2003 DAEWOO MATIZ cruise control

ENGINE CONTROLS 1F–7
DAEWOO M-150 BL2
manifold to decrease combustion temperature. The
amount of exhaust gas recirculated is controlled by vari-
ations in vacuum and exhaust back pressure. If too
much exhaust gas enters, combustion will not take
place. For this reason, very little exhaust gas is allowed
to pass through the valve, especially at idle.
The EEGR valve is usually open under the following
conditions:

Warm engine operation.

Above idle speed.
Results of Incorrect Operation
Too much EEGR flow tends to weaken combustion,
causing the engine to run roughly or to stop. With too
much EEGR flow at idle, cruise, or cold operation, any of
the following conditions may occur:

The engine stops after a cold start.

The engine stops at idle after deceleration.

The vehicle surges during cruise.

Rough idle.
If the EEGR valve stays open all the time, the engine
may not idle. Too little or no EEGR flow allows combus-
tion temperatures to get too high during acceleration
and load conditions. This could cause the following con-
ditions:

Spark knock (detonation)

Engine overheating

Emission test failure
INTAKE AIR TEMPERATURE
SENSOR
The Intake Air Temperature (IAT) sensor is a thermistor,
a resistor which changes value based on the tempera-
ture of the air entering the engine. Low temperature pro-
duces a high resistance (100 kohms at –40C [–40F]),
while high temperature causes a low resistance (70
ohms at 130C [266F]).
The Engine Control Module (ECM) provides 5 volts to
the IAT sensor through a resistor in the ECM and mea-
sures the change in voltage to determine the IAT. The
voltage will be high when the manifold air is cold and low
when the air is hot. The ECM knows the intake IAT by
measuring the voltage.
The IAT sensor is also used to control spark timing when
the manifold air is cold.
A failure in the IAT sensor circuit sets a diagnostic
trouble code P0112 or P0113.
IDLE AIR CONTROL VALVE
Notice: Do not attempt to remove the protective cap
and readjust the stop screw. Misadjustment may result
in damage to the Idle Air Control (IAC) valve or to the
throttle body.The IAC valve is mounted on the throttle body where it
controls the engine idle speed under the command of
the Engine Control Module (ECM). The ECM sends volt-
age pulses to the IAC valve motor windings, causing the
IAC valve pintle to move in or out a given distance (a
step or count) for each pulse. The pintle movement con-
trols the airflow around the throttle valves which, in turn,
control the engine idle speed.
The desired idle speeds for all engine operating condi-
tions are programmed into the calibration of the ECM.
These programmed engine speeds are based on the
coolant temperature, the park/neutral position switch
status, the vehicle speed, the battery voltage, and the
A/C system pressure, if equipped.
The ECM “learns” the proper IAC valve positions to
achieve warm, stabilized idle speeds (rpm) desired for
the various conditions (park/neutral or drive, A/C on or
off, if equipped). This information is stored in ECM ”keep
alive” memories (information is retained after the ignition
is turned off). All other IAC valve positioning is calcu-
lated based on these memory values. As a result, en-
gine variations due to wear and variations in the
minimum throttle valve position (within limits) do not af-
fect engine idle speeds. This system provides correct
idle control under all conditions. This also means that
disconnecting power to the ECM can result in incorrect
idle control or the necessity to partially press the accel-
erator when starting until the ECM relearns idle control.
Engine idle speed is a function of total airflow into the
engine based on the IAC valve pintle position, the
throttle valve opening, and the calibrated vacuum loss
through accessories. The minimum throttle valve posi-
tion is set at the factory with a stop screw. This setting
allows enough airflow by the throttle valve to cause the
IAC valve pintle to be positioned a calibrated number of
steps (counts) from the seat during “controlled” idle op-
eration. The minimum throttle valve position setting on
this engine should not be considered the “minimum idle
speed,” as on other fuel injected engines. The throttle
stop screw is covered with a plug at the factory following
adjustment.
If the IAC valve is suspected as being the cause of im-
proper idle speed, refer to “Idle Air Control System
Check” in this section.
MANIFOLD ABSOLUTE PRESSURE
SENSOR
The Manifold Absolute Pressure (MAP) sensor mea-
sures the changes in the intake manifold pressure which
result from engine load and speed changes and con-
verts these to a voltage output.
A closed throttle on engine coast down produces a rela-
tively low MAP output. MAP is the opposite of vacuum.
When manifold pressure is high, vacuum is low. The
MAP sensor is also used to measure barometric pres-
sure. This is performed as part of MAP sensor calcula-

1F–12 ENGINE CONTROLS
DAEWOO M-150 BL2
The enable criteria for each diagnostic is listed on the
first page of the Diagnostic Trouble Code (DTC) descrip-
tion under the heading “Conditions for Setting the DTC.”
Enable criteria varies with each diagnostic and typically
includes, but is not limited to the following items:

Engine speed.

Vehicle speed

Engine Coolant Temperature (ECT)

Manifold Absolute Pressure (MAP)

Barometric Pressure (BARO)

Intake Air Temperature (IAT)

Throttle Position (TP)

High canister purge

Fuel trim

A/C on
Trip
Technically, a trip is a key-on run key-off cycle in which
all the enable criteria for a given diagnostic are met, al-
lowing the diagnostic to run. Unfortunately, this concept
is not quite that simple. A trip is official when all the en-
able criteria for a given diagnostic are met. But because
the enable criteria vary from one diagnostic to another,
the definition of trip varies as well. Some diagnostics are
run when the vehicle is at operating temperature, some
when the vehicle first starts up; some require that the
vehicle cruise at a steady highway speed, some run only
when the vehicle is at idle. Some run only immediately
following a cold engine start-up.
A trip then, is defined as a key-on run-key off cycle in
which the vehicle is operated in such a way as to satisfy
the enable criteria for a given diagnostic, and this diag-
nostic will consider this cycle to be one trip. However,
another diagnostic with a different set of enable criteria
(which were not met) during this driving event, would not
consider it a trip. No trip will occur for that particular
diagnostic until the vehicle is driven in such a way as to
meet all the enable criteria.
Diagnostic Information
The diagnostic charts and functional checks are de-
signed to locate a faulty circuit or component through a
process of logical decisions. The charts are prepared
with the requirement that the vehicle functioned correct-
ly at the time of assembly and that there are not multiple
faults present.
There is a continuous self-diagnosis on certain control
functions. This diagnostic capability is complimented by
the diagnostic procedures contained in this manual. The
language of communicating the source of the malfunc-
tion is a system of diagnostic trouble codes. When a
malfunction is detected by the control module, a DTC is
set, and the Malfunction Indicator Lamp (MIL) is illumi-
nated.
Malfunction Indicator Lamp (MIL)
The Malfunction Indicator Lamp (MIL) is required by
Euro On-Board Diagnostics (EOBD) to illuminate under
a strict set of guidelines.
Basically, the MIL is turned on when the Engine Control
Module (ECM) detects a DTC that will impact the vehicle
emissions.
The MIL is under the control of the Diagnostic Execu-
tive. The MIL will be turned on if an emissions-related
diagnostic test indicates a malfunction has occurred. It
will stay on until the system or component passes the
same test for three consecutive trips with no emissions
related faults.
Extinguishing the MIL
When the MIL is on, the Diagnostic Executive will turn
off the MIL after three consecutive trips that a “test
passed” has been reported for the diagnostic test that
originally caused the MIL to illuminate. Although the MIL
has been turned off, the DTC will remain in the ECM
memory (both Freeze Frame and Failure Records) until
forty (40) warm-up cycles after no faults have been com-
pleted.
If the MIL was set by either a fuel trim or misfire-related
DTC, additional requirements must be met. In addition
to the requirements stated in the previous paragraph,
these requirements are as follows:

The diagnostic tests that are passed must occur with
375 rpm of the rpm data stored at the time the last
test failed.

Plus or minus ten percent of the engine load that was
stored at the time the last test failed. Similar engine
temperature conditions (warmed up or warming up)
as those stored at the time the last test failed.
Meeting these requirements ensures that the fault which
turned on the MIL has been corrected.
The MIL is on the instrument panel and has the following
functions:

It informs the driver that a fault affecting the vehicle’s
emission levels has occurred and that the vehicle
should be taken for service as soon as possible.

As a system check, the MIL will come on with the key
ON and the engine not running. When the engine is
started, the MIL will turn OFF.

When the MIL remains ON while the engine is run-
ning, or when a malfunction is suspected due to a
driveability or emissions problem, an EOBD System
Check must be performed. The procedures for these
checks are given in EOBD System Check. These
checks will expose faults which may not be detected
if other diagnostics are performed first.

1F–242 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F280
DIAGNOSTIC TROUBLE CODE (DTC) – P0501 VEHICLE SPEED NO SIGNAL
(M/T ONLY)
Circuit Description
Vehicle speed information is provided to the engine con-
trol module (ECM) by the voltage speed sensor (VSS) is
a permanent magnet generator that is mounted in the
transaxle and produces a pulsing voltage whenever ve-
hicle speed is over 3 mph (5km/h). The A/C voltage level
and the number of pulses increase with vehicle speed.
The ECM converts the pulsing voltage into mph (km/h)
and than supplies the necessary signal to the instrument
panel for speedometer / odometer operation and to the
cruise control module and multi-function alarm module
operation. The Diagnostic Trouble Code (DTC) will de-
tect if vehicle speed is reasonable according to engine
rpm and load.
Conditions for Setting the DTC

Vehicle speed is not change at least 10 seconds.

Engine speed is greater than 2,100rpm.

MAF is greater than 152mg/tdc.
Action taken when The DTCs 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.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.

Using the scan tool can clear DTC(s).
Diagnostic Aids
An Intermittent problem may be caused by a poor con-
nection, rubbed through wire insulation, or wire that is
broken inside the insulation.
VSS signal circuit should be thoroughly checked for the
following conditions

Backed-out terminals

Improper mating

Broken locks

Improperly formed

Damaged terminals

Poor terminals to wire connection

Physical damage to the wiring harness
Ensure the VSS is correctly torqued to the trnasaxle
housing.
Refer to “intermittents” in this Section.

1F–286 ENGINE CONTROLS
DAEWOO M-150 BL2
SURGES OR CHUGGLES
Definition: Engine power variation under steady throttle
or cruise. Feels like the vehicle speeds up and slows
down with no change in the accelerator pedal position.Important: Make sure the driver understands A/C com-
pressor operation as described in the owner’s manual.
The speedometer reading and the speed reading on the
scan tool should be equal.
Before diagnosing the symptom, check service bulletins
for updates.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
Connect the scan tool to the Data Link Connector
(DLC).
Does the oxygen sensor (O2S) respond quickly to
different throttle positions?
–
Go to Step 4Go to Step 3
3
1. Check the O2S for silicone or other contaminants
from fuel or use of improper Room Temperature
Vulcanizing (RTV) sealant.
2. Replace the contaminated O2S.
Is the repair complete?
–
System OK
–
4
1. Drive the vehicle at the speed of the complaint.
2. Monitor the long term fuel trim reading using the
scan tool.
Is the long term fuel trim reading within the value
specified?
–20–25%Go to Step 7Go to Step 5
5
Is the long term fuel trim reading below the value
specified?
–20%
Go to
“Diagnostic Aids
for DTC P0172”
Go to Step 6
6
Is the long term fuel trim reading above the value
specified?
25%
Go to
“Diagnostic Aids
for DTC P0171”
–
7
Check the fuel system pressure while the condition
exists.
Is the fuel system pressure within specifications?
380 kPa
(55 psi)
Go to Step 8Go to Step 17
8Check the in-line fuel filter.
Is the filter dirty or plugged?–Go to Step 18Go to Step 9
9Perform an injector diagnosis.
Did the injector diagnosis pinpoint the problem?–Go to Step 19Go to Step 10
10
1. Check for proper ignition voltage output using a
spark tester.
2. Inspect the spark plugs for cracks, wear, improper
gap, burned electrodes, or heavy deposits.
Is the problem found?
–
Go to Step 11Go to Step 12
11
Repair or replace any ignition system components
as needed.
Is the repair complete?
–
System OK
–
12
1. Inspect the ECM grounds for being clean, tight,
and in their proper locations.
2. Inspect the vacuum lines for kinks or leaks.
Is the problem found?
–
Go to Step 13Go to Step 14