check engine light DAEWOO LACETTI 2004 Service Owner's Manual

ENGINE CONTROLS 1F – 51
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
471. Disconnect the vacuum line from the fuel pres-
sure regulator.
2. Inspect the vacuum line for the presence of
fuel.
3. Inspect the fuel pressure regulator vacuum port
for the presence of fuel.
Is any fuel presen–Go to Step 50Go to Step 51
48Check the fuel for contamination.
Is the fuel contaminated?–Go to Step 49Go to Step 65
491. Remove the contaminated fuel from the fuel
tank.
2. Clean the fuel tank as needed.
Is the repair complete?–Go to Step 3–
50Replace the fuel pressure regulator.
Is the repair complete?–Go to Step 3–
511. Remove the fuel pump assembly from the fuel
tank.
2. Inspect the fuel pump sender and the fuel cou-
pling hoses for a restriction.
3. Inspect the in–tank fuel filter for a restriction.
Is the problem found?–Go to Step 52Go to Step 43
52Replace the fuel pump sender, the in–tank fuel filter,
and/or the fuel coupling hoses as needed.
Is the repair complete?–Go to Step 3–
531. Turn the ignition OFF.
2. Disconnect the electrical connector at the fuel
pump.
3. Connect a test light between the fuel pump
connector terminal 3 and a known good
ground.
4. Turn the ignition ON.
5. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 54Go to Step 55
54Repair the open wire between the fuel pump connec-
tor terminal 2 and ground.
Is the repair complete–Go to Step 3–
551. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 85 and ground.
4. Turn the ignition ON.
Is the test light on?2 secGo to Step 56Go to Step 62
561. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 86 and battery posi-
tive.
3. Turn the ignition ON.
4. With the ignition ON, the test light should light
for the time specified.
Is the test light on?–Go to Step 57Go to Step 61

1F – 52IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
571. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light on?–Go to Step 58Go toStep 63
581. Turn the ignition OFF.
2. Check the wire between the fuel pump relay
connector terminal 87 and the fuel pump con-
nector terminal 3 for an open or short to
ground.
Is the repair complete?–Go to Step 2–
59Replace the fuel pump relay.
Is the repair complete?–Go to Step 3–
601. Check for an open in the wiring between the
fuel pump relay connector terminal 86 and
ground.
Is the problem found?–Go to Step 71–
61Check the wire between the fuel pump relay connec-
tor terminal 85 to the ECM connector terminal K54
for an open.
Is the problem found?–Go to Step 62Go to Step 40
62Repair the wire between the fuel pump relay connec-
tor terminal 85 to the ECM connector terminal K54.
Is the repair complete?–Go to Step 3–
63Repair the wire between the fuel pump relay connec-
tor terminal 30 and the fuse Ef18.
Is the repair complete?–Go to Step 3–
641. Turn the ignition OFF.
2. Disconnect the fuel injector harness connectors
from all of the fuel injectors.
3. Turn the ignition ON.
4. Connect a test light between the fuel injector
harness connector 2 and ground.
5. Repeat step 4 for each of the remaining fuel
injectors.
Is the test light on at all of the fuel injectors?–Go to Step 65Go to Step 68
651. Turn the ignition OFF.
2. Connect a test light between the fuel injector
harness connector terminal 1 and battery posi-
tive.
3. Crank the engine.
4. Repeat steps two and three for each of the re-
maining fuel injectors.
Does the test light flash for all of the fuel injectors?–Go to Step 66Go to Step 69
66Measure the resistance of each fuel injector.
Is the resistance within the value specified (the re-
sistance will increase slightly at higher tempera-
tures)?11.6–12.4 WSystem OKGo to Step 67
67Replace any of the fuel injectors with a resistance
out of specification.
Is the repair complete?–Go to Step 3–

ENGINE CONTROLS 1F – 55
DAEWOO V–121 BL4
No Malfunction Indicator Lamp (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
1Attempt to start the engine.
Does the engine start?–Go to Step 2Go to
”Engine Cranks
But Will Not
Run”
21. Turn the ignition switch to LOCK.
2. Disconnect the Engine Control Module (ECM)
connector.
3. Turn the ignition switch to ON.
4. Connect a test light between the ECM connec-
tor terminal 39 and ground.
Is the test light illuminate?–Go to Step 3Go to Step 6
3Check terminals for damage or poor connection.
Does any problem found?–Go to Step 5Go to Step 4
4Replace the ECM.
Is the replacement complete?–Go to
”On–Board
Diagnostic Sys-
tem Check”–
5Repair any damaged terminals or poor connection.
Is the repair complete?–Go to
”On–Board
Diagnostic Sys-
tem Check”–
6Check the fuse F4.
Is the fuse open?Go to Step 7Go to Step 8
71. Check for a short to ground in the circuit and
repair as needed.
2. Replace the fuse F4.
Is the repair or replacement complete?–Go to
”On–Board
Diagnostic Sys-
tem Check”–
81. Check for an open circuit between fuse F4 and
the ECM connector terminal 39 and repair as
needed.
2. Check the MIL bulb and replace if open.
Is the repair or replacement complete?–Go to
”On–Board
Diagnostic Sys-
tem Check”–

1F – 56IENGINE CONTROLS
DAEWOO V–121 BL4
NO MALFUNCTION INDICATOR LAMP (1.8L DOHC)
Circuit Description
When the ignition is turned ON, the Malfunction Indicator
Lamp (MIL) will be turned ON and remain ON until the en-
gine is running, if no Diagnostic Trouble Codes (DTCs) are
stored. Battery voltage is supplied through the ignition
switch directly to the MIL telltale. The Engine Control Mod-
ule (ECM) controls the MIL by providing a ground path
through the MIL control circuit to turn ON the MIL.
Diagnostic Aids
An open ignition fuse F4 will cause the entire cluster to be
inoperative.
Check the battery and ignition feed circuits for poor con-
nections if the MIL is intermittent.Any circuitry, that is suspected as causing an intermittent
complaint, should be thoroughly checked for backed–out
terminals, improper mating, broken locks, improperly
formed or damaged terminals, poor terminal–to–wiring
connections or physical damage to the wiring harness.
Test Description
Number(s) below refer to the step(s) on the diagnostic
table.
1. If the engine fails to start and the MIL is inopera-
tive, then the fault can be isolated to either the
ECM ignition feed. The battery feed, or a poor
ground at the engine block, or the ECM.
2. Probing the MIL circuit with a test light to ground
stimulates the ECM’s control of the MIL. If the MIL
illuminates, then the malfunction can be isolated to
the control of the MIL or a poor connection at the
MIL terminal to the ECM.

ENGINE CONTROLS 1F – 57
DAEWOO V–121 BL4
No Malfunction Indicator Lamp (1.8L DOHC)
StepActionValue(s)YesNo
1Attempt to start the engine.
Does the engine start?–Go to Step 2Go to
”Engine Cranks
But Will Not
Run”
21. Turn the ignition switch to LOCK.
2. Disconnect the Engine Control Module (ECM)
connector.
3. Turn the ignition switch to ON.
4. Connect a test light between the ECM connec-
tor terminal K64 and ground.
Is the test light illuminate?–Go to Step 3Go to Step 6
3Check terminals for damage or poor connection.
Does any problem found?–Go to Step 5Go to Step 4
4Replace the ECM.
Is the replacement complete?–Go to
”On Board
Diagnostic Sys-
tem Check”–
5Repair any damaged terminals or poor connection.
Is the repair complete?–Go to
”On Board
Diagnostic Sys-
tem Check”–
6Check the fuse F4.
Is the fuse open?Go to Step 7Go to Step 8
71. Check for a short to ground in the circuit and
repair as needed.
2. Replace the fuse F4.
Is the repair or replacement complete?–Go to
”On Board
Diagnostic Sys-
tem Check”
81. Check for an open circuit between fuse F4 and
the ECM connector terminal K64 and repair as
needed.
2. Check the MIL bulb and replace if open.
Is the repair or replacement complete?–Go to
”On Board
Diagnostic Sys-
tem Check”–

1F – 66IENGINE CONTROLS
DAEWOO V–121 BL4
Fuel Pump Relay Circuit Check (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition OFF for 10 seconds.
2. Turn the ignition ON.
3. Listen for in–tank fuel pump operation.
Does the fuel pump operate for the time specified?2 secSystem OKGo to Step 2
21. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Turn the ignition ON. Is the test light on?–Go to Step 3Go to Step 8
31. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 86 and battery posi-
tive.
3. Turn the ignition ON.
4. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 4Go to Step 9
41. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light on?–Go to Step 5Go to Step 11
5Check for an open or short to ground in the wire be-
tween the fuel pump relay connector terminal 87 and
the fuel pump connector terminal 3.
Is the problem found?–Go to Step 6Go to Step 7
61. Repair the wire between the fuel pump relay
connector terminal 87 and the fuel pump con-
nector terminal 3.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
71. Replace the fuel pump relay.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
8Check for an open wire between the fuel pump relay
connector terminal 30 and the battery.
Is the problem found?–Go to Step 13–
9Check for an open wire between the fuel pump relay
connector terminal 86 to the engine control module
(ECM) connector terminal 6.
Is the problem found.–Go to Step 10Go to Step 12
101. Repair the wire between the fuel pump relay
connector terminal 86 to the ECM connector
terminal 6.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–

ENGINE CONTROLS 1F – 69
DAEWOO V–121 BL4
Fuel Pump Relay Circuit Check (1.8L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition OFF for 10 seconds.
2. Turn the ignition ON.
3. Listen for in–tank fuel pump operation.
Does the fuel pump operate for the time specified?2 secSystem OKGo to Step 2
21. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Turn the ignition ON. Is the test light on?–Go to Step 3Go to Step 8
31. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 85 and battery posi-
tive.
3. Turn the ignition ON.
4. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 4Go to Step 9
41. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light on?–Go to Step 5Go to Step 11
5Check for an open or short to ground in the wire be-
tween the fuel pump relay connector terminal 87 and
the fuel pump connector terminal 3.
Is the problem found?–Go to Step 6Go to Step 7
61. Repair the wire between the fuel pump relay
connector terminal 87 and the fuel pump con-
nector terminal 3.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
71. Replace the fuel pump relay.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
8Check for an open wire between the fuel pump relay
connector terminal 30 and the battery.
Is the problem found?–Go to Step 13–
9Check for an open wire between the fuel pump relay
connector terminal 85 to the engine control module
(ECM) connector terminal K54
Is the problem found.–Go to Step 10Go to Step 12
101. Repair the wire between the fuel pump relay
connector terminal 85 to the ECM connector
terminal K54.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–

ENGINE CONTROLS 1F – 71
DAEWOO V–121 BL4
MAIN RELAY CIRCUIT CHECK (1.4L/1.6L DOHC)
Circuit Description
When the ignition is turned On or to the START position,
the main relay is energized. The main relay then supply
voltage to the engine fuse block fuse Ef11. The Electronic
Ignition (EI) system ignition coil, Evaporative Emission
(EVAP) Canister Purge Solenoid and Heated Oxygen
Sensor (HO2S) are supplied voltage through the engine
fuse block fuse Ef11. The fuel injectors are supplied volt-
age through the engine fuse block fuse Ef11.Diagnostic Aids
S An intermittent problem may be caused by a poor
connection, rubbed through wire insulation, or a
broken wire inside the insulation.
S A fault main relay will cause a no start condition.
There will be no voltage supplied to the EI system
ignition coil, or the fuel injectors. Without voltage
supplied to these components, they will not oper-
ate.
Main Relay Circuit Check (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition OFF.
2. Disconnect the engine fuse block fuse Ef11.
3. Turn the ignition ON.
4. With a test light connected to the ground,
probe the fuse terminals nearest the main relay
for fuse Ef11.
Is the light on at both terminal?–System OKGo to Step 2
2Is the light on at only one terminal?–Go to Step 3Go to Step 4
3Repair the open in the wiring between the main relay
connector terminal 87 and the fuse Ef11.
Is the repair complete?–System OK–

ENGINE CONTROLS 1F – 73
DAEWOO V–121 BL4
MAIN RELAY CIRCUIT CHECK (1.8L DOHC)
Circuit Description
When the ignition is turned On or to the START position,
the main relay is energized. The main relay then supply
voltage to the engine fuse block fuse F2. The Electronic
Ignition (EI) system ignition coil, Evaporative Emission
(EVAP) Canister Purge Solenoid and Heated Oxygen
Sensor (HO2S) are supplied voltage through the engine
fuse block fuse F2. The fuel injectors are supplied voltage
through the engine fuse block fuse F2.Diagnostic Aids
S An intermittent problem may be caused by a poor
connection, rubbed through wire insulation, or a
broken wire inside the insulation.
S A fault main relay will cause a no start condition.
There will be no voltage supplied to the EI system
ignition coil, or the fuel injectors. Without voltage
supplied to these components, they will not oper-
ate.
Main Relay Circuit Check (1.8L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition OFF.
2. Disconnect the I/P fuse block fuse F2.
3. Turn the ignition ON.
4. With a test light connected to the ground,
probe the fuse terminals nearest the ignition
relay for fuse F2.
Is the light on at both terminal?–System OKGo to Step 2
2Is the light on at only one terminal?–Go to Step 3Go to Step 4
3Repair the open in the wiring between the ignition
relay connector terminal 87 and the fuse F2.
Is the repair complete?–System OK–

ENGINE CONTROLS 1F – 87
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
16Check the wire between the CKP sensor connector
terminal 1 and the ECM connector terminal 85 for an
open or short.
Is the problem found?Go to Step 18Go to Step 11
17Check the wire between the CKP sensor connector
terminal 3 and ground for an open or short.
Is the problem found?–Go to Step 19Go to Step 11
18Repair the wire between the CKP sensor connector
terminal 1 and the ECM connector terminal 85.
Is the repair complete?–System OK–
19Repair the wire between the CKP sensor connector
terminal 3 and ground.
Is the repair complete?–System OK–
201. Turn the ignition ON.
2. Measure the voltage between the CKP sensor
connector terminals 2 and 3.
Is the voltage within the value specified?1.3–1.5 v
(2.4–2.7 v)*Go to Step 24Go to Step 21
21Measure the voltage between the CKP sensor con-
nector terminal 2 and ground.
Is the voltage within the value specified?1.3–1.5 v
(2.4–2.7 v)*Go to Step 17Go to Step 22
22Check the wire between the CKP sensor connector
terminal 2 and the ECM connector terminal 54 for an
open or short.
Is the problem found?–Go to Step 23Go to Step 11
23Repair the wire between the CKP sensor connector
terminal 2 and the ECM connector terminal 54.
Is the repair complete?–System OK–
241. Turn the ignition OFF.
2. Connect a test light between the EI system
ignition coil connector terminal 2 and ground.
3. Turn the ignition ON.
Is the test light on?–Go to Step 25Go to Step 26
25Connect a test light between the EI system ignition
coil connector terminal 2 and battery positive.
Is the test light on?–Go to Step 5Go to Step 27
26Check for an open or short to ground in the wiring be-
tween the EI system ignition coil connector, terminal
2 and the ignition switch.
Is the problem found?–Go to Step 29–
27Repair the wire between the EI system ignition coil
connector terminal 1 and ground.
Is the repair complete?–System OK–
281. Turn the ignition OFF.
2. Replace the CKP sensor.
Is the repair complete?–System OK–
29Replace the fuse F2 or repair the open in the wiring
between the EI system ignition coil connector termi-
nal 2 and the ignition switch.
Is the repair complete?–System OK–