2004 DAEWOO LACETTI vehicle speed sensor

ENGINE CONTROLS 1F – 199
DAEWOO V–121 BL4
DTC P0327 – Knock Sensor Circuit Fault (1.6L DOHC)
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. Start the engine.
2. Install a scan tool.
3. Clear the Diagnostic Trouble Codes (DTCs).
4. Operate the vehicle within the Freeze Frame
conditions and conditions for setting the DTC
as noted.
Does the Malfunction Indicator (MIL) illuminate?–Go to Step 4Go to Step 3
31. Turn the ignition switch 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 The DTC
as noted.
Does the Malfunction Indicator (MIL) illuminate?–Go to Step 4Go to Step 12
4Listen to the engine while raising and lowering the
engine speed.
Is a knock or audible noise present?–Go to Step 5Go to Step 6
5Repair the mechanical engine problem or a loose
bracket or component.
Is the repair complete?–Go to Step 12–
61. Turn the ignition switch to lock.
2. Disconnect the engine control module(ECM).
3. With a digital voltmeter (DVM) connected to
ground, measure the resistance of the knock
sensor through the knock sensor signal circuit,
terminal 42.
Is the measured value within the specified value?90–100KWGo to Step 7Go to Step 9
7Check for a poor connection at the ECM connector,
knock sensor (KS) signal circuit and repair as neces-
sary.
Is a repair necessary?–Go to Step 12Go to Step 8
8Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 12Go to Step 10
9Check the KS electrical connector for a poor connec-
tion and repair an necessary.
Is a repair necessary?–Go to Step 12Go to Step 10
10Check the KS signal circuit for an open or a low volt-
age or voltage and repair as necessary.
Is a repair necessary?–Go to Step 12Go to Step 11
11Replace the KS.
Is the replacement complete?–Go to Step 12–

1F – 218IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0400
EXHAUST GAS RECIRCULATION OUT OF LIMIT
Circuit Description
An Exhaust Gas Re–circulation (EGR) system is used to
lower oxides of nitrogen (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 a engine
control module(ECM) controlled pintle. The ECM controls
the pintle position using inputs from the Throttle Position
(TP) and the Manifold Absolute Pressure (MAP) sensor.
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 Desired
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 an open or
short circuit.
Conditions for Setting the DTC
S The vehicle is part load.
S The engine controls system is in closed loop.
S Engine Coolant Temperature (ECT) is higher than
70°C (158°F). (1.4L DOHC)
S Engine Coolant Temperature (ECT) is higher than
60°C (140°F). (1.6L DOHC)
S Mass Air Flow is between 120~230mg/tdc.
(1.4L DOHC)
S Mass Air Flow is between 71~174mg/tdc.
(1.6L DOHC)
S Engine Speed is Between 1,800~2,400rpm.
(1.4L DOHC)
S Engine Speed is Between 1,950~2,600rpm.
(1.6L DOHC)
S Intake Air Temperature(IAT) is higher than
15°C(59°F).
S Manifold Absolute Pressure is greater than 75kPA.
S The EGR is higher than 10%.

1F – 230IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0420
CATALYST 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 Oxygen Sensor
(HO2S) located in the exhaust stream past the TWC. The
HO2S produces an output signal which indicates the oxy-
gen storage capacity of the catalyst; this in turn indicates
the catalyst’s ability to convert exhaust emissions effec-
tively. The ECM monitors the catalyst efficiency by first al-
lowing the catalyst to heat up, waiting for a stabilization pe-
riod while the engine is idling, and then adding and
removing fuel while monitoring the reaction of the HO2S.
When the catalyst is functioning properly, the HO2S re-
sponse to the extra fuel is slow compared to the Oxygen
Sensor (O2S). When the HO2S response is close to that
of the O2S, 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 Closed loop stoichiometry.
S Engine Coolant Temperature (ECT) is more than
75°C (167°F) . (1.4L DOHC)
S Engine Coolant Temperature (ECT) is more than
70°C (158°F) . (1.6L DOHC)
S Engine speed between 1,766rpm and 2,368rpm.
(1.4L DOHC)
S Engine speed between 1,760rpm and 2,530rpm.
(1.6L DOHC)
S Vehicle speed is between 47km/h (29.2mph) and
80km/h (49.7mph). (1.4L DOHC)
S Vehicle speed is between 60km/h (37.3mph) and
76km/h (47.2mph). (1.6L DOHC)
S The manifold absolute pressure is greater than 70
kpa. (1.4L DOHC)S The manifold absolute pressure is greater than 76
kpa. (1.6L DOHC)
S Activity of the heated oxygen sensor excited by
lambda controller stimuli higher than a threshold.
S DTC(s) P0107, P0108, P0117, P0118, P0122,
P0123, P0131, P0132, P0133, P0137, P0138,
P0140, P0141, P0171, P0172, P0300, P0336,
P0337, P0341, P0342, P0351, P0352, P0404,
P0405, P0405 and P0562 are not sets.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. 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.

ENGINE CONTROLS 1F – 257
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0501
VEHICLE SPEED NO SIGNAL (M/T ONLY)
Circuit Description
Vehicle speed information is provided to the engine control
module (ECM) by the voltage speed sensor (VSS) is a per-
manent magnet generator that is mounted in the transaxle
and produces a pulsing voltage whenever vehicle speed
is over 3 mph (5km/h). The A/C voltage level and the num-
ber of pulses increase with vehicle speed. The ECM con-
verts the pulsing voltage into mph (km/h) and than sup-
plies the necessary signal to the instrument panel for
speedometer/ odometer operation and to the cruise con-
trol module and multi–function alarm module operation.
The Diagnostic Trouble Code (DTC) will detect if vehicle
speed is reasonable according to engine rpm and load.
Conditions for Setting the DTC
S Vehicle speed is not change at least 25 seconds.
S Engine speed is greater than 2,500rpm.
S MAF is greater than 180mg/tdc.
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

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

ENGINE CONTROLS 1F – 299
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1382
ROUGH ROAD DATA INVALID (NON ABS)
Circuit Description
The VR sensor is used to detecting the road situation.
By sensing difference of wheel rotation duration caused by
bumps or potholes in the road, the Engine Control Module
(ECM) can determine if the changes in crankshaft speed
are due to engine misfire or are driveline induced. If the VR
sensor detects a rough road condition, the ECM misfire
detection diagnostic will be de–activated.
Conditions for Setting the DTC
S Vehicle speed is higher than 5km/h(3.1mph).
S No Vehicle Speed Sensor error not set.
S VR sensor output signal is higher than 0.26.
S VR sensor output signal is not change for 30sec-
onds.Action Taken When the DTC Sets
S 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.

1F – 302IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1382
ROUGH ROAD DATA INVALID (ABS)
Circuit Description
The wheel speed sensor is used to detecting the road situ-
ation.
As the wheel is rotated, the wheel speed sensor produces
an AC voltage that increase with wheel speed. The EBCM
uses the frequency of the AC signal to calculate wheel
speed. The wheel speed sensor is connected to EBCM by
a ”twisted pair” of wires. Twisting reduces noise suscepti-
bility than may cause a DTC to set. If the wheel speed sen-
sor detects a rough road condition, the ECM misfire detec-
tion diagnostic will be de–activated.
Conditions for Setting the DTC
S Vehicle speed is higher than 5km/h(3.1mph).
S No Vehicle Speed Sensor error not set.
S VR sensor output signal is higher than 0.26.S VR sensor output signal is not change for 30sec-
onds.
Action Taken When the DTC Sets
S 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.

ENGINE CONTROLS 1F – 303
DAEWOO V–121 BL4
DTC P1382 – Rough Road Data Invalid (ABS)
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition ON, with engine OFF.
2. Install a scan tool to the Data Link Connector
(DLC).
3. Review and record the scan tool Failure Re-
cords data.
4. Operate the vehicle within Failure Records
conditions as noted.
5. Using the scan tool, monitor specific Diagnostic
Trouble Code (DTC) info for DTC P1382.
Does the scan tool indicate that DTC P1382 failed?–Go to Step 4Go to Step 3
31. Check for the following conditions and repair as
needed:
2. Wheel speed sensor seal missing or damaged.
3. Wheel speed sensor mounting flanges
cracked, missing, or incorrectly installed.
Is the repair complete?–Go to Step 14Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Disconnect the defected Wheel speed sensor
electrical connector.
3. Turn the ignition ON, with the engine OFF.
4. Observe the Wheel speed sensor value dis-
played on the scan tool.
Is the Wheel speed sensor value near the specified
value?0VGo to Step 5Go to Step 12
51. Jumper the 5 volt reference circuit, the Wheel
speed sensor signal circuit, together at the de-
fected Wheel speed sensor harness connector.
2. Observe the defected Wheel speed sensor val-
ue displayed on the scan tool.
Is the VR sensor value near the specified value?4.95VGo to Step 14Go to Step 10
61. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM)
and check the sensor ground circuit for high
resistance, an open between the ECM and the
Wheel speed sensor, or for a poor connection
of the ECM and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 10
7Check the 5 volt reference circuit for high resistance,
an open between the ECM and the Wheel speed
sensor, or a poor connection of the ECM and repair
as needed.
Is the repair complete?–Go to Step 14Go to Step 8