2004 DAEWOO LACETTI engine controls

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

1F – 304IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
81. Turn the ignition OFF.
2. Disconnect the ECM and check the Wheel
speed sensor signal circuit for high resistance,
an open, a low voltage, or a short to the sensor
ground circuit and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 9
9Check the Wheel speed sensor signal circuit for a
poor connection at the ECM and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 13
10Check for a poor connection at the Wheel speed
sensor and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 11
11Replace the Wheel speed sensor.
Is the repair complete?–Go to Step 14–
121. Turn the ignition OFF.
2. Disconnect the ECM.
3. Turn the ignition ON.
4. Check the Wheel speed sensor signal circuit
for a short to voltage or a short to the 5 volt
reference circuit and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 13
131. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 14–
141. Using the scan tool, clear the 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 ran
and passed?–Go to Step 15Go to Step 2
15Check 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 – 305
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1385
ROUGH ROAD SENSOR CIRCUIT FAULT (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 The VR sensor is greater than 0.06V.
Or
S The minimum value of the VR sensor is less than
1.5V.
OrS The maximum value of the VR sensor is greater
than 2.2V.
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 – 306IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1385 – Rough Road Sensor Circuit Fault (NON 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 P1385.
Does the scan tool indicate that DTC P1385 failed?–Go to Step 4Go to Step 3
31. Check for the following conditions and repair as
needed:
2. VR sensor seal missing or damaged.
3. VR 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 VR sensor electrical connector.
3. Turn the ignition ON, with the engine OFF.
4. Observe the VR sensor value displayed on the
scan tool.
Is the VR sensor value near the specified value?0VGo to Step 5Go to Step 12
51. Jumper the 5 volt reference circuit, terminal C
and the VR sensor signal circuit, terminal 1 to-
gether at the VR sensor harness connector.
2. Observe the VR sensor value 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
VR sensor, or for a poor connection at the ter-
minal 53 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 VR sensor, or a
poor connection at the terminal 84 of the ECM and
repair as needed.
Is the repair complete?–Go to Step 14Go to Step 8
81. Turn the ignition OFF.
2. Disconnect the ECM and check the VR sensor
signal circuit for high resistance, an open, a low
voltage, or a short to the sensor ground circuit
and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 9

ENGINE CONTROLS 1F – 307
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
9Check the VR sensor signal circuit for a poor con-
nection at the ECM and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 13
10Check for a poor connection at terminal 1 of the VR
sensor and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 11
11Replace the VR sensor.
Is the repair complete?–Go to Step 14–
121. Turn the ignition OFF.
2. Disconnect the ECM.
3. Turn the ignition ON.
4. Check the VR sensor signal circuit for a short
to battery voltage or a short to the 5 volt refer-
ence circuit and repair as needed.
Is the repair complete?–Go to Step 14Go to Step 13
131. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 14–
141. Using the scan tool, clear the 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 ran
and passed?–Go to Step 15Go to Step 2
15Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 308IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1402
EXHAUST GAS RECIRCULATION BLOCKED
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 greater than
60°C(140°F).
S Intake Air Temperature(IAT) is greater than
15°C(59°F).
S Manifold Absolute Pressure is greater than 75kPA.
S The EGR is greater than 10%.
S Mass Air Flow is between 71~174mg/tdc.
S Engine Speed Is Between 1,950~2,600rpm.
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0300, P0335,
P0336, P0341, P0342, P1671, P1672, P1673 are
NOT SET.
S EGR is disabled.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.

ENGINE CONTROLS 1F – 309
DAEWOO V–121 BL4
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
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 vehicle 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).
DTC P1402 – Exhaust Gas Recirculation Blocked
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 and allow the engine to idle.
2. Install the scan tool.
3. Command the exhaust gas recirculation (EGR)
valve to the specified values.
Does the engine stall or attempt to stall?50%Go to Step 5Go to Step 3
31. Turn the ignition switch to LOCK.
2. Remove the EGR valve assembly.
3. Inspect the EGR valve, passages and pipe for
a restriction or damage and repair as neces-
sary.
Is a repair necessary?–Go to Step 5Go to Step 4
4Replace the EGR valve.
Is the replacement complete?–Go to Step 5–
51. Start the engine.
2. Disconnect the battery for the specified time.
3. Drive the vehicle to the specified value.
4. Release the throttle and allow the vehicle to
decelerate to the specified value.
Is the EGR Decel Filter Values less than the speci-
fied value?10 secnds
60mph
(27km/h)
20mph
(32km/h)
0mphGo to Step 3Go to Step 6
61. 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 the DTC as specifiec in the supporting
text.
Does the scan tool indicate that this diagnostic ran
and passed?–Go to Step 7Go to Step 2

1F – 310IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1403
EXHAUST GAS RECIRCULATION VALVE FAILURE
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 greater than
60°C(140°F).
S Intake Air Temperature(IAT) is greater than
15°C(59°F).
S Manifold Absolute Pressure is greater than 75kPA.
S The open EGR value is higher than 10%.
S Mass Air Flow is between 71~174mg/tdc.
S Engine Speed Is Between 1,950~2,600rpm.
S EGR potentiometer voltage is less than 0.4V.
S EGR potentiometer voltage is higher than 1.75V or
integral term of EGR controller blocked in high or
low limit.
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0300, P0335,
P0336, P0341, P0342, P1671, P1672, P1673 are
NOT SET.