DAEWOO LACETTI 2004 Service Repair Manual

ENGINE CONTROLS 1F – 45
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
48Replace the fuse or repair the wiring as needed.
Is the repair complete?–Go to Step 2–
49Replace the ECM.
Is the repair complete?–Go to Step 2–

1F – 46IENGINE CONTROLS
DAEWOO V–121 BL4

ENGINE CONTROLS 1F – 47
DAEWOO V–121 BL4
ENGINE CRANKS BUT WILL NOT RUN (1.8L DOHC)
Test Description
The number(s) below refer to step(s) on the diagnostic
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. This
creates an electronic copy of the data taken when
the occurred. The information is then stored on the
scan tool for later reference.
2. By performing a compression test, it can be deter-
mined if the engine has the mechanical ability to
run.
3. It is important to check for the presence of sparkfrom all of the ignition wires. If spark is present from
one to three of the ignition coil terminals, the Crank-
shaft Position (CKP) sensor is OK.
19. In checking the engine control module (ECM) out-
puts for the electronic spark timing signal, it recom-
mended to use an oscilloscope to view the varying
voltage signals. In measuring these outputs with a
voltmeter, intermittent errors may occur that cannot
be seen by a voltmeter.
35. This step checks for proper operation of the ECM’s
control of the fuel pump circuit.
59. This step checks for a ground signal being supplied
by the ECM to operate the fuel injectors. If there is
no ground present during the cranking of the en-
gine, and the fuel injector wiring is OK, the ECM is
at fault.
Engine Cranks But Will Not Run (1.8L DOHC)
CAUTION : Use only electrically insulated pliers when
handling ignition wires with the engine running to
prevent an electrical shock.
CAUTION : Do not pinch or restrict nylon fuel lines.Damage to the lines could cause a fuel leak, resulting
in possible fire or personal injury.
Step
ActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic
(EOBD) Sys-
tem Check”
2Check for set Diagnostic Trouble Code (DTC)
P0601.
Is the DTC set?–Go to applica-
ble DTC tableGo to Step 4
3Crank the engine.
Does the engine start and continue to run?–System OKGo to Step 5
4Perform a cylinder compression test.
Is the cylinder compression for all of the cylinders at
or above the value specified?689 kPa
(100 psi)Go to Step 8Go to Step 5
5Inspect the timing belt alignment.
Is the timing belt in alignment?–Go to Step 7Go to Step 6
6Align or replace the timing belt as needed.
Is the repair complete?–Go to Step 3–
7Repair the internal engine damage as needed.
Is the repair complete?–Go to Step 3–
8Inspect the fuel pump fuse.
Is the problem found?–Go to Step 9Go to Step 10
9Replace the fuse.
Is the repair complete?–Go to Step 3–
101. Install a scan tool.
2. Turn the ignition ON, the engine OFF and close
the throttle.
Does the Throttle Position (TP) sensor read less
than the specified value.1.0 vGo to Step 11Go to ”DTC
P0123 Throttle
Position Sensor
High Voltage”

1F – 48IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
11Compare the Engine Coolant Temperature (ECT)
with the Intake Air Temperature (IAT).
Is the ECT relatively close to the IAT?–Go to Step 12Go to ”DTC
P0118 Engine
Coolant Tem-
perature High
Voltage
121. Check if the Manifold Absolute Pressure (MAP)
sensor reading is over the specified reading.
2. Crank the engine while watching the MAP sen-
sor reading.
Does the MAP sensor read above the specified val-
ue and then change while cranking the engine?4 vGo to Step 13Go to Step 14
13Crank the engine.
Does the Crankshaft Position (CKP) Active Counter
increment while cranking?–Go to Step 16Go to Step 18
14Check the scan data for serial data.
Was serial data lost while cranking the engine?–Go to Step 15Go to ”MAP
Sensor Output
Check”
15Repair voltage loss to the engine control module
(ECM) from the ignition switch.
Is the repair complete?–System OK–
16Check for the presence of spark from all of the igni-
tion wires while cranking the engine.
Is spark present from all of the ignition wires?–Go to Step 41Go to Step 17
171. Measure the resistance of the ignition wires.
2. Replace any of the ignition wire(s) with a resist-
ance above the value specified.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?30,000 WGo to Step 3Go to Step 18
181. Turn the ignition OFF.
2. Disconnect the Crankshaft Position (CKP) sen-
sor connector.
3. Measure the voltage between the CKP connec-
tor terminals 1 and 3.
4. Repair the wiring as needed.
Does the voltage measure near the value specified?1.4 v (2.5 v)*Go to Step 19Go to Step 20
19Measure the voltage between the CKP connector
terminals 2 and 3.
Does the voltage measure near the value specified1.4 v (2.5 v)*Go to Step 26Go to Step 21
20Measure the voltage between the CKP connector
terminals 1 and ground.
Does the voltage measure near the value specified?1.4 v (2.5 v)*Go to Step 22Go to Step 23
21Measure the voltage between the CKP connector
terminals 2 and ground.
Does the voltage measure near the value specified?1.4 v (2.5 v)*Go to Step 22Go to Step 24
22Check for an open or short in the wire between the
CKP connector terminal 3 and ground.
Is the problem found?–Go to Step 25Go to Step 40
23Check for an open or short in the wire between the
CKP connector terminal 1 and the ECM connector
terminal M21
Is the problem found?–Go to Step 25Go to Step 40

ENGINE CONTROLS 1F – 49
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
24Check for an open or short in the wire between the
CKP connector terminal 2 and the ECM connector
terminal M5.
Is the problem found?–Go to Step 25Go to 40
25Repair the wiring as needed.
Is the repair complete?–Go to Step 3–
261. Disconnect the Electronic Ignition (EI) system
ignition coil connector to prevent the vehicle
from starting.
2. Measure the voltage at the ECM connector
terminal M21 by backprobing the ECM connec-
tor.
Are the voltage readings near the values specified?1.4 v (2.5 v)*
with ignition
ON, 1.6 v (2.6
v)* during
crankingGo to Step 27Go to Step 28
27Measure the voltage at the ECM connector terminal
M5 by backprobing the ECM connector.
Are the voltage readings near the values specified?1.4 v (2.5 v)*
with ignition
ON, 1.6 v (2.6
v)* during
crankingGo to Step 29Go to Step 28
28Replace the CKP sensor.
Is the repair complete?–Go to Step 3–
291. Turn the ignition OFF.
2. Disconnect the electrical connector at the EI
system ignition coil.
3. Connect a test light between terminal 2 of the
EI system ignition coil connector and ground.
4. Turn the ignition ON.
Is the test light on?–Go to Step 30Go to Step 31
30Connect a test light of the EI system ignition coil con-
nector and battery positive.
Is the test light on?–Go to Step 34Go to Step 32
31Check for an open in the wiring between the ignition
switch and the EI system ignition coil connector ter-
minal 3.
Is the problem found?–Go to Step 33–
32Check for an open in the wire from the EI system
ignition coil to ground.
Is the problem found?–Go to Step 2–
331. Repair the wiring as needed.
2. Connect the EI system ignition coil connector.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?–Go to Step 3Go to Step 34
341. Turn the ignition OFF.
2. Disconnect the EI system ignition coil connec-
tor.
3. While cranking the engine, measure the volt-
age at the EI system ignition coil connector
terminal 1.
Does the voltage fluctuate within the values speci-
fied?0.2–2.0 vGo to Step 39Go to Step 37

1F – 50IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
35While cranking the engine, measure the voltage at
the EI system ignition coil connector terminal 3 .
Does the voltage fluctuate within the values speci-
fied?0.2–2.0 vGo to Step 39Go to Step 37
36Check for an open in the wire from the EI system
ignition coil connector terminal 1 to the ECM connec-
tor terminal M51.
Is the problem found?–Go to Step 38Go to Step 40
37Check for an open in the wire from the EI system
ignition coil connector terminal 3 to the ECM connec-
tor terminal M1.
Is the problem found?–Go to Step 38Go to Step 40
381. Repair the wiring as needed.
2. Connect the EI system ignition coil connector.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?–Go to Step 3Go to Step 39
39Replace the EI system ignition coil.
Is the repair complete?–Go to Step 3–
401. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 3–
411. Turn the ignition OFF.
2. Connect a fuel pressure gauge.
3. Crank the engine.
Is any fuel pressure present?–Go to Step 44Go to Step 42
421. Turn the ignition OFF.
2. Disconnect the electrical connector at the fuel
pump.
3. Connect a test light between the fuel pump
connector terminals 3 and 2.
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 43Go to Step 53
43Replace the fuel pump.
Is the repair complete?–Go to Step 3–
44Is the fuel pressure within the value specified?283–324 kPa
(41–47 psi)Go to Step 48Go to Step 45
451. Check the fuel filter for a restriction.
2. Inspect the fuel lines for kinks and restrictions.
Is the problem found?–Go to Step 46Go to Step 47
461. 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 present?283–324 kPa
(41–47 psi)Go to Step 3Go to Step 47

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 – 53
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
68Repair the open wire(s) between the fuel injector
harness connector(s) terminal 2 and the engine har-
ness C103 terminal 10.
Is the repair complete?–Go to Step 3–
691. Check for an open between the #1 fuel injector
harness connector terminal 1 and the connec-
tor terminal M25.
2. Check for an open between the #2 fuel injector
harness connector terminal 1 and the connec-
tor terminal M22.
3. Check for an open between the #3 fuel injector
harness connector terminal 1 and the connec-
tor terminal M24.
4. Check for an open between the #4 fuel injector
harness connector terminal 1 and the connec-
tor terminal M11.
Is the problem found?–Go to Step 70Go to Step 72
70Repair the open fuel injector harness wire(s).
Is the repair complete?–Go to Step 3–
71Replace the fuse or repair the wiring as needed.
Is the repair complete?–Go to Step 3–
721. Inspect the I/P fuse F2.
2. Check for an open between the circuits from
terminal 2 for each of the four fuel injectors and
the ignition switch.
Is the problem found?–Go to Step 71–

1F – 54IENGINE CONTROLS
DAEWOO V–121 BL4
NO MALFUNCTION INDICATOR LAMP (1.4L/1.6L 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 beinoperative.
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.