2004 DAEWOO LACETTI Lamp

1F – 274IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0601
ENGINE CONTROL MODULE CHECKSUM ERROR
Circuit Description
The engine control module (ECM) is the control center of
the fuel injection system. It constantly looks at the informa-
tion from various sensors, and controls the systems that
after vehicle performance. The ECM also performs the
diagnostic function of the system. It can recognize opera-
tional problems, alert the driver through the Malfunction In-
dicator Lamp (MIL), and store a Diagnostic Trouble Code
(DTC) or DTCs which identify the problem areas to aid the
technician in making repairs. An electrically erasable pro-
grammable read only memory (EEPROM) is used to
house the program information and the calibrations re-
quired for engine, transaxle, transaxle diagnostics opera-
tion. The ECM uses a value called a checksum for error
detection of the software. The checksum is a value that is
equal to all the numbers in the software added together.
The ECM adds all the values in the software and if that val-
ue does not equal the checksum value, a checksum error
is indicated.Conditions for Setting the DTC
S The ECM detects incorrect checksum.
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
cycle 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.
DTC P0601 – Engine Control Module Checksum 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”
2Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 3–
31. 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 ad specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 4Go to Step 2
4Check 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 – 275
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0604
ENGINE CONTROL MODULE INTERNAL/EXTERNAL RAM
ERROR
Circuit Description
The engine control module (ECM) is the control center of
the fuel injection system. It constantly looks at the informa-
tion from various sensors, and controls the systems that
after vehicle performance. The ECM also performs the
diagnostic function of the system. It can recognize opera-
tional problems, alert the driver through the Malfunction In-
dicator Lamp (MIL), and store a Diagnostic Trouble Code
(DTC) or DTCs which identify the problem areas to aid the
technician in making repairs. An electrically erasable pro-
grammable read only memory (EEPROM) is used to
house the program information and the calibrations re-
quired for engine, transaxle, transaxle diagnostics opera-
tion. The ECM uses a value called a checksum for error
detection of the software. The checksum is a value that is
equal to all the numbers in the software added together.
The ECM adds all the values in the software and if that val-
ue does not equal the checksum value, a checksum error
is indicated.
Conditions for Setting the DTCS The ECM detects an internal or external Random
Acess Memory (RAM) error.
Action Taken When the DTCs 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.
DTC P0604 – Engine Control Module Internal/External RAM 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”
2Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 3–
31. 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 ad specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 4Go to Step 2
4Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
applicable DTC
tableSystem OK

1F – 276IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0605
ENGINE CONTROL MODULE INMVY WRITE ERROR
Circuit Description
The engine control module (ECM) is the control center of
the fuel injection system. It constantly looks at the informa-
tion from various sensors, and controls the systems that
after vehicle performance. The ECM also performs the
diagnostic function of the system. It can recognize opera-
tional problems, alert the driver through the Malfunction In-
dicator Lamp (MIL), and store a Diagnostic Trouble Code
(DTC) or DTCs which identify the problem areas to aid the
technician in making repairs. An electrically erasable pro-
grammable read only memory (EEPROM) is used to
house the program information and the calibrations re-
quired for engine, transaxle, transaxle diagnostics opera-
tion. The ECM uses a value called a checksum for error
detection of the software. The checksum is a value that is
equal to all the numbers in the software added together.
The ECM adds all the values in the software and if that val-
ue does not equal the checksum value, a checksum error
is indicated.Conditions for Setting the DTC
S The ECM detects a INMVY write error.
Action Taken When the DTCs 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.
DTC P0605 – Engine Control Module INMVY Write 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”
2Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 3–
31. 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 ad specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 4Go to Step 2
4Check 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 – 277
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0656
FUEL LEVEL GAUGE CIRCUIT FAULT
Circuit Description
The engine control module(ECM) uses the fuel level input
from the Fuel Level Sensor to calculate expected vapor
pressures within the fuel system. Vapor pressure vary as
the fuel level changes. Vapor pressure is critical in deter-
mining if the evaporative emission (EVAP) system is oper-
ating properly. Fuel Level is also used to determine if the
Fuel level is too high or too low to be able to accurately de-
tect EVAP system faults. This Diagnostic Trouble
Code(DTC) detects a stuck fuel level sender.
Conditions for Setting the DTC
S The fuel tank level output circuit is a short to ground
or a short to battery or an open condition exists.
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.
Diagnostic Aids
Inspect harness connectors for backed–out terminal, im-
proper mating, broken locks, improperly formed or dam-
aged terminals, and poor terminal–to–wire connection.
Inspect the wiring harness for damage.
A stuck Fuel Level Sensor may cause the DTC to set. If
DTC P0656 cannot be duplicated, the information in-
cluded in the Freeze Frame data can be useful in deter-
mining vehicle operating conditions when the DTC was
first set.
Resistance check for the Fuel Level Sensor.
S Empty = 100 ohms or over.
S Half full = about 32.5 ohms.
S Full = 10 ohms or less.

ENGINE CONTROLS 1F – 279
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1181
VARIABLE INTAKE MANIFOLD SOLENOID LOW
VOLTAGE
Circuit Description
The Engine Control Module(ECM) operates a solenoid to
control the Variable Intake Manifold(VIM) solenoid electri-
cal. The solenoid is normally closed. By providing a ground
path, the ECM energizes the solenoid.
Conditions for Setting the DTC
S The VIM solenoid circuit is an open or a short to
ground condition exists.
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. The information will be
stored in the freeze frame and failure records buff-
ers.S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after 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 10 sec-
onds.
Diagnostic Aids
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.

ENGINE CONTROLS 1F – 281
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1182
VARIABLE INTAKE MANIFOLD SOLENOID HIGH
VOLTAGE
Circuit Description
The Engine Control Module(ECM) operates a solenoid to
control the Variable Intake Manifold(VIM) solenoid electri-
cal. The solenoid is normally closed. By providing a ground
path, the ECM energizes the solenoid.
Conditions for Setting the DTC
S The VIM solenoid circuit is a short to battery condi-
tion exists.
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. The information will be
stored in the freeze frame and failure records buff-
ers.S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after 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 10 sec-
onds.
Diagnostic Aids
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.

ENGINE CONTROLS 1F – 283
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1230
FUEL PUMP RELAY LOW VOLTAGE (1.4L DOHC)
Circuit Description
When the ignition switch is turned ON, the ECM will acti-
vate the fuel pump relay and run the in–tank fuel pump.
The fuel pump will operate as long as the engine is crank-
ing or running and the ECM is receiving ignition reference
pulses.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S An open or low voltage condition exists.
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.
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.
Any circuitry, that is suspected as causing the 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 terminals to wire connection
S Physical damage to the wiring harness

1F – 286IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1230
FUEL PUMP RELAY LOW VOLTAGE (1.6L DOHC)
Circuit Description
When the ignition switch is turned ON, the ECM will acti-
vate the fuel pump relay and run the in–tank fuel pump.
The fuel pump will operate as long as the engine is crank-
ing or running and the ECM is receiving ignition reference
pulses.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S An open or low voltage condition exists.
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 Records buffers.
S A history DTC is stored.
S Coolant fan turns ON.
Conditions for Clearing the MIL/DTCS The MIL will turn off after 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 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.
Any circuitry, that is suspected as causing the 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 terminals to wire connection
S Physical damage to the wiring harness