2004 DAEWOO NUBIRA spark plug

ENGINE CONTROLS 1F – 85
DAEWOO V–121 BL4
IGNITION SYSTEM CHECK (1.4L/1.6L DOHC)
Circuit Description
The Electronic Ignition (EI) system uses a waste spark
method of spark distribution. In this type of EI system, the
Crankshaft Position (CKP) sensor is mounted to the oil
pump near a slotted wheel that is a part of the crankshaft
pulley. The CKP sensor sends reference pulses to the en-
gine control module (ECM). The ECM then triggers the EI
system ignition coil. Once the ECM triggers the EI system
ignition coil, both of the connected spark plugs fire at the
same time. One cylinder is on its compression stroke at
the same time that the other is on the exhaust stroke, re-
sulting in lower energy needed to fire the spark plug in the
cylinder on its exhaust stroke.
This leaves the remainder of the high voltage to be used
to fire the spark plug in the cylinder on its compression
stroke. Since the CKP sensor is in a fixed position, timing
adjustments are not possible or needed.
Test Description
The number(s) below refer to step(s) on the diagnostictable.
2. It is important to check for the presence of spark to
all of the cylinders to isolate the problem to either
EI system ignition coil inputs or outputs.
5. In checking the ECM outputs for the electronic
spark timing signal, it recommended to use an os-
cilloscope to view the varying voltage signals. In
measuring these outputs with a voltmeter, intermit-
tent errors may occur that cannot be seen by a volt-
meter.
6. After confirming ECM inputs for the electronic spark
timing to the EI system ignition coil are OK, it can
be determined that a faulty EI system ignition coil is
at fault.
11. After confirming proper CKP sensor inputs to the
ECM and no wiring problems present, it can be de-
termined that the ECM is at fault.
24. This step, along with step 25, checks for battery
voltage and a ground to the EI system ignition coil.
Ignition System Check (1.4L/1.6L DOHC)
CAUTION : Use only electrically insulated pliers when handling ignition wires with the engine running to prevent
an electrical shock.
Step
ActionValue(s)YesNo
11. Remove the spark plugs.
2. Inspect for wet spark plugs, cracks, wear, im-
proper gap, burned electrodes, or heavy de-
posits.
3. Replace the spark plugs as needed.
Is the repair complete?–System OKGo to Step 2
2Check 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?–System OKGo to Step 3
31. Measure the resistance of the ignition wires.
2. Replace any ignition wire(s) with a resistance
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 WSystem OKGo to Step 4
4Is spark present from at least one of the ignition
wires, but not all of the ignition wires?–Go to Step 5Go to Step 12
51. Turn the ignition OFF.
2. Disconnect the Electronic Ignition (EI) system
ignition coil connector.
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 6Go to Step 7

1F – 88IENGINE CONTROLS
DAEWOO V–121 BL4
IGNITION SYSTEM CHECK (1.8L DOHC)
Circuit Description
The Electronic Ignition (EI) system uses a waste spark
method of spark distribution. In this type of EI system, the
Crankshaft Position (CKP) sensor is mounted to the oil
pump near a slotted wheel that is a part of the crankshaft
pulley. The CKP sensor sends reference pulses to the en-
gine control module (ECM). The ECM then triggers the EI
system ignition coil. Once the ECM triggers the EI system
ignition coil, both of the connected spark plugs fire at the
same time. One cylinder is on its compression stroke at
the same time that the other is on the exhaust stroke, re-
sulting in lower energy needed to fire the spark plug in the
cylinder on its exhaust stroke.
This leaves the remainder of the high voltage to be used
to fire the spark plug in the cylinder on its compression
stroke. Since the CKP sensor is in a fixed position, timing
adjustments are not possible or needed.
Test Description
The number(s) below refer to step(s) on the diagnostictable.
2. It is important to check for the presence of spark to
all of the cylinders to isolate the problem to either
EI system ignition coil inputs or outputs.
5. In checking the ECM outputs for the electronic
spark timing signal, it recommended to use an os-
cilloscope to view the varying voltage signals. In
measuring these outputs with a voltmeter, intermit-
tent errors may occur that cannot be seen by a volt-
meter.
6. After confirming ECM inputs for the electronic spark
timing to the EI system ignition coil are OK, it can
be determined that a faulty EI system ignition coil is
at fault.
11. After confirming proper CKP sensor inputs to the
ECM and no wiring problems present, it can be de-
termined that the ECM is at fault.
24. This step, along with step 25, checks for battery
voltage and a ground to the EI system ignition coil.

ENGINE CONTROLS 1F – 89
DAEWOO V–121 BL4
Ignition System Check (1.8L DOHC)
CAUTION : Use only electrically insulated pliers when handling ignition wires with the engine running to prevent
an electrical shock.
Step
ActionValue(s)YesNo
11. Remove the spark plugs.
2. Inspect for wet spark plugs, cracks, wear, im-
proper gap, burned electrodes, or heavy de-
posits.
3. Replace the spark plugs as needed.
Is the repair complete?–System OKGo to Step 2
2Check 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?–System OKGo to Step 3
31. Measure the resistance of the ignition wires.
2. Replace any ignition wire(s) with a resistance
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 WSystem OKGo to Step 4
4Is spark present from at least one of the ignition
wires, but not all of the ignition wires?–Go to Step 5Go to Step 12
51. Turn the ignition OFF.
2. Disconnect the Electronic Ignition (EI) system
ignition coil connector.
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 6Go to Step 7
6While 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 10Go to Step 8
7Check for an open in the wire from the EI system
ignition coil connector terminal 1 to the engine con-
trol module (ECM) connector terminal M35 or M51.
Is the problem found?–Go to Step 9Go to Step 11
8Check for an open in the wire from the EI system
ignition coil connector terminal 3 to the ECM connec-
tor terminal M1 or M33.
Is the problem found?–Go to Step 9Go to Step 11
91. 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?–System OK–

ENGINE CONTROLS 1F – 189
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Turn the engine OFF.
2. Install a fuel pressure gauge to the fuel rail.
3. Observe the fuel pressure with the engine run-
ning.
Is the fuel pressure within the specified value?284–325 kPa
(41–47 psi)Go to Step 8Go to
”Fuel System
Diagnosis”
8Check the fuel for contamination.
Is the fuel OK?–Go to Step 9Go to Step 10
9Check for a basic engine problem and repair as nec-
essary.
Is the repair complete?–Go to Step 27–
10Replace the contaminated fuel.
Is the repair complete?–Go to Step 27–
111. Turn the engine OFF.
2. Disconnect the fuel injector harness connector.
3. Install a spark tester on cylinder #1 spark plug
cable.
4. Crank the engine and check for spark.
5. Repeat the above procedure on cylinders #2,
#3 and #4.
Is a spark observed on all four spark plug cables?–Go to Step 12Go to Step 20
12Replace any malfunctioning spark plugs if neces-
sary.
Is the repair complete?–Go to Step 27Go to Step 13
131. Turn the engine OFF.
2. Disconnect the fuel injector connectors from
the injectors.
3. Install an injector test light on the injector har-
ness connector for the cylinders that had mis-
fired.
4. Crank the engine and note the test light.
Does the injector test light blink?–Go to Step 14Go to Step 15
14Perform the Fuel Injector Balance Test.
Are the fuel injectors OK?–Go to Step 9Go to Step 16
151. Disconnect the injector test light.
2. With a test light connected to ground, probe
the ignition feed terminal 2 of the injector har-
ness connector for each cylinder that had mis-
fire.
3. Crank the engine.
Does the test light illuminate?–Go to Step 17Go to Step 19
16Replace any malfunctioning fuel injectors.
Is the repair complete?Go to Step 27–
17Check the affected fuel injector driver circuit at termi-
nals 59, 89, 90, and 60 for an open, short, or short
to voltage.
Is a problem found?–Go to Step 18Go to Step 24
18Repair the open or the shorted fuel injector driver cir-
cuit.
Is the repair complete?–Go to Step 27–

1F – 190IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
19Repair the open ignition feed circuit between the fuel
injector harness connector and the fuel injector con-
nector.
Is the repair complete?–Go to Step 27–
20Measure the resistance of the spark plug cable that
the spark plug tester did not spark.
Is the resistance of the spark plug cable less than the
specified value?30000WGo to Step 21Go to Step 25
21Inspect the Engine Control Module (ECM) connec-
tor and connections.
Are the connections OK?–Go to Step 22Go to Step 23
22Check the affected cylinders ignition control circuit
for an open or short and repair as necessary.
Is the repair complete?–Go to Step 27Go to Step 26
23Repair the connector or connections.
Is the repair complete?–Go to Step 27–
241. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 27–
25Replace the spark plug cable.
Is the repair complete?–Go to Step 27–
26Replace the faulty ignition coil.
Is the repair complete?–Go to Step 27Go to Step 24
271. 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 supported in the text.
Does the scan tool indicate that this diagnostic ran
and passed?–Go to Step 28Go to Step 2
28Check 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 – 193
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Turn the engine OFF.
2. Install a fuel pressure gauge to the fuel rail.
3. Observe the fuel pressure with the engine run-
ning.
Is the fuel pressure within the specified value?284–325 kPa
(41–47 psi)Go to Step 8Go to
”Fuel System
Diagnosis”
8Check the fuel for contamination.
Is the fuel OK?–Go to Step 9Go to Step 10
9Check for a basic engine problem and repair as nec-
essary.
Is the repair complete?–Go to Step 27–
10Replace the contaminated fuel.
Is the repair complete?–Go to Step 27–
111. Turn the engine OFF.
2. Disconnect the fuel injector harness connector.
3. Install a spark tester on cylinder #1 spark plug
cable.
4. Crank the engine and check for spark.
5. Repeat the above procedure on cylinders #2,
#3 and #4.
Is a spark observed on all four spark plug cables?–Go to Step 12Go to Step 20
12Replace any malfunctioning spark plugs if neces-
sary.
Is the repair complete?–Go to Step 27Go to Step 13
131. Turn the engine OFF.
2. Disconnect the fuel injector connectors from
the injectors.
3. Install an injector test light on the injector har-
ness connector for the cylinders that had mis-
fired.
4. Crank the engine and note the test light.
Does the injector test light blink?–Go to Step 14Go to Step 15
14Perform the Fuel Injector Balance Test.
Are the fuel injectors OK?–Go to Step 9Go to Step 16
151. Disconnect the injector test light.
2. With a test light connected to ground, probe
the ignition feed terminal 2 of the injector har-
ness connector for each cylinder that had mis-
fire.
3. Crank the engine.
Does the test light illuminate?–Go to Step 17Go to Step 19
16Replace any malfunctioning fuel injectors.
Is the repair complete?Go to Step 27–
17Check the affected fuel injector driver circuit at termi-
nals 59, 89, 90, and 60 for an open, short, or short
to voltage.
Is a problem found?–Go to Step 18Go to Step 24
18Repair the open or the shorted fuel injector driver cir-
cuit.
Is the repair complete?–Go to Step 27–

1F – 194IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
19Repair the open ignition feed circuit between the fuel
injector harness connector and the fuel injector con-
nector.
Is the repair complete?–Go to Step 27–
20Measure the resistance of the spark plug cable that
the spark plug tester did not spark.
Is the resistance of the spark plug cable less than the
specified value?30000WGo to Step 21Go to Step 25
21Inspect the Engine Control Module (ECM) connec-
tor and connections.
Are the connections OK?–Go to Step 22Go to Step 23
22Check the affected cylinders ignition control circuit
for an open or short and repair as necessary.
Is the repair complete?–Go to Step 27Go to Step 26
23Repair the connector or connections.
Is the repair complete?–Go to Step 27–
241. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 27–
25Replace the spark plug cable.
Is the repair complete?–Go to Step 27–
26Replace the faulty ignition coil.
Is the repair complete?–Go to Step 27Go to Step 24
271. 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 supported in the text.
Does the scan tool indicate that this diagnostic ran
and passed?–Go to Step 28Go to Step 2
28Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 214IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0351
IGNITION SIGNAL COIL A FAULT
Circuit Description
The engine control module (ECM) provides a ground for
the electronic spark timing 1 circuit. When the ECM re-
moves the ground path of the ignition primary coil, the
magnetic field produced by the coil collapses. The collaps-
ing magnetic field produces a voltage in the secondary coil
which fires the spark plug. The circuit between the ECM
and the electronic ignition system is monitored for an open
circuit, short to voltage, and low voltage. When the ECM
detects a problem in the spark timing 1 circuit, it will set
DTC P0351.
Conditions for Setting the DTC
S The ignition signal coil A circuit is an open or a
short to ground or short to battery 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 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.
Diagnostic Aids
Check and correct any abnormal engine noise before us-
ing the diagnostic table.
Any circuitry that is suspected as causing engine noise
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 terminal–to–wire connection
S Physical damage to the wiring harness