2004 DAEWOO LACETTI sensor

ENGINE CONTROLS 1F – 553
DAEWOO V–121 BL4
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
1. The On–Board Diagnostic (EOBD) System Checkprompts 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.
DTC P1391 – G Sensor Rough Road Rationality
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–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 P1391.
Does the scan tool indicate that DTC P1391 failed?–Go to Step 4Go to Step 3
3Check for the following conditions and repair as
needed:
S G sensor seal missing or damaged.
S G 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 G sensor electrical connector.
3. Turn the ignition ON, with the engine OFF.
4. Observe the G sensor value displayed on the
scan tool.
Is the G sensor value near the specified value?0 vGo to Step 5Go to Step 12
51. Jumper the 5 volt reference circuit, terminal A
and the G sensor signal circuit, terminal B to-
gether at the G sensor harness connector.
2. Observe the G sensor value displayed on the
scan tool.
Is the G sensor value near the specified value?4.95 vGo to Step 6Go to Step 7
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
G sensor, or for a poor connection at the termi-
nal k34 of the ECM and repair as needed.
3. f the problem is found, repair as necessary.
Is a problem found?–Go to Step 14Go to Step 10
7Check the 5 volt reference circuit for high resistance,
an open between the ECM and the G sensor, or a
poor connection at the terminal k50 of the ECM and
repair as needed.
Is the repair complete?–Go to Step 14Go to Step 8

1F – 554IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
81. Turn the ignition OFF.
2. Disconnect the ECM and check the G sensor
signal circuit for high resistance, an open, a
short to ground, 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 G sensor signal circuit for a poor connec-
tion 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 C of the G
sensor and repair as needed.
Is the repair complete?Go to Step 14Go to Step 11
11Replace the G 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 G 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 – 555
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1392
G SENSOR ROUGH ROAD LOW VOLTAGE
Circuit Description
The Gravity Sensing Rough Road (G) sensor is a vertical
low g–acceleration sensor. By sensing vertical accelera-
tion 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 G sensor detects a rough road condition,
the ECM misfire detection diagnostic will be de–activated.
The G sensor at rest output should be between 2.35–2.65
volts (+1G). During a rough road condition, the voltage
output can vary between 0.5 (–1G) and 4.5 volts (+3G).
Conditions for Setting the DTC
S G sensor output is less than 2%.
S Engine is running more than or equal to 10 sec-
onds.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not 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 A history Diagnostic Trouble Code (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 the harness
connections for backed–out terminals, improper
mating, broken locks, improperly formed or dam-
aged terminals, and poor terminal–to–wire connec-
tion.
S Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the G sensor display on the scan tool while moving
connectors and wiring harnesses related to the sen-
sor. A change in the display will indicate the loca-
tion of the fault.
Since the G sensor shares the ECM 5 volt reference and
ground terminals with the A/C Pressure Sensor, a dam-
aged A/C Pressure Sensor harness or sensor could cause
a G sensor DTC to set. Refer to ”Multiple ECM Information
Sensor DTCs Set” in this section.
The G sensor will give correct voltages only if it is level and
mounted securely to its bracket.
Reviewing the Failure 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.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
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.

1F – 556IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1392 – G Sensor Rough Road Low Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan tool to the Data Link Connector
(DLC).
3. Turn the ignition ON, with the engine OFF.
4. Observe the ROUGH ROAD value displayed
on the scan tool.
Is the ROUGH ROAD value near the specified val-
ue?0 vGo to Step 4Go to Step 3
31. Review and record the scan tool Failure Re-
cords data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using the scan tool, monitor specific Diagnostic
Trouble Code (DTC) info for DTC P1392.
Does the scan tool indicate that DTC P1392 failed?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Disconnect the G sensor electrical connector.
3. Turn the ignition ON, with the engine OFF.
4. Jumper the 5 volt reference circuit, terminal A
and the G sensor signal circuit, terminal B to-
gether at the G sensor harness connector.
5. Observe the G sensor value displayed on the
scan tool.
Is the G sensor value near the specified value?4.95 vGo to Step 9Go to Step 5
51. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM)
and check the 5 volt reference circuit for an
open or short to ground and repair as needed.
Is the repair complete?–Go to Step 11Go to Step 6
6Check the 5 volt reference circuit for poor connection
at the ECM and repair or replace as needed.
Is the repair complete?–Go to Step 11Go to Step 7
71. Turn the ignition OFF.
2. Disconnect the ECM and check the G sensor
signal circuit for an open, a short to ground, or
a short to the sensor ground circuit and repair
as needed.
Is the repair complete?–Go to Step 11Go to Step 8
8Check the G sensor signal circuit for a poor connec-
tion at the ECM and repair as needed.
Is the repair complete?–Go to Step 11Go to Step 10
9Replace the G sensor.
Is the repair complete?–Go to Step 11–
101. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 11–

1F – 558IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1393
G SENSOR ROUGH ROAD HIGH VOLTAGE
Circuit Description
The Rough Road (G) sensor is a vertical low g–accelera-
tion sensor. By sensing vertical acceleration 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 G
sensor detects a rough road condition, the ECM misfire
detection diagnostic will be de–activated. The G sensor at
rest output should be between 2.35–2.65 volts (+1G). Dur-
ing a rough road condition, the voltage output can vary be-
tween 0.5 (–1G) and 4.5 volts (+3G).
Conditions for Setting the DTC
S G sensor output is greater than 98%.
S Engine is running more than or equal to 10 sec-
onds.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not 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 A history Diagnostic Trouble Code (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 the harness
connections for backed–out terminals, improper
mating, broken locks, improperly formed or dam-
aged terminals, and poor terminal–to–wire connec-
tion.
S Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the G sensor display on the scan tool while moving
connectors and wiring harnesses related to the sen-
sor. A change in the display will indicate the loca-
tion of the fault.
Since the G sensor shares the ECM 5 volt reference and
ground terminals with the A/C Pressure Sensor, a dam-
aged A/C Pressure Sensor harness or sensor could cause
a G sensor DTC to set. Refer to”Multiple ECM Information
Sensor DTCs Set” in this section.
The G sensor will give correct voltages only if it is level and
mounted securely to its bracket.
Reviewing the Failure 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.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
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.

ENGINE CONTROLS 1F – 559
DAEWOO V–121 BL4
DTC P1393 – G Sensor Rough Road High Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan tool to the Data Link Connector
(DLC).
3. Start and idle the engine.
4. Observe the ROUGH ROAD value displayed
on the scan tool.
Is the ROUGH ROAD value near the specified val-
ue?4.5 vGo to Step 4Go to Step 3
31. Review and record the scan tool Failure Re-
cords data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using the scan tool, monitor specific Diagnostic
Trouble Code (DTC) info for DTC P1393.
Does the scan tool indicate that DTC P1393 failed?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Disconnect the G sensor electrical connector.
3. Turn the ignition ON, with the engine OFF.
4. Note the G sensor voltage displayed on the
scan tool.
Is the G sensor value near the specified value?0 vGo to Step 5Go to Step 6
5Probe the sensor ground circuit terminal C with a test
light to B+.
Is the test light ON?–Go to Step 7Go to Step 9
6Check the G sensor signal circuit for a short to volt-
age or a short to the 5 volt reference circuit and re-
pair as needed.
Is the repair complete?–Go to Step 12Go to Step 11
7Check for a poor sensor ground terminal connection
at the G sensor electrical connector.
Is the repair complete?–Go to Step 12Go to Step 8
8Check for a poor sensor ground terminal connection
at the Engine Control Module (ECM) and repair as
needed.
Is the repair complete?–Go to Step 12Go to Step 10
9Check the G sensor ground circuit for an open and
repair as needed.
Is the repair complete?–Go to Step 12Go to Step 10
101. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 12–
11Replace the G sensor.
Is the repair complete?–Go to Step 12Go to Step 10

ENGINE CONTROLS 1F – 561
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1396
ABS WSS SIGNAL VARIATION
Circuit Description
The Engine Control Module (ECM) determines linear
wheel speed excessive variation. The wheel speed varia-
tion test detects at least one missing edge from the wheel
speed sensor signal.
Conditions for Setting the DTC
S WSS variation is greater than 18km/h (11.2 mph).
S Vehicle speed is greater than 10km/h (6.2 mph).
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 set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
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 The DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Check for the following conditions:S Poor connection at the ECM – Inspect the harness
connections for backed–out terminals, improper
mating, broken locks, improperly formed or dam-
aged terminals, and poor terminal–to–wire connec-
tion.
S Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the G sensor display on the scan tool while moving
connectors and wiring harnesses related to the sen-
sor. A change in the display will indicate the loca-
tion of the fault.
An open signal circuit of open PWM serial data line be-
tween the ECM and the EBCM will be the cause of this
DTC.
Test Description
The number(s) below refer to specific step(s) on the diag-
nostic table.
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.
6. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.

ENGINE CONTROLS 1F – 563
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1397
ABS WSS NO SIGNAL
Circuit Description
The Engine Control Module (ECM) determines linear
wheel speed fail threshold. The ECM detects a good or
failed wheel speed sensor under power conditions.
Conditions for Setting the DTC
S Vehicle speed is greater than 10km/h (6.2 mph).
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 set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
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 The DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Check for the following conditions:S Poor connection at the ECM – Inspect the harness
connections for backed–out terminals, improper
mating, broken locks, improperly formed or dam-
aged terminals, and poor terminal–to–wire connec-
tion.
S Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the G sensor display on the scan tool while moving
connectors and wiring harnesses related to the sen-
sor. A change in the display will indicate the loca-
tion of the fault.
An open signal circuit of open PWM serial data line be-
tween the ECM and the EBCM will be the cause of this
DTC.
Test Description
The number(s) below refer to specific step(s) on the diag-
nostic table.
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.
6. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.