that does not appear normal for the
altitude the vehicle is in should be considered to be
malfunctioning.
3. While starting the engine, the MAP sensor should
detect any changes in the manifold pressure. This
test is to determine if the sensor is stuck at a value.
4. A normal MAP sensor will react as quickly to the
throttle changes as they can be made. A sensor
should not appear to be lazy or catch up with the
throttle movements.
5. This step checks if the reason for no MAP change
was due to a faulty sensor or vacuum source to the
sensor.
6. The MAP sensor vacuum source should be thor-
oughly checked for restrictions. A drill bit can be
used to clean out any casting flash that may exist in
the vacuum port.
7. The MAP sensor vacuum source should be thor-
oughly checked for restrictions. A drill bit can be
used to clean out any casting flash that may exist in
the vacuum port.
9. The MAP Sensor System Performance diagnostic
may have to complete several tests before deter-
mining if the diagnostic has passed or failed the last
test. Operate the vehicle in the Conditions for Set-
ting the DTC several times to ensure that the diag-
nostic runs enough tests to pass or fail.
10. If no faults have been found at this point and no
additional DTCs were set, refer to ”Diagnostic
Aids”in this section for additional checks and infor-
mation.

ENGINE CONTROLS 1F – 349
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0107
MANIFOLD ABSOLUTE PRESSURE LOW VOLTAGE
Circuit Description
The Engine Control Module (ECM) uses the Manifold Ab-
solute Pressure (MAP) sensor to control the fuel delivery
and the ignition timing. The MAP sensor measures the
changes in the intake manifold pressure which results
from engine load (intake manifold vacuum) and the rpm
changes, and it converts these into voltage outputs. The
ECM sends a 5 volt reference voltage to the MAP sensor.
As the manifold pressure changes, the output of MAP sen-
sor also changes. By monitoring the Map sensor output
voltage, the ECM knows the manifold pressure. A low
pressure (low voltage) output voltage will be about 1.0 to
1.5 volts while the higher pressure (high voltage) output
voltage will be about 4.5 to 4.8 volts at Wide Open
Throttle(WOT). The MAP sensor is also used, under cer-
tain conditions to measure Barometric Pressure (BARO),
allowing the ECM to make adjustments for different alti-
tude.
Conditions for Setting the DTC
S MAP is less than 12 kPa (1.7 psi)
S No TP sensor fail conditions present.
S TP sensor is greater than 0% if the rpm is less than
1000.
S TP sensor is greater than 5% if the rpm is greater
than 1000.
S System voltage is between 11.0 and 11.5 volts.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S The ECM will substitute a fixed MAP value and use
TP sensor to control the fuel delivery. (The scan
tool will not show defaulted value.)
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
With the ignition ON and the engine stopped, the manifold
pressure is equal to atmospheric pressure and the signal
voltage will be high. This information is used by the ECM
as an indication of vehicle altitude. Comparison of this
reading with a known good vehicle with the same sensor
is a good way to check the accuracy of a suspect sensor.
Readings should be the same 12 kPa.
If a DTC P0107 is intermittent, refer to ”Manifold Absolute
Pressure Check” in this section for further diagnosis.
Important : After repairs, use the scan tool FUEL TRIM
RESET function to reset long–term fuel trim to 128 (0%).
Test Description
Numbers below refer to the step numbers on the Diagnos-
tic Table.