2004 DAEWOO LACETTI Iat

ENGINE CONTROLS 1F – 481
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0406
EXHAUST GAS RECIRCULATION PINTLE POSITION HIGH
VOLTAGE
Circuit Description
An Exhaust Gas Recirculation (EGR) system is used to
lower Nitrogen Oxide (NOx) emission levels caused by
high combustion temperatures. It accomplishes this by
feeding small amounts of exhaust gases back into the
combustion chamber. When the air/fuel mixture is diluted
with the exhaust gases, combustion temperatures are re-
duced
A linear EGR valve is used on this system. The linear EGR
valve is designed to accurately supply exhaust gases to
the engine without the use of intake manifold vacuum. The
valve controls exhaust flow going into the intake manifold
from the exhaust manifold through an orifice with an En-
gine Control Module (ECM) controlled pintle. The ECM
controls the pintle position using inputs from the Throttle
Position (TP) and Manifold Absolute Pressure (MAP) sen-
sors. The ECM then commands the EGR valve to operate
when necessary by controlling an ignition signal through
the ECM. This can be monitored on a scan tool as the De-
sired EGR Position.
The ECM monitors the results of its command through a
feedback signal. By sending a 5 volt reference and a
ground to the EGR valve, a voltage signal representing the
EGR valve pintle position is sent to the ECM. This feed-
back signal can also be monitored on a scan tool and is the
actual position of the EGR pintle. The Actual EGR Position
should always be near the commanded or Desired EGR
Position. This diagnostic Trouble Code (DTC) will detect
short circuit.Conditions for Setting the DTC
S EGR position signal is greater than 98%.
S Ignition voltage is between 11.7 and 16 volts.
S Fail condition last more than 10 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 Diagnostic Trouble Code (DTC) is stored.
S EGR is disabled.
Conditions for Clearing the MIL/DTC
S The MIL will turns 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
Due to moisture associated with exhaust systems, the
EGR valve may freeze and stick in cold weather at times.
After the vehicle is brought into a warm shop for repairs,
the valve warms and the problem disappears. By watching
the Actual EGR and Desired EGR Positions on a cold ve-
hicle with a scan tool, the fault can be easily verified.
Check the freeze frame data to determine if the DTC set
when the vehicle was cold by viewing the Engine Coolant
Temperature (ECT).

1F – 484IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0420
CATALYST OXYGEN SENSOR LOW EFFICIENCY
Circuit Description
In order to control exhaust emissions of Hydrocarbons
(HC), Carbon Monoxide (CO) and Nitrogen Oxide (NOx),
a Three–Way Catalytic Converter (TWC) is used. The cat-
alyst within the converter promotes a chemical reaction
which oxidizes the HC and CO present in the exhaust gas,
converting them into harmless water vapor and carbon
dioxide, it also reduces NOx, converting it into nitrogen.
The catalytic converter also has the ability to store oxygen.
The Engine Control Module (ECM) has the capability to
monitor this process using a Heated
Rear Heated Oxygen Sensor (HO2S2) located in the ex-
haust stream past the TWC. The HO2S2 produces an out-
put signal which indicates the oxygen storage capacity of
the catalyst; this in turn indicates the catalyst’s ability to
convert exhaust emissions effectively. The ECM monitors
the catalyst efficiency by first allowing the catalyst to heat
up, waiting for a stabilization period while the engine is id-
ling, and then adding and removing fuel while monitoring
the reaction of the HO2S2. When the catalyst is function-
ing properly, the HO2S2 response to the extra fuel is slow
compared to the Front Heated Oxygen Sensor (HO2S1).
When the HO2S2 response is close to that of the HO2S1,
the Oxygen storage capability or efficiency of the catalyst
is considered to be bad, and the Malfunction Indicator
Lamp (MIL) will illuminate.
Conditions for Setting the DTC
S Oxygen storage capacity index time is less than 0.3
seconds.
S Before idle test, the vehicle needs to be driven for
at least:
S 15 seconds at airflow is greater than 9.2 g/sec.
for manual transaxle.
S 11 seconds at airflow is greater than 12 g/sec
for automatic transaxle.
S Oxygen Sensor Capacity test condition:
S Closed loop stoichiometry.
S Purge concentration learned.
S Engine is running more than 330 seconds.
S Airflow is between 2.5 and 7.25 g/sec.
S Throttle Position (TP) sensor is less than 1.5%.
S Intake Air Temperature (IAT) is between –7°C
(19.4°F) and 105°C (221°F).
S Barometric pressure (BARO) is greater than 72 kPa
(10.4 psi).
S Catalyst temperature is between 500°C (932°F)
and 850°C (1562°F) for automatic transaxle.
S Catalyst temperature is between 450°C (842°F)
and 850°C (1562°F) for automatic transaxle.
S Closed Loop integrator change is less than 0.03.
S Idle time is less than 1 minute.
S Vehicle speed is less than 3 km/h (1.9 mph).S Block Learn Mode is learned.
S Above condition is stabilized for 5 seconds.
Note : Test is aborted for this idle if:
S Change in engine speed is greater than 80 rpm.
S A/C status changed.
S Cooling fan status changed.
S Insufficient air/fuel shift.
S DTC(s) P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0131, P0132, P0133, P1133,
P0134, P0135, P0137, P0138, P0140, P0141,
P1167, P1171, P0171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0341,
P0342, P0351, P0352, P0402, P0404, P1404,
P0405, P0406, P0443, P0502, P0506, P0507, and
P0562 are not set.
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.
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
The catalyst test may abort due to a change in the engine
load. Do not change the engine load (i.e. A/C, coolant fan,
heater motor) while a catalyst test is in progress.
An intermittent problem may be caused by a poor connec-
tion, rubbed–through wire insulation, or a wire that is bro-
ken inside the insulation.
Any circuitry, that is suspected as causing the intermittent
complaint, 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
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.

1F – 504IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0507
IDLE SPEED RPM HIGHER THAN DESIRED IDLE SPEED
Circuit Description
The Engine Control Module (ECM) controls the air enter-
ing into the engine with an Idle Air Control (IAC) Valve. To
increase the idle rpm, the ECM commands the pintle in-
side the IAC valve away from the throttle body seat. This
allows more air to bypass through the throttle blade. To de-
crease the rpm the ECM commands the pintle towards the
throttle body seat. This reduces the amount of air bypass-
ing the throttle blade. A scan tool will read the IAC valve
pintle position in counts. The higher the counts, the more
air that is allowed to bypass the throttle blade. This Diag-
nostic Trouble Code (DTC) determines if a high idle condi-
tion exists as defined as 200 rpm above the desired idle
rpm.
Conditions for Setting the DTC
S No intrusive tests are active.
S DTC(s) P0106, P0107, P0108, P0112, P0113,
P0117, P0118, P0122, P0123, P0131, P0132,
P0133, P0135, P0141, P1133, P1134, P0171,
P1167, P1171, P0172, P0201, P0202, P0203,
P0204, P0300, P0336, P0337, P0341, P0342,
P0351, P0352, P0402, P0404, P1404, P0405,
P0406, P0441, P0443, and P0502 are not set.
S Engine is running more than 60 seconds.
S Barometric Pressure (BARO) is greater than 72
kPa (10.4 psi).
S Engine Coolant Temperature (ECT) is greater than
60°C (140°F).
S Ignition voltage is between 11 and 16 volts.
S The Intake Air Temperature (IAT) is greater than
–20°C (–4°F).
S IAC valve is controlled fully closed.S All of the above must be met for greater than 5 sec-
onds.
S Idle engine speed error is greater than 200 rpm for
10 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.
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
Inspect the IAC valve electrical connection for proper mat-
ing.
Inspect the wiring harness for damage.
Inspect the throttle stop screw for signs of tampering.
Inspect the throttle linkage for signs of binding or exces-
sive wear.
Inspect the positive crankcase ventilation (PCV) valve and
PCV hose.
A slow or unstable idle may be caused by one of the follow-
ing conditions:

1F – 522IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1106
MANIFOLD ABSOLUTE PRESSURE INTERMITTENT HIGH
VOLTAGE
Circuit Description
The Manifold Absolute Pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum). The
MAP signal voltage to the Engine Control Module (ECM)
varies from below 2 volts at idle (high vacuum) to above
4 volts with the key in the ON position, engine not running
or at Wide Open Throttle (WOT) (low vacuum).
A ”speed density” method of determining engine load is
used. This is calculated using inputs from the MAP sensor,
the rpm (58X), and the Intake Air Temperature (IAT) sen-
sor. The MAP sensor is the main sensor used in this cal-
culation, and measuring engine load is its main function.
The MAP sensor is also used to determine manifold pres-
sure changes while the linear Exhaust Gas Recirculation
(EGR) flow test diagnostic is being run (refer to DTC
P0401). This determines the engine vacuum level for
some other diagnostics and determines Barometric Pres-
sure (BARO). The ECM compares the MAP sensor signal
to calculated MAP based on Throttle Position (TP) and
various other engine load factors. If the ECM detects a
MAP signal voltage that is intermittently above the calcu-
lated value, DTC P1106 will set.
Conditions for Setting the DTC
S The MAP is greater than 103 kPa (15 psi).
S No TP sensor fail conditions present.
S Engine running more than 10 seconds
S TP sensor is less than 15 % if rpm is less than
2500.
S TP sensor less than 35% if rpm is greater than
2500.
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
Check for the following conditions:
S Leaking or plugged vacuum supply line to the MAP
sensor.
S Inspect ECM harness connectors for backed–out
terminals, improper mating, broken locks, improper-
ly formed or damaged terminals, and poor terminal–
towire connection.
S Inspect the wiring harness for damage. If the har-
ness appears to be OK, observe the MAP display
on the scan tool while moving connectors and wir-
ing harnesses related to the sensor. A change in
the display will indicate the location of the fault.
Reviewing the Fail Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

1F – 524IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1107
MANIFOLD ABSOLUTE PRESSURE INTERMITTENT LOW
VOLTAGE
Circuit Description
The Manifold Absolute Pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum). The
MAP signal voltage to the Engine Control Module (ECM)
varies from below 2 volts at idle (high vacuum) to above
4 volts with the key in the ON position, engine not running
or at Wide Open Throttle (WOT) (low vacuum).
A ”speed density” method of determining engine load is
used. This is calculated using inputs from the MAP sensor,
the rpm (58X), and the Intake Air Temperature (IAT) sen-
sor. The MAP sensor is the main sensor used in this cal-
culation, and measuring engine load is its main function.
The MAP sensor is also used to determine manifold pres-
sure changes while the linear Exhaust Gas Recirculation
(EGR) flow test diagnostic is being run (refer to DTC
P0401). This determines the engine vacuum level for
some other diagnostics and determines Barometric Pres-
sure (BARO). The ECM compares the MAP sensor signal
to calculated MAP based on Throttle Position (TP) and
various other engine load factors. If the ECM detects a
MAP signal voltage that is intermittently below the calcu-
lated value, DTC P1107 will set.
Conditions for Setting the DTC
S The MAP is less than 12 kPa (1.7 psi).
S No TP sensor fail conditions present.
S TP sensor is greater than 0% if rpm is less than
1000.
S TP sensor less than 5% if rpm is greater than 1000.
S System voltage is between 11–11.5 volts.
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
Check for the following conditions:
S Leaking or plugged vacuum supply line to the MAP
sensor.
S Inspect ECM harness connectors for backed–out
terminals, improper mating, broken locks, improper-
ly 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 the MAP display
on the scan tool while moving connectors and wir-
ing harnesses related to the sensor. A change in
the display will indicate the location of the fault.
Reviewing the Fail Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

1F – 526IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1111
INTAKE AIR TEMPERATURE INTERMITTENT HIGH
VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the en-
gine. The Engine Control Module (ECM) applies 5 volts
through a pull–up resistor to the IAT sensor. When the in-
take air is cold, the resistance is high, and the ECM will
monitor a high signal voltage on the IAT signal circuit. If the
intake air is warm, the sensor resistance is lower causing
the ECM to monitor a lower voltage. Diagnostic Trouble
Code (DTC) P1111 will set when the ECM detects an inter-
mittent high signal voltage in the intake air temperature
sensor signal circuit or sensor.
Conditions for Setting the DTC
S IAT is less than –38°C (–36°F).
S DTCs P0502, P0117, P0118 are not set
S Engine has been running for over 120 seconds.
S Vehicles speed is less than 25 km/h (16 mph).
S Calculated air flow is less than 15 g/second.
S Engine Coolant Temperature (ECT) is above 70°C
(158°F).
Action Taken When the DTC Sets
S The ECM will substitute a default value for IAT.
S The ECM will store conditions which were present
when the DTC set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.S A history DTC is stored.
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
Check for the following conditions:
S Poor connection at the ECM. Inspect harness con-
nectors for backed–out terminals, improper mating,
broken locks, improperly formed or damaged termi-
nals, and poor terminal–to–wire connection.
S Damaged harness. Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the IAT display on the scan tool while moving con-
nectors and wiring harnesses related to the IAT
sensor. A change in the IAT display will indicate the
location of the fault.
S Reviewing the Fail Records vehicle mileage since
the diagnostic test last failed may help determine
how often the condition that caused the DTC to be
set occurs. This may assist in diagnosing the condi-
tion.
S Use the Temperature vs. Resistance Values table
to evaluate the possibility of a skewed sensor. Re-
fer to ”Temperature vs. Resistance” in this section.

ENGINE CONTROLS 1F – 527
DAEWOO V–121 BL4
Intake Air Temperature Sensor (Temperature Vs. Resistance Value)
°C°FOHMS°C°FOHMS
10021217715594450
801763325417280
60140667–52312300
4511 31188–15521450
35951802–30–2252700
25772796–40–40100700
Above resistance is approximate value
DTC P1111 – Intake Air Temperature Intermittent High Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
3. Request engine Diagnostic Trouble Code
(DTC).
Is DTC P0113 set?–Go to
applicable DTC
tableGo to Step 3
3Is DTC P1115 also set.–Go to Step 7Go to Step 4
4Check for a poor sensor ground circuit terminal 1 at
the Intake Air Temperature (IAT) sensor and repair
as needed.
Is the repair complete?–Go to Step 9Go to Step 5
5Check for a poor sensor signal circuit between termi-
nal 2 of the IAT sensor and terminal M7 of the Engine
Control Module (ECM) for an intermittent open and
repair as needed.
Is the repair complete?–Go to Step 9Go to Step 6
6Check for sensor signal circuit between terminal 2 of
the IAT sensor and terminal M7 of the ECM for an
intermittent short to voltage and repair as needed.
Is the repair complete?–Go to Step 9Go to Step 7
7Check for poor sensor ground circuit terminal M64
at the ECM and repair as needed.
Is the repair complete?–Go to Step 9Go to Step 8
8Check for an intermittent open or a faulty splice in the
sensor ground circuit and repair as needed.
Is the repair complete?–Go to Step 10Go to
”Diagnostic
Aids”

ENGINE CONTROLS 1F – 529
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1112
INTAKE AIR TEMPERATURE INTERMITTENT LOW
VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the en-
gine. The Engine Control Module (ECM) applies 5 volts
through a pull–up resistor to the IAT sensor. When the in-
take air is cold, the resistance is high, and the ECM will
monitor a high signal voltage on the IAT signal circuit. If the
intake air is warm, the sensor resistance is lower causing
the ECM to monitor a lower voltage. Diagnostic Trouble
Code (DTC) P1111 will set when the ECM detects an inter-
mittent high signal voltage in the intake air temperature
sensor signal circuit or sensor.
Conditions for Setting the DTC
S IAT is greater than 149°C (300°F).
S DTC P0502 is not set
S Engine has been running for over two minutes.
S Vehicles speed is greater than 50 km/h (31 mph).
Action Taken When the DTC Sets
S The ECM will substitute a default value for IAT.
S The ECM will store conditions which were present
when the DTC set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S A history DTC is stored.
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
Check for the following conditions:
S Poor connection at the ECM. Inspect harness con-
nectors for backed–out terminals, improper mating,
broken locks, improperly formed or damaged termi-
nals, and poor terminal–to–wire connection.
S Damaged harness. Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the IAT display on the scan tool while moving con-
nectors and wiring harnesses related to the IAT
sensor. A change in the IAT display will indicate the
location of the fault.
S Reviewing the Fail Records vehicle mileage since
the diagnostic test last failed may help determine
how often the condition that caused the DTC to be
set occurs. This may assist in diagnosing the condi-
tion.
S Use the Temperature vs. Resistance Values table
to evaluate the possibility of a skewed sensor. Re-
fer to ”Temperature vs. Resistance” in this section.
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Chart.
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.