display DAEWOO LACETTI 2004 Service Manual Online

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 – 312IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
9With a digital voltmeter (DVM) connected to ground,
probe the 5V reference circuit at terminal 1.
Is the voltage measured near the specified value?5VGo to Step 13Go to Step 14
10Check the control circuit for a short to battery voltage
and repair as necessary.
Is a repair necessary?–Go to Step 19Go to Step 12
11Connect the test light to B+ and again probe the con-
trol circuit at terminal 4.
Does the test light illuminate?–Go to Step 15Go to Step 16
12Replace the engine control module (ECM).
Is the replacement complete?–Go to Step 19–
13Check the EGR ground circuit for a poor connection
or proper terminal tension at the ECM and repair as
necessary.
Is a repair necessary?–Go to Step 19Go to Step 17
14Check the 5V reference circuit for a shortage to bat-
tery voltage and repair as necessary.
Is a repair necessary?–Go to Step 19Go to Step 12
15Check the control circuit for a shortage to ground
and repair as necessary.
Is a repair necessary?–Go to Step 19Go to Step 12
16Check the control circuit for an open or poor connec-
tion at the EGR valve electrical connector and repair
as necessary.
Is a repair necessary?–Go to Step 19Go to Step 18
17Replace the EGR valve.
Is the replacement complete?–Go to Step 19–
18Check the ECM electrical connector for a poor con-
nection and repair as necessary.
Is a repair necessary?–Go to Step 19Go to Step 12
191. 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 20Go to Step 2
20Check 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 – 315
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
131. 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 14Go to Step 2
14Check 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 – 317
DAEWOO V–121 BL4
DTC P1511 – Idle Charge Actuator Circuit Fault
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”
2Turn the Turn the ignition switch to ON.
Is the Malfunction Indicator Lamp(MIL) on steady?–Go to Step 4Go to Step 3
31. Connect the scan tool the DLC.
2. Turn the Turn the ignition switch to ON.
Does the scan tool display serial data?–Go to Step 4Try with
another scan
tool
4Start the engine.
Does the engine start?–Go to Step 5Go to
”Engine Cranks
But Will Not
Run”
51. Turn the ignition switch to LOCK.
2. Connect the scan tool to the DLC.
3. Turn the Turn the ignition switch to ON.
Are any Diagnostic Trouble Codes (DTCs) dis-
played?–Go to Step 6Try with
another scan
tool
6Refer to the applicable DTC table.
Is only one DTC identified as valid trouble code
P1511?–Go to Step 7Go to Applica-
ble DTC Table
and Go to
”Multiple DTC”
71. Turn the ignition switch to LOCK.
2. Disconnect the MTIA connector.
3. Disconnect the ECM connector.
4. Measure resistance between MTIA connector
terminal 4 and ECM connector terminal 43.
Does the resistance measure with the value speci-
fied?0WGo to Step 8Go to Step 9
8Measure resistance between MTIA connector termi-
nal 8 and ECM connector terminal 19.
Does the resistance measure within the value speci-
fied?0WGo to Step 10Go to Step 11
91. Repair the wire or the connector terminal as
needed.
S Clear any DTCs from ECM.
S Perform the diagnostic system check.
Is the repair complete?–System OKGo to Step 8
101. Repair the wire or the connector terminal as
needed.
S Clear any DTCs from ECM.
S Perform the diagnostic system check.
Is the repair complete?–System OKGo to Step 11
111. Turn the ignition switch to LOCK.
2. Replace the throttle body assembly.
S Clear any DTCs from ECM.
S Perform the diagnostic system check.
Is the repair complete?–System OKGo to Step 12

1F – 318IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
121. Turn the ignition switch to LOCK.
2. Replace the ECM.
3. Perform the diagnostic system check.
Is the repair complete?–Go to Step 13–
131. 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 this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 14Go to Step 2
14Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 320IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1512 – Idle Charge Actuator Mechanical Error
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”
2Turn the Turn the ignition switch to ON.
Is the Malfunction Indicator Lamp(MIL) on steady?–Go to Step 4Go to Step 3
31. Connect the scan tool the DLC.
2. Turn the Turn the ignition switch to ON.
Does the scan tool display serial data?–Go to Step 4Try with
another scan
tool
4Start the engine.
Does the engine start?–Go to Step 5Go to
”Engine Cranks
But Will Not
Run”
51. Turn the ignition switch to LOCK.
2. Connect the scan tool to the DLC.
3. Turn the Turn the ignition switch to ON.
Are any Diagnostic Trouble Codes (DTCs) dis-
played?–Go to Step 6Try with
another scan
tool
6Refer to the applicable DTC table.
Is only one DTC identified as valid trouble code
P1512?–Go to Step 7Go to Applica-
ble DTC Table
and Go to
”Multiple DTC”
7Check if the accel cable of MTIA is not on accel cable
stop repair the accel cable as necessary.
Is it necessary?–Go to Step 9Go to Step 8
81. Turn the ignition switch to LOCK.
2. Replace the throttle body assembly.
3. Clear any DTCs from ECM.
4. Perform the diagnostic system check.
Is the repair complete?–Go to Step 10–
91. 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 this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 10Go to Step 2
10Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 322IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1513 – Idle Charge Actuator Functional Error
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”
2Turn the Turn the ignition switch to ON.
Is the Malfunction Indicator Lamp(MIL) on steady?–Go to Step 4Go to Step 3
31. Connect the scan tool the DLC.
2. Turn the Turn the ignition switch to ON.
Does the scan tool display serial data?–Go to Step 4Try with
another scan
tool
4Start the engine.
Does the engine start?–Go to Step 5Go to
”Engine Cranks
But Will Not
Run”
51. Turn the ignition switch to LOCK.
2. Connect the scan tool to the DLC.
Turn the Turn the ignition switch to ON.
Are any Diagnostic Trouble Codes (DTCs) dis-
played?–Go to Step 6Try with
another scan
tool
6Refer to the applicable DTC table.
Is only one DTC identified as valid trouble code
P1513?–Go to Step 7Go to Applica-
ble DTC Table
and Go to
”Multiple DTC”
71. Turn the ignition switch to LOCK.
2. Disconnect the MTIA connector.
3. Disconnect the ECM connector.
4. Measure resistance between MTIA connector
terminal 4 and ECM connector terminal 43.
Does the resistance measure with the value speci-
fied?0WGo to Step 8Go to Step 9
8Measure resistance between MTIA connector termi-
nal 8 and ECM connector terminal 19.
Does the resistance measure within the value speci-
fied?0WGo to Step 10Go to Step 11
91. Repair the wire or the connector terminal as
needed.
2. Clear any DTCs from ECM.
3. Perform the diagnostic system check.
Is the repair complete?–System OKGo to Step 8
101. Repair the wire or the connector terminal as
needed.
2. Clear any DTCs from ECM.
3. Perform the diagnostic system check.
Is the repair complete?–System OKGo to Step 11
111. Turn the ignition switch to LOCK.
2. Replace the throttle body assembly.
S Clear any DTCs from ECM.
S Perform the diagnostic system check.
Is the repair complete?–System OKGo to Step 12

ENGINE CONTROLS 1F – 323
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
121. Turn the ignition switch to LOCK.
2. Replace the ECM.
3. Perform the diagnostic system check.
Is the repair complete?–Go to Step 13–
131. 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 this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 14Go to Step 2
14Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 324IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1537
A/C COMPRESSOR RELAY HIGH VOLTAGE
Circuit Description
The A/C system uses an A/C refrigerant pressure sensor
mounted in the high pressure side of the A/C refrigerant
system to monitor A/C refrigerant pressure. The engine
control module (ECM) uses this information to turn ON the
engine coolant fans when the A/C refrigerant pressure is
high and to keep the compressor disengaged when A/C
refrigerant pressure is excessively high or low.
The air conditioning pressure (ACP) sensor operates like
other 3–wire sensors. The ECM applies a 5.0 volt refer-
ence and a sensor ground to the sensor. Changes in the
A/C refrigerant pressure will causes the ACP sensor input
to the ECM to vary. The ECM monitors the ACP sensor
signal circuit and can determine when the signal is out of
the possible range of the sensor. When the signal is out of
range for a prolonged period of time, the ECM will not allow
the A/C compressor clutch to engage. This is done to pro-
tect the compressor.
Conditions for Setting the DTC
S The air conditioning compressor relay circuit is a
short to battery condition exists.
Action Taken When the DTC SetsS 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.
Diagnostic Aids
Inspect harness connectors for backed–out terminals, im-
proper mating, broken locks, improperly formed or dam-
aged terminals, and poor terminal–to–wire connection at
the ECM.
Inspect the wiring harness for damage. If the harness ap-
pears to be OK, observe the A/C pressure display on the
scan tool while moving the connectors and wiring har-
nesses related to the ACP sensor. A change in the A/C
pressure display will indicate the location of the fault.