2004 DAEWOO LACETTI Lamp

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.

1F – 326IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1538
A/C COMPRESSOR RELAY LOW 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 ground an open 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.

1F – 328IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1610
MAIN RELAY HIGH VOLTAGE (1.4L DOHC)
Circuit Description
When the ignition switch to ON, main relay will grounded
to ECM internal ground by ECM controlling.
A system voltage Diagnostic Trouble Code (DTC) will set
whenever the voltage is below a calibrated value.
Conditions for Setting the DTC
S The main relay circuit is a short to battery condition
exists.
Action Taken When the DTCs 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/DTCS 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.
If DTC P1610 cannot be duplicated, reviewing the Fail Re-
cords vehicle mileage since the diagnostic test last failed
may help determine how often the condition that caused
the DTC to set occurs. This may assist in diagnosing the
condition.

1F – 330IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1610
MAIN RELAY HIGH VOLTAGE (1.6L DOHC)
Circuit Description
When the ignition switch to ON, main relay will grounded
to ECM internal ground by ECM controlling.
A system voltage Diagnostic Trouble Code (DTC) will set
whenever the voltage is below a calibrated value.
Conditions for Setting the DTC
S The main relay circuit is a short to battery condition
exists.
Action Taken When the DTCs 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.
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
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.
If DTC P1610 cannot be duplicated, reviewing the Fail Re-
cords vehicle mileage since the diagnostic test last failed
may help determine how often the condition that caused
the DTC to set occurs. This may assist in diagnosing the
condition.

1F – 332IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1611
MAIN RELAY LOW VOLTAGE (1.4L DOHC)
Circuit Description
When the ignition switch to ON, main relay will grounded
to ECM internal ground by ECM controlling.
A system voltage Diagnostic Trouble Code (DTC) will set
whenever the voltage is below a calibrated value.
Conditions for Setting the DTC
S The main relay circuit is a short to ground or an
open condition exists.
Action Taken When the DTCs 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/DTCS 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.
If DTC P1611 cannot be duplicated, reviewing the Fail Re-
cords vehicle mileage since the diagnostic test last failed
may help determine how often the condition that caused
the DTC to set occurs. This may assist in diagnosing the
condition.

1F – 334IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1611
MAIN RELAY LOW VOLTAGE (1.6L DOHC)
Circuit Description
When the ignition switch to ON, main relay will grounded
to ECM internal ground by ECM controlling.
A system voltage Diagnostic Trouble Code (DTC) will set
whenever the voltage is below a calibrated value.
Conditions for Setting the DTC
S The main relay circuit is a short to ground or an
open condition exists.
Action Taken When the DTCs 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.
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
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.
If DTC P1611 cannot be duplicated, reviewing the Fail Re-
cords vehicle mileage since the diagnostic test last failed
may help determine how often the condition that caused
the DTC to set occurs. This may assist in diagnosing the
condition.

1F – 336IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1628
IMMOBILIZER NO SUCCESSFUL COMMUNICATION
Circuit Description
When the ignition switch is turned to ON, the key tested
by immobilizer anti–theft system. While the key code is be-
ing read by immobilizer control unit or integrated anti–theft
control unit, the engine can start run with any key that will
turn the lock cylinder. the key code is read and compared
with key codes that have been stored in the memory of the
immobilizer control unit. If a valid key is detected, the im-
mobilizer control unit sends a serial data release message
to the Engine Control Module (ECM). Included in the re-
lease message is an identification (ID) code which as-
sures that neither the immobilizer control unit nor the ECM
have been substituted to defeat the system. If the ECM re-
ceives an invalid release message, the ECM performs the
following action:
S Disable the fuel injector circuit.
S Disable the fuel pump circuit.
S Disable the ignition coil.
S A Diagnostic Trouble Code (DTC) will stored if de-
tect communication link failure between the ECM
and immobilizer control unit.Conditions for Setting the DTC
S No safety security strategy allowed.
S Time–out delay has elapsed without successful
communication or a transmission key ON/OFF oc-
curred before a successful communication.
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 – 338IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1629
IMMOBILIZER WRONG COMPUTATION
Circuit Description
When the ignition switch is turned to ON, the key tested
by immobilizer anti–theft system. While the key code is be-
ing read by immobilizer control unit or integrated anti–theft
control unit, the engine can start run with any key that will
turn the lock cylinder. the key code is read and compared
with key codes that have been stored in the memory of the
immobilizer control unit. If a valid key is detected, the im-
mobilizer control unit sends a serial data release message
to the Engine Control Module (ECM). Included in the re-
lease message is an identification (ID) code which as-
sures that neither the immobilizer control unit nor the ECM
have been substituted to defeat the system. If the ECM re-
ceives an invalid release message, the ECM performs the
following action:
S Disable the fuel injector circuit.
S Disable the fuel pump circuit.
S Disable the ignition coil.A Diagnostic Trouble Code (DTC) will stored if detect com-
munication link failure between the ECM and immobilizer
control unit.
Conditions for Setting the DTC
S Wrong coded value from ICU.
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.