2004 DAEWOO LACETTI driver

1F – 254IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0481
HIGH SPEED COOLING FAN RELAY CIRCUIT FAULT
(1.6L DOHC)
Circuit Description
Ignition voltage is supplied directly to the cooling fan relay
coil. The engine control module(ECM) controls the relay
by grounding the control circuit via an internal switch called
a driver. The primary function of the driver is supply the
ground for the component being controlled. Each driver
has a fault line which is monitored by the ECM. When the
ECM is commanding a component ON, the voltage of the
control circuit should be low (near 0volts). When the ECM
is commanding the control circuit to a component OFF, the
voltage potential of the circuit should be high(near battery
voltage). If the fault detection circuit senses a voltage oth-
er than what is expected, the fault line status will change
causing the DTC to set.
The relay is used to control the high current flow to the
cooling fan motors. This allows the ECM driver to only
have to handle the relatively low current used by the relay.
Conditions for Setting the DTC
S The high speed cooling fan control circuit is an
open or a short to battery or a short to ground con-
dition exist.
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
Using Freeze Frame and/or failure records data may aid
in locating an intermittent condition. If the DTC cannot be
duplicated, the information included in the Freeze Frame
and/or failure records data can be useful in determining
how many miles since the DTC set. The fail counter and
Pass Counter can also be used to determine how many
ignition cycles the diagnostics reported a Freeze Frame
conditions (rpm, load, vehicle speed, temperature, etc.)
that .are noted. This will isolate when the DTC failed.
DTC P0481 – High Speed Cooling Fan Relay Circuit Fault
(1.6L DOHC)
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. Turn the ignition switch to ON with the engine
OFF.
2. Install a scan tool.
3. Command the relay ON and OFF.
Does the relay turn ON and OFF when command-
ed?–Go to Step 3Go to Step 5
31. Turn the ignition switch to LOCK.
2. Disconnect the engine control module (ECM)
connector.
3. Turn the ignition switch to ON.
4. Using a digital voltmeter(DVM), measure the
current in high speed relay control circuit, at
terminal 9 to ground for 2 minutes.
Does the amperage measure less than the specified
value?0.75 ampsGo to
”Diagnostic
Aids”Go to Step 6

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 – 385
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0135
FRONT HEATED OXYGEN SENSOR (HO2S1) HEATER
CIRCUIT NOT FUNCTIONING
Circuit Description
Heated oxygen sensors (HO2S) are used for fuel control
and post catalyst monitoring. Each HO2S compares the
oxygen content of the surrounding air with the oxygen con-
tent in the exhaust stream. The HO2S must reach operat-
ing temperature to provide an accurate voltage signal. A
heating element inside the HO2S minmizes the time re-
quired for the sensor to reach operating temperature. Volt-
age is provided to the heater by the ignition 1 voltage cir-
cuit through a fuse. With the engine running, ground is
provided to the heater by the HO2S heater low control cir-
cuit, through a low side driver within the engine control
module (ECM). The ECM monitors the current flow
through the heater for diagnosis.
If the ECM detects that the HO2S heater current is above
or blelow a specified range, DTC P0135 seats.
Conditions for Setting the DTC
S DTCs P0106, P0117, P0118, P1017 are not set.
S Engine run time is greater than 200 seconds.
S Filtered O2 heater current is less than 0.025 amps.
Action Taken When the DTC SetsS The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive ignition cycle with a fail.
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 Diagnostic Trouble Code (DTC) is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after three 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.
Diagnostic Aids
An intermittent may be caused by rubbed through wire in-
sulation or a wire contacting the exhaust.
Check for poor connection or damaged harness – inspect
harness connectors for the following conditions:
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection

1F – 408IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0201
INJECTOR 1 CIRCUIT FAULT
Circuit Description
The Engine Control Module (ECM) has four individual in-
jector driver circuits, each of which controls an injector.
When a driver circuit is grounded by the ECM, the injector
is activated. The ECM monitors the current in each driver
circuit. The ECM measures a voltage drop through a fixed
resistor and controls it. The voltage on each driver is moni-
tored to detect a fault. If the voltage is not what the ECM
expects to monitor on the circuit, a Diagnostic Trouble
Code (DTC) is set. This DTC detects a short to ground
and/or an open circuit and short to battery conditions for
low–side drive injector outputs.
Conditions for Setting the DTC
S Monitor fault feedback signal from FETS.
S Engine is in run mode.
S Battery voltage is greater than 9 volts.
S Engine speed is greater than 700 rpm.
S Fault is present for more than 5 seconds.
Action Taken When the DTC Sets
S The ECM will illuminate the Malfunction Indicator
Lamp (MIL) the first time the fault is Detected.S The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
S The ECM will turn off the MIL on the third consecu-
tive trip cycle in which the diagnostic has been run
and the fault is no longer present.
S A history will clear after 40 consecutive warm–up
cycles without a fault.
S DTC can be cleared by using the scan tool Clear
Info function.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
An injector 1 driver circuit that is open or shorted to voltage
will cause a DTC P0201 to set. It will also cause a misfire
due to an inoperative injector. A misfire DTC should also
be set indicating which injector is inoperative.
Long–term and short–term fuel trims that are excessively
high or low are a good indication that an injector is mal-
functioning. Refer to ”Fuel Injector Balance Test” in this
section to check for malfunctioning injectors.

ENGINE CONTROLS 1F – 409
DAEWOO V–121 BL4
The injector resistance tested at the ECM connection is
slightly more than if tested directly at the injector because
it includes resistance of the harness wires. The normal val-
ue is about 13.5 Ω
Test Description
Number(s) below refer to the step number(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. Thiscreates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
3. This step determines if DTC P0201 is the result of
a hard failure or an intermittent condition.
5. This step tests the wiring harness and the ECM
control of the injectors using a test light.
7. This step determines if the circuitry is shorted to
voltage or the ECM is faulty.
9. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.
DTC P0201 – Injector 1 Circuit Fault
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
2Will the engine start?–Go to Step 3Go to
”Engine Cranks
But Will Not
Run”
31. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON, with the engine OFF.
3. Clear the Diagnostic Trouble Codes (DTCs)
using a scan tool.
4. Start the engine and idle for one minute.
Does DTC P0201 reset?–Go to Step 5Go to Step 4
41. Turn the ignition ON, with the engine OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions as noted.
Does DTC P0201 reset?–Go to Step 5Go to
”Diagnostic
Aids”
51. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM)
connector for injector 1.
3. Turn the ignition ON, with the engine OFF.
4. With a test light connected to ground, probe
the driver circuit, terminal M25.
Does the test light illuminate?–Go to Step 7Go to Step 6
6Repair the short to ground or open in the injector
driver circuit.
Is the repair complete?–Go to Step 10–
71. Disconnect the injector 1 wiring connection.
2. With a test light connected to ground, probe
the driver circuit, terminal 1.
Does the test light illuminate?–Go to Step 8Go to Step 9
8Repair the short to voltage in the injector driver cir-
cuit.
Is the repair complete?–Go to Step 10–

ENGINE CONTROLS 1F – 411
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0202
INJECTOR 2 CIRCUIT FAULT
Circuit Description
The Engine Control Module (ECM) has four individual in-
jector driver circuits, each of which controls an injector.
When a driver circuit is grounded by the ECM, the injector
is activated. The ECM monitors the current in each driver
circuit. The ECM measures a voltage drop through a fixed
resistor and controls it. The voltage on each driver is moni-
tored to detect a fault. If the voltage is not what the ECM
expects to monitor on the circuit, a Diagnostic Trouble
Code (DTC) is set. This DTC detects a short to ground
and/or an open circuit and short to battery conditions for
low–side drive injector outputs.
Conditions for Setting the DTC
S Monitor fault feedback signal from FETS.
S Engine is in run mode.
S Battery voltage is greater than 9 volts.
S Engine speed is greater than 700 rpm.
S Fault is present for more than 5 seconds.
Action Taken When the DTC Sets
S The ECM will illuminate the Malfunction Indicator
Lamp (MIL) the first time the fault is Detected.S The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
S The ECM will turn off the MIL on the third consecu-
tive trip cycle in which the diagnostic has been run
and the fault is no longer present.
S A history will clear after 40 consecutive warm–up
cycles without a fault.
S DTC can be cleared by using the scan tool Clear
Info function.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
An injector 2 driver circuit that is open or shorted to voltage
will cause a DTC P0202 to set. It will also cause a misfire
due to an inoperative injector. A misfire DTC should also
be set indicating which injector is inoperative.
Long–term and short–term fuel trims that are excessively
high or low are a good indication that an injector is mal-
functioning. Refer to ”Fuel injector Balance Test” in this
section to check for malfunctioning injectors.