
ENGINE CONTROLS 1F–15
DAEWOO M-150 BL2
made to enter DTC numbers for tests which the diag-
nostic executive does not recognize, the requested in-
formation will not be displayed correctly and the scan
tool may display an error message. The same applies to
using the DTC trigger option in the Snapshot mode. If an
invalid DTC is entered, the scan tool will not trigger.
Failed Last Test
This message display indicates that the last diagnostic
test failed for the selected DTC. For type A, B and E
DTCs, this message will be displayed during subse-
quent ignition cycles until the test passes or DTCs are
cleared. For type C and type D DTCs, this message will
clear when the ignition is cycled.
Failed Since Clear
This message display indicates that the DTC has failed
at least once within the last 40 warm-up cycles since the
last time DTCs were cleared.
Failed This Ig. (Failed This Ignition)
This message display indicates that the diagnostic test
has failed at least once during the current ignition cycle.
This message will clear when DTCs are cleared or the
ignition is cycled.
History DTC
This message display indicates that the DTC has been
stored in memory as a valid fault. A DTC displayed as a
History fault may not mean that the fault is no longer
present. The history description means that all the con-
ditions necessary for reporting a fault have been met
(maybe even currently), and the information was stored
in the control module memory.
MIL Requested
This message display indicates that the DTC is currently
causing the MIL to be turned ON. Remember that only
type A B and E DTCs can request the MIL. The MIL re-
quest cannot be used to determine if the DTC fault con-
ditions are currently being experienced. This is because
the diagnostic executive will require up to three trips dur-
ing which the diagnostic test passes to turn OFF the
MIL.
Not Run Since CI (Not Run Since Cleared)
This message display indicates that the selected diag-
nostic test has not run since the last time DTCs were
cleared. Therefore, the diagnostic test status (passing
or failing) is unknown. After DTCs are cleared, this mes-
sage will continue to be displayed until the diagnostic
test runs.
Not Run This Ig. (Not Run This Ignition)
This message display indicates that the selected diag-
nostic test has not run during this ignition cycle.
Test Ran and Passed
This message display indicates that the selected diag-
nostic test has done the following:Passed the last test.
Run and passed during this ignition cycle.
Run and passed since DTCs were last cleared.
If the indicated status of the vehicle is “Test Ran and
Passed” after a repair verification, the vehicle is ready to
be released to the customer.
If the indicated status of the vehicle is “Failed This Igni-
tion” after a repair verification, then the repair is incom-
plete and further diagnosis is required.
Prior to repairing a vehicle, status information can be
used to evaluate the state of the diagnostic test, and to
help identify an intermittent problem. The technician can
conclude that although the MIL is illuminated, the fault
condition that caused the code to set is not present. An
intermittent condition must be the cause.
PRIMARY SYSTEM-BASED
DIAGNOSTICS
There are primary system-based diagnostics which
evaluate the system operation and its effect on vehicle
emissions. The primary system-based diagnostics are
listed below with a brief description of the diagnostic
function:
Oxygen Sensor Diagnosis
The fuel control oxygen sensor (O2S) is diagnosed for
the following conditions:
Few switch count (rich to lean or lean to rich).
Slow response (average transient time lean to rich or
rich to lean).
Response time ratio (ratio of average transient time
rich(lean) to lean(rich)).
Inactive signal (output steady at bias voltage approxi-
mately 450 mV).
Signal fixed high.
Signal fixed low.
The catalyst monitor heated oxygen sensor (HO2S) is
diagnosed for the following conditions:
Heater performance (current during IGN on).
Signal fixed low during steady state conditions or
power enrichment (hard acceleration when a rich mix-
ture should be indicated).
Signal fixed high during steady state conditions or de-
celeration mode (deceleration when a lean mixture
should be indicated).
Inactive sensor (output steady at approx. 438 mV).
If the O2S pigtail wiring, connector or terminal are dam-
aged, the entire O2S assembly must be replaced. Do
not attempt to repair the wiring, connector or terminals.
In order for the sensor to function properly, it must have
clean reference air provided to it. This clean air refer-
ence is obtained by way of the O2S wire(s). Any attempt
to repair the wires, connector or terminals could result in

1F–16 ENGINE CONTROLS
DAEWOO M-150 BL2
the obstruction of the reference air and degrade the O2S
performance.
Misfire Monitor Diagnostic Operation
The misfire monitor diagnostic is based on crankshaft
rotational velocity (reference period) variations. The En-
gine Control Module (ECM) determines crankshaft rota-
tional velocity using the Crankshaft Position (CKP)
sensor and the Camshaft Position (CMP) sensor. When
a cylinder misfires, the crankshaft slows down momen-
tarily. By monitoring the CKP and CMP sensor signals,
the ECM can calculate when a misfire occurs.
For a non-catalyst damaging misfire, the diagnostic will
be required to monitor a misfire present for between
1000–3200 engine revolutions.
For catalyst-damaging misfire, the diagnostic will re-
spond to misfire within 200 engine revolutions.
Rough roads may cause false misfire detection. A rough
road will cause torque to be applied to the drive wheels
and drive train. This torque can intermittently decrease
the crankshaft rotational velocity. This may be falsely
detected as a misfire.
A rough road sensor, or “G sensor,” works together with
the misfire detection system. The rough road sensor
produces a voltage that varies along with the intensity of
road vibrations. When the ECM detects a rough road,
the misfire detection system is temporarily disabled.
Misfire Counters
Whenever a cylinder misfires, the misfire diagnostic
counts the misfire and notes the crankshaft position at
the time the misfire occurred. These “misfire counters”
are basically a file on each engine cylinder. A current
and a history misfire counter are maintained for each
cylinder. The misfire current counters (Misfire Current
#1–4) indicate the number of firing events out of the last
200 cylinder firing events which were misfires. The mis-
fire current counter will display real time data without a
misfire DTC stored. The misfire history counters (Misfire
Histtory #1–4) indicate the total number of cylinder firing
events which were misfires. The misfire history counters
will display 0 until the misfire diagnostic has failed and a
DTC P0300 is set. Once the misfire DTC P0300 is set,
the misfire history counters will be updated every 200
cylinder firing events. A misfire counter is maintained for
each cylinder.
If the misfire diagnostic reports a failure, the diagnostic
executive reviews all of the misfire counters before re-
porting a DTC. This way, the diagnostic executive re-
ports the most current information.
When crankshaft rotation is erratic, a misfire condition
will be detected. Because of this erratic condition, the
data that is collected by the diagnostic can sometimes
incorrectly identify which cylinder is misfiring.
Use diagnostic equipment to monitor misfire counter
data on EOBD compliant vehicles. Knowing which spe-
cific cylinder(s) misfired can lead to the root cause, evenwhen dealing with a multiple cylinder misfire. Using the
information in the misfire counters, identify which cylin-
ders are misfiring. If the counters indicate cylinders
numbers 1 and 4 misfired, look for a circuit or compo-
nent common to both cylinders number 1 and 4.
The misfire diagnostic may indicate a fault due to a tem-
porary fault not necessarily caused by a vehicle emis-
sion system malfunction. Examples include the following
items:
Contaminated fuel.
Low fuel.
Fuel-fouled spark plugs.
Basic engine fault.
Fuel Trim System Monitor Diagnostic
Operation
This system monitors the averages of short-term and
long-term fuel trim values. If these fuel trim values stay
at their limits for a calibrated period of time, a malfunc-
tion is indicated. The fuel trim diagnostic compares the
averages of short-term fuel trim values and long-term
fuel trim values to rich and lean thresholds. If either val-
ue is within the thresholds, a pass is recorded. If both
values are outside their thresholds, a rich or lean DTC
will be recorded.
The fuel trim system diagnostic also conducts an intru-
sive test. This test determines if a rich condition is being
caused by excessive fuel vapor from the controlled char-
coal canister. In order to meet EOBD requirements, the
control module uses weighted fuel trim cells to deter-
mine the need to set a fuel trim DTC. A fuel trim DTC
can only be set if fuel trim counts in the weighted fuel
trim cells exceed specifications. This means that the ve-
hicle could have a fuel trim problem which is causing a
problem under certain conditions (i.e., engine idle high
due to a small vacuum leak or rough idle due to a large
vacuum leak) while it operates fine at other times. No
fuel trim DTC would set (although an engine idle speed
DTC or HO2S DTC may set). Use a scan tool to observe
fuel trim counts while the problem is occurring.
A fuel trim DTC may be triggered by a number of vehicle
faults. Make use of all information available (other DTCs
stored, rich or lean condition, etc.) when diagnosing a
fuel trim fault.
Fuel Trim Cell Diagnostic Weights
No fuel trim DTC will set regardless of the fuel trim
counts in cell 0 unless the fuel trim counts in the
weighted cells are also outside specifications. This
means that the vehicle could have a fuel trim problem
which is causing a problem under certain conditions (i.e.
engine idle high due to a small vacuum leak or rough
due to a large vacuum leak) while it operates fine at oth-
er times. No fuel trim DTC would set (although an en-
gine idle speed DTC or HO2S DTC may set). Use a
scan tool to observe fuel trim counts while the problem is
occurring.

ENGINE CONTROLS 1F–17
DAEWOO M-150 BL2
DIAGNOSTIC INFORMATION AND PROCEDURES
SYSTEM DIAGNOSIS
DIAGNOSTIC AIDS
If an intermittent problem is evident, follow the guide-
lines below.
Preliminary Checks
Before using this section you should have already per-
formed the “Euro On-Board Diagnostic (EOBD) System
Check.”
Perform a thorough visual inspection. This inspection
can often lead to correcting a problem without further
checks and can save valuable time. Inspect for the fol-
lowing conditions:
Engine Control Module (ECM) grounds for being
clean, tight, and in their proper location.
Vacuum hoses for splits, kinks, collapsing and proper
connections as shown on the Vehicle Emission Con-
trol Information label. Inspect thoroughly for any type
of leak or restriction.
Air leaks at the throttle body mounting area and the
intake manifold sealing surfaces.
Ignition wires for cracks, hardness, proper routing,
and carbon tracking.
Wiring for proper connections.
Wiring for pinches or cuts.
Diagnostic Trouble Code Tables
Do not use the Diagnostic Trouble Code (DTC) tables to
try and correct an intermittent fault. The fault must be
present to locate the problem.
Incorrect use of the DTC tables may result in the unnec-
essary replacement of parts.
Faulty Electrical Connections or Wiring
Most intermittent problems are caused by faulty electri-
cal connections or wiring. Perform a careful inspection
of suspect circuits for the following:
Poor mating of the connector halves.
Terminals not fully seated in the connector body.
Improperly formed or damaged terminals. All connec-
tor terminals in a problem circuit should be carefullyinspected, reformed, or replaced to insure contact
tension.
Poor terminal-to-wire connection. This requires re-
moving the terminal from the connector body.
Road Test
If a visual inspection does not find the cause of the prob-
lem, the vehicle can be driven with a voltmeter or a scan
tool connected to a suspected circuit. An abnormal volt-
age or scan tool reading will indicate that the problem is
in that circuit.
If there are no wiring or connector problems found and a
DTC was stored for a circuit having a sensor, except for
DTC P0171 and DTC P0172, replace the sensor.
Intermittent Malfunction Indicator Lamp
(MIL)
An intermittent Malfunction Indicator Lamp(MIL) with no
DTC present may be caused by the following:
Improper installation of electrical options such as
lights, two way radios, sound, or security systems.
MIL driver wire intermittently shorted to ground.
Fuel System
Some intermittent driveability problems can be attrib-
uted to poor fuel quality. If a vehicle is occasionally run-
ning rough, stalling, or otherwise performing badly, ask
the customer about the following fuel buying habits:
Do they always buy from the same source? If so, fuel
quality problems can usually be discounted.
Do they buy their fuel from whichever fuel station that
is advertising the lowest price? If so, check the fuel
tank for signs of debris, water, or other contamina-
tion.
IDLE LEARN PROCEDURE
Whenever the battery cables, the Engine Control Mod-
ule (ECM), or the fuse is disconnected or replaced, the
following idle learn procedure must be performed:
1. Turn the ignition ON for 10 seconds.
2. Turn the ignition OFF for 10 seconds.

ENGINE CONTROLS 1F–21
DAEWOO M-150 BL2
MULTIPLE ECM INFORMATION SENSOR DTCS SET
Circuit Description
The Engine Control Module (ECM) monitors various
sensors to determine engine operating conditions. The
ECM controls fuel delivery, spark advance, transaxle op-
eration, 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 Cool-
ant Temperature (ECT) sensor, the Intake Air Tempera-
ture (IAT) sensor. The ECM provides the Electric
Exhaust Gas Recirculation (EEGR) Pintle Position Sen-
sor, the Throttle Position (TP) sensor, the Manifold Ab-
solute Pressure (MAP) sensor, and the Fuel Tank
Pressure Sensor with a 5 volt reference and a sensor
ground signal. The ECM monitors the separate feed-
back signals from these sensors to determine their oper-
ating status.
Diagnostic Aids
Be sure to inspect the ECM and the 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 DTCs to be set: P0108,
P0113, P0118, P0123, P1106.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 following
DTCs to be set: P0108, P0113, P0118, P0123, P1106.
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.
Check for the following conditions:
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.
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.

1F–58 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F060
DIAGNOSTIC TROUBLE CODE (DTC) – P0107
MANIFOLD ABSOLUTE PRESSURE SENSOR LOW VOLTAGE
Circuit Description
The engine control module (ECM) uses the Manifold Ab-
solute Pressure (MAP) sensor to control the fuel deliv-
ery and the ignition timing. The MAP sensor measures
the changes in the intake manifold pressure, which re-
sults from engine load (intake manifold vacuum) and the
rpm changes; and converts these into voltage outputs.
The ECM sends a 5 volt-reference voltage to the MAP
sensor. As the manifold pressure changes, the output
voltage of the MAP sensor 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 at idle, while higher
pressure (high voltage) output voltage will be about 4.5
to 5.0 at wide open throttle (WOT). The MAP sensor is
metric pressure, allowing the ECM to make adjustments
for different altitudes.
Conditions for Setting the DTC
This DTC can be stored in “key-on” status.
(Case A)
When the engine idling.
No throttle position(TP) sensor fail conditions pres-
ent.
Engine speed(rpm) is less than 2,500rpm.
The MAP is less than 15kPA.
(Case A)
When the engine part load.
The engine revolution speed is less than 4,000rpm.
No Throttle Position (TP) Sensor fails conditions
present.
The Throttle Position (TP) angle greather than 20.0The MAP is less than 15 kPA.
An open or low voltage condition exists.
Action Taken when the DTC Sets
The Malfunction Indicator Lamp (MIL) will illuminate.
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.
A history DTC is stored.
The coolant fan turns ON.
The ECM will substitutes a fixed MAP value and use
TP to control the fuel delivery (the scan tool will not
show defaulted)
Conditions for Clearing the MIL/DTC
The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm-up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
With the ignition ON and the engine stopped, the man-
ifold pressure is equal to atmosphere pressure and the
signal voltage will be high.
The ECM as an indication of vehicle altitude uses this
information. 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 ±0.4volt.
If a DTC P 0107 is intermittent, refer to “Manifold Abso-
lute Pressure Check” in this Section for further diagno-
sis.

1F–62 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F060
DIAGNOSTIC TROUBLE CODE (DTC) – P0108 MANIFOLD ABSOLUTE
PRESSURE SENSOR HIGH VOLTAGE
Circuit Description
The engine control module (ECM) uses the Manifold Ab-
solute Pressure (MAP) sensor to control the fuel deliv-
ery and the ignition timing. The MAP sensor measures
the changes in the intake manifold pressure, which re-
sults from engine load (intake manifold vacuum) and the
rpm changes; and converts these into voltage outputs.
The ECM sends a 5 volt-reference voltage to the MAP
sensor. As the manifold pressure changes, the output
voltage of the MAP sensor 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 at idle, while higher
pressure (high voltage) output voltage will be about 4.5
to 4.8 at wide open throttle (WOT). The MAP sensor is
metric pressure, allowing the ECM to make adjustments
for different altitudes.
Conditions for Setting the DTC
This DTC can be stored in “key-on” status.
Engine speed is greater than 2,000rpm.
No throttle position sensor (TPS) fail conditions pres-
ent.
The MAP is greater than 600m bar.
A high voltage condition exists.
Action Taken when the DTC Sets
The Malfunction Indicator Lamp (MIL) will illuminate.
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.A history DTC is stored.
The ECM will substitutes a fixed MAP value and use
TP to control the fuel delivery (the scan tool will not
show defaulted)
Conditions for Clearing the MIL/DTC
The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm-up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
With the ignition ON and the engine stopped, the man-
ifold pressure is equal to atmosphere pressure and the
signal voltage will be high.
The ECM as an indication of vehicle altitude uses this
information. 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 ±0.4volt.
If a DTC P 0108 is intermittent, refer to “manifold abso-
lute pressure check” in this Section for further diagnosis.
If the connections are OK monitor the manifold absolute
pressure(MAP) sensor signal voltage while moving re-
lated connectors and the wiring harness. If the failure is
induced, the display on the scan tool will change. This
may help to isolate the location of an intermittent mal-
function.

1F–66 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F100
DIAGNOSTIC TROUBLE CODE (DTC) – P0112 INTAKE AIR TEMPERATURE
SENSOR LOW VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) Sensor uses a therm-
istor to control the signal voltage to the engine control
module (ECM). The ECM supplies a 5 volt reference
voltage and a ground to the sensor. When the air is cold,
the resistance is high ; therefore IAT sensor signal volt-
age will be high. If the intake air is warm, resistance is
low ; therefore the IAT sensor signal voltage will be low.
Conditions for Setting the DTC
The engine rum time is greater than 3 seconds.
IAT voltage is less than 0.01V
Action Taken when the DTC Sets
Emission related.
“Armed” after two trip with a fail.
“Disarmed” after one trip with a pass.
MIL on if failure is detected in three consecutive trips.
Stores a History DTC on the third consecutive with a
fail (The DTC will be armed after the second fail).Stores a Freeze Frame on the third consecutive trip
with a fail (if empty).
The ECM will default to 60°C(140°F)for intake air
temperature. The scan tool will not show the de-
faulted value.
Conditions for Clearing the MIL/DTC
The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic aids
If the vehicle is at ambient temperature, compare the
IAT sensor to the engine coolant temperature(ECT) sen-
sor. The IAT sensor and the ECT sensor should be rela-
tively close to each other. Use the temperature vs.
Resistance Values table to evaluate the possibility of a
skewed sensor. Refer to “Temperature vs. Resistance”
in this Section.

1F–68 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F100
DIAGNOSTIC TROUBLE CODE (DTC) – P0113 INTAKE AIR TEMPERATURE
SENSOR HIGH VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) Sensor uses a therm-
istor to control the signal voltage to the engine control
module (ECM). The ECM supplies a 5 volt reference
voltage and a ground to the sensor . when the air is cold,
the resistance is high ; therefore IAT sensor signal volt-
age will be high. If the intake air is warm, resistance is
low ; therefore the IAT sensor signal voltage will be low.
Conditions for Setting the DTC
The engine rum time is greater than 3 seconds.
IAT voltage is greater than 4.99V.
Action Taken when the DTC Sets
Emission related.
“Armed” after two trip with a fail.
“Disarmed” after one trip with a pass.
MIL on if failure is detected in three consecutive trips.
Stores a History DTC on the third consecutive with a
fail (The DTC will be armed after the second fail).Stores a Freeze Frame on the third consecutive trip
with a fail (if empty).
The ECM will default to last valid value for intake air
temperature. The scan tool will not show the de-
faulted value.
Conditions for Clearing the MIL/DTC
The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up
cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
If the vehicle is at ambient temperature, compare the
IAT sensor to the engine coolant temperature (ECT)
sensor. The IAT sensor and the ECT sensor should be
relatively close to each other.
Use the temperature vs. Resistance Values table to
evaluate the possibility of a skewed sensor. Refer to
“Temperature vs. Resistance” in this Section.