2004 DAEWOO LACETTI engine controls

ENGINE CONTROLS 1F – 439
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
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 applica-
ble DTC tableSystem OK

1F – 440IENGINE CONTROLS
DAEWOO V–121 BL4

ENGINE CONTROLS 1F – 441
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0304
CYLINDER 4 MISFIRE
System Description
The Engine Control Module (ECM) monitors the crank-
shaft and camshaft positions to detect if the engine is mis-
firing. The ECM looks for a quick drop in crankshaft speed.
This test is executed in blocks of 100 engine revolution
tests. It may take between one to several tests to store a
Diagnostic Trouble Code (DTC) and illuminate the Mal-
function Indicator Lamp (MIL). Under light misfire condi-
tions, it may also take more than one trip to set a DTC. Se-
vere misfire will flash the MIL, indicating that catalyst
damage is possible.
Conditions for Setting the DTC
S Emission threshold is 3%.
S 20 engine cycles have occurred since cranking has
started.
S A/C compressor clutch has not just engaged or dis-
engaged.
S Engine load and engine speed is in a detectable
region and is at or above zero torque.
S Camshaft Position (CMP) sensor is in synchroniza-
tion.
S Exhaust Gas Recirculation (EGR) flow diagnostic is
not in progress.
S Fuel level is greater than 12% of rated tank capac-
ity.
S Decel Fuel Cutoff (DFCO) not active.
S Throttle position change is less than 3% per 125
ms.
S Vehicle has not encountered an abusive engine
speed of 7000 rpm.
S Crankshaft speed patters are normal.
S Throttle position is less than 3% when vehicle
speed is greater than 10 km/h (6 mph).
S Vehicle voltage is between 11 and 16 volts.
S Engine Coolant Temperature (ECT) is between
–7°C (19°F) and 120°C (248°F).
S There is the correct ratio between Crankshaft Posi-
tion (CKP) sensor pulses and CMP sensor pulses.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0336, P0337, P0341, P0342 and
P0502 are not set.
Action Taken When the DTC Sets
S The MIL will illuminate after two consecutive ignition
cycles in which the diagnostic runs with the fault
active.
Or
S The MIL will illuminate immediately and flash if mis-
fire is present.
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
within the freeze frame conditions that the DTC
failed.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S The DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
An intermittent can also be the result of a defective reluctor
wheel. Remove the CKP sensor and inspect the reluctor
wheel through the sensor mount hole. Check for porosity
and the condition of wheel. If the DTC is intermittent refer
to”Symptoms Diagnosis” in this section.
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. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
3. A visual/physical inspection should include check-
ing the following components:
S The wiring for proper connections, pinches or
cuts.
S The ECM grounds for being clean and tight.
S The vacuum hoses for splits, kinks, and proper
connections as shown on the Vehicle Emission
Information label. Check thoroughly for any type
of leak or restriction.
S For air leaks at the throttle body mounting area
and intake manifold sealing surfaces.
5. When all the accumulators are relatively equal, then
the misfire is being caused by something that af-
fects the entire engine. When they are not then the
misfire is being caused by something that is specif-
ic to two or more cylinders.
6. Whenever the misfire is not present operating the
vehicle may be necessary to duplicate the condi-
tions in the Freeze Frame Data in order to detect
misfire. Depending on the engine load, the condi-
tions may have to be maintained for up to 20 sec-
onds. Whenever the misfire accumulators start to
increment, then misfire is present. A history misfire
counter will store the number of misfires that have
occurred until the DTC is cleared.

1F – 442IENGINE CONTROLS
DAEWOO V–121 BL4
8. Check the fuel for water, alcohol, etc.
9. A basic engine problem that affects all cylinders is
the only possibility at this point. (Cam timing,
throttle body leak, restricted air flow, etc.)
11. Tests the ignition system voltage output using a
spark tester.
12. Replace any spark plugs that are worn, cracked or
fouled.
13. Checks for voltage at the ignition feed circuit.
18. Whenever the driver circuit is shorted to ground,
the light will be on steady. When the driver circuit is
shorted to voltage or open, the light will be off.19. Since voltage is supplied to the fuel injector on a
single circuit, the malfunction could only be a poor
connection or open in the fuel injector harness. An
open before the harness would result in an ”Engine
Cranks But Will Not Run” complaint.
28. Before replacing the ECM, check terminals for im-
proper mating, broken locks, or physical damage to
the wiring harness. The replacement ECM must be
programmed. Refer to the latest Techline procedure
for ECM reprogramming.
DTC P0304 – Cylinder 4 Misfire
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON, with the engine OFF.
3. Request Diagnostic Trouble Codes (DTCs)
Are DTCs P0201 or P300 set?–Go to applica-
ble DTCGo to Step 3
31. Perform a visual/physical inspection.
2. Make any repairs that are necessary.
Is the repair complete?–Go to Step 27Go to Step 4
4Start the engine and allow it to idle.
Are any Misfire Current counters incrementing?–Go to Step 5Go to Step 6
5Are all counters equal (within a percentage of each
other)?–Go to Step 7Go to Step 11
61. 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 and conditions for setting this DTC
as noted.
Are any Misfire Current counters incrementing?–Go to Step 5Go to
”Diagnostic
Aids”
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–

ENGINE CONTROLS 1F – 443
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Turn the engine OFF.
2. Disconnect the fuel injector harness connector.
3. Install a spark tester on cylinder #4 spark plug
cable.
4. Crank the engine and check for spark.
Is a spark observed on all four spark plug cables?–Go to Step 12Go to Step 20
12Replace the malfunctioning spark plug.
Is the repair complete?–Go to Step 27Go to Step 13
131. Turn the engine OFF.
2. Disconnect the cylinder #4 fuel injector connec-
tors from the injector.
3. Install an injector test light on the injector har-
ness connector, terminal 1.
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.
3. Crank the engine.
Does the test light illuminate?–Go to Step 17Go to Step 19
16Replace the malfunctioning fuel injector.
Is the repair complete?–Go to Step 27 –
17Check the affected fuel injector driver circuit 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–
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.
Is the resistance of the spark plug cable less than the
specified value?30,000 WGo 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 needed.
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–

1F – 444IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
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 applica-
ble DTC tableSystem OK

ENGINE CONTROLS 1F – 445
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0317
ROUGH ROAD SENSOR SOURCE NOT DETECTED
System Description
The Engine Control Module (ECM) identifies engine mis-
fire by detecting variations in crankshaft speed. Crank-
shaft speed variations can also occur when a vehicle is op-
erating over a rough road. The ECM receives rough road
signal by gravity sensing rough road (G) sensor or Elec-
tronic Brake Control Module (EBCM) if equipped with the
Anti–Lock Brake System (ABS). The ABS can detect if the
vehicle is on the rough surface based on wheel accelera-
tion/deceleration data supplied by each wheel speed sen-
sor. This information sent to the ECM by EBCM through
serial data line. The G sensor is vertical low g–accelera-
tion sensor. By sensing vertical acceleration caused by
bumps or portholes in the road, the ECM determine if the
changes in crankshaft speed are due to engine misfire or
are driveline induced. If the ECM can not receive any of
those signal, a historic Diagnostic Trouble Code (DTC) will
be stored.
Conditions for Setting the DTCS ECM can not detect any rough road source.
S Vehicle speed is greater than 5km/h (3.1 mph).
Action Taken When the DTC Sets
S The MIL will not illuminate.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Failure Records buffers.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S The DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
An open signal circuit of G sensor or open serial data line
between the ECM and the EBCM will be the cause of this
DTC.

1F – 446IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0317 – Rough Road Sensor Source Not Detected
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON, with the engine OFF.
3. Request Diagnostic Trouble Codes (DTCs)
Are DTCs P1380, P1381, P1391, P1392 or P1393
set?–Go to
Applicable DTCGo to Step 3
3Is the vehicle equipped with the Anti–lock Brake
System (ABS)?–Go to Step 8Go to Step 4
41. Disconnect the gravity sensing rough road (G)
sensor connector.
2. Disconnect the Engine control Module (ECM)
connector.
3. Measure resistance between terminal B of the
G sensor and terminal K21 of the ECM.
Is the resistance within the specified value?0 ΩGo to Step 6Go to Step 5
5Repair open circuit.
Is the repair complete?–Go to Step 11Go to Step 6
61. Reconnect the ECM and G sensor connectors.
2. Turn the ignition ON.
3. Probe the voltage at terminal B of G sensor.
Is the voltage within the specified value?2.35–2.65 VGo to Step 10Go to Step 7
71. Turn the ignition OFF.
2. Replace the G sensor.
Is the repair complete?–Go to Step 11–
81. Turn the ignition OFF.
2. Disconnect the Electronic Brake Control Mod-
ule EBCM) connector and the ECM connector.
3. Measure the resistance between terminal 25 of
the EBCM and terminal K7 of the ECM.
Is the resistance within the specified value?0 ΩGo to Step 10Go to Step 9
9Repair open circuit.
Is the repair complete?–Go to Step 11Go to Step 10
101. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 11–
111. 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 12Go to Step 2
12Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK