2004 DAEWOO LACETTI ignition

1F – 406IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Turn the ignition OFF.
2. Disconnect the Manifold Absolute Pressure
(MAP) sensor electrical connector.
3. Start the engine.
4. Operate the vehicle in Closed Loop while moni-
toring the Long Term Fuel Trim value.
Does the Long Term Fuel Trim value increase above
the specified value?–20%Go to Step 20Go to Step 12
12Check the IAC valve performance. Refer to ”DTC
P0506 Idle Speed RPM Lower Than Desired Idle
Speed” or ”DTC P0507 Idle Speed RPM Higher
Than Desired Idle Speed”in this section and repair
as necessary.
Is the repair complete?–Go to Step 21Go to Step 13
131. Disconnect the vacuum hose from the fuel
pressure regulator and inspect the hose for the
presence of fuel.
2. If fuel is presence in the vacuum hose, replace
the fuel pressure regulator.
Is the repair complete?–Go to Step 21Go to Step 14
141. Turn the ignition ON.
2. Slowly press the acceleration pedal.
Does the Throttle Position (TP) sensor display in-
crease steady and evenly from its minimum voltage
at closed throttle to its maximum voltage at Wide–
Open Throttle (WOT).–Go to Step 15Go to Step 19
151. Perform the Fuel System Diagnosis.
2. If the table isolate a problem, repair as needed.
Is the repair complete?–Go to Step 21Go to Step 16
161. Perform the Evaporative Emission (EVAP)
Control System Diagnosis.
2. If the table isolate a problem, repair as needed.
Is the repair complete?–Go to Step 21Go to Step 17
171. Perform the Fuel Injector Balance Test.
2. If the table isolate a problem, repair as needed.
Is the repair complete?–Go to Step 21Go to Step 18
181. Remove the Front Heated Oxygen Sensor
(HO2S1).
2. Visually/physically inspect the HO2S1 for sili-
cone contamination.
Note : this will be indicated by a powdery white de-
posit on the portion of the HO2S1 exposed to the ex-
haust stream.
1. If contamination is present on the HO2S1, find
the source and repair as needed.
Is the repair complete?–Go to Step 21Go to
”Diagnostic
Aids”
191. Check the TP sensor mounting screws.
2. If they are too loose or missing tighten or re-
place them as needed.
3. If the screws are OK, replace the TP sensor.
Is the repair complete?–Go to Step 21–

ENGINE CONTROLS 1F – 407
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
201. Turn the ignition OFF.
2. Replace the MAP sensor.
Is the repair complete?–Go to Step 21–
211. 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 22Go to Step 2
22Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK

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–

1F – 410IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
91. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 10–
101. 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 has
run and passed?–Go to Step 10Go to Step 2
11Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK

1F – 412IENGINE CONTROLS
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 P0202 – Injector 2 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 P0202 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 P0202 reset?–Go to Step 5Go to
”Diagnostic
Aids”
51. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM)
connector for injector 2.
3. Turn the ignition ON, with the engine OFF.
4. With a test light connected to ground, probe
the driver circuit, terminal M22.
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 2 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 – 413
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
91. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 10–
101. 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 has
run and passed?–Go to Step 10Go to Step 2
11Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK

ENGINE CONTROLS 1F – 415
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 P0203 is the result of
a hard failure or an intermittent condition.
5. This step tests the wiring harness and 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 P0203 – Injector 3 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 P0203 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 P0203 reset?–Go to Step 5Go to
”Diagnostic
Aids”
51. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM)
connector for injector 3.
3. Turn the ignition ON, with the engine OFF.
4. With a test light connected to ground, probe
the driver circuit, terminal M24.
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 3 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–

1F – 416IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
91. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 10–
101. 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 has
run and passed?–Go to Step 10Go to Step 2
11Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK