GENERAL ENGINE INFORMATION 1A – 11
DAEWOO V–121 BL4
GENERAL INFORMATION
CLEANLINESS AND CARE
An automobile engine is a combination of many machined,
honed, polished and lapped surfaces with tolerances that
are measured in the ten–thousandths of an inch. When
any internal engine parts are serviced, care and cleanli-
ness are important. A liberal coating of engine oil should
be applied to friction areas during assembly, to protect and
lubricate the surfaces on initial operation. Proper cleaning
and protection of machined surfaces and friction areas is
part of the repair procedure. This is considered standard
shop practice even if not specifically stated.
Whenever valve train components are removed for ser-
vice, they should be kept in order. They should be installed
in the same locations, and with the same mating surfaces,
as when they were removed.Battery cables should be disconnected before any major
work is performed on the engine. Failure to disconnect
cables may result in damage to wire harness or other elec-
trical parts.ON–ENGINE SERVICE
CAUTION : Disconnect the negative battery cable be-
fore removing or installing any electrical unit, or
when a tool or equipment could easily come in con-
tact with exposed electrical terminals. Disconnecting
this cable will help prevent personal injury and dam-
age to the vehicle. The ignition must also be in LOCK
unless otherwise noted.
Notice : Any time the air cleaner is removed, the intake
opening should be covered. This will protect against acci-
dental entrance of foreign material, which could follow the
intake passage into the cylinder and cause extensive
damage when the engine is started.
ENGINE ELECTRICAL 1E – 9
DAEWOO V–121 BL4
STARTER MOTOR NOISE
To correct starter motor noise during starting, use the following procedure:
Checks
Action
Check for a high–pitched whine during cranking, before
the engine fires. The engine cranks and fires properly.The distance is too great between the starter pinion and
the flywheel. Shimming the starter toward the flywheel is
required.
Check for a high–pitched whine after the engine fires, as
the key is being released. The engine cranks and fires
properly. This intermittent complaint is often diagnosed as
”starter hang–in” or ”solenoid weak.”The distance is too small between the starter pinion and
the flywheel. Shimming the starter away from the flywheel
is required.
Check for a loud ”whoop” after the engine fires but while
the starter is still held engaged. The sound is like a siren
if the engine is revved while the starter is engaged.The most probable cause is a defective clutch. A new
clutch will often correct this problem.
Check for a ”rumble,” a ”growl,” or, in severe cases, a
”knock” as the starter is coasting down to a stop after start-
ing the engine.The most probable cause is a bent or unbalanced starter
armature. A new armature will often correct this problem.
If the complaint is noise, correction can be achieved by
proper shimming as follows:
1. Check for a bent or a worn flywheel.
2. Start the engine and carefully touch the outside di-
ameter of the rotating flywheel ring gear with chalk
or a crayon to show the high point of the tooth run-
out. Turn the engine OFF and rotate the flywheel so
that the marked teeth are in the area of the starter
pinion gear.
3. Disconnect the negative battery cable to prevent
cranking the engine.
4. Check the pinion–to–flywheel clearance by using a
wire gauge of 0.5 mm (0.02 inch) minimum thick-
ness (or diameter). Center a pinion tooth between
two flywheel teeth and the gauge. Do not gauge in
the corners, where a misleading larger dimension
may be observed. If the clearance is under this
minimum, shimming the starter away from the fly-
wheel is required.
5. If the clearance approaches 1.5 mm (0.06 inch) or
more, shimming the starter toward the flywheel is
required. This condition is generally the cause of
broken flywheel teeth or the starter housing. Shim
the starter toward the flywheel by shimming only
the outboard starter mounting pad. A shim of 0.40
mm (0.016 inch) thickness at this location will de-
crease the clearance by approximately 0.30 mm
(0.012 inch). If normal starter shims are not avail-
able, plain washers or other suitable material may
be used as shims.BATTERY LOAD TEST
1. Check the battery for obvious damage, such as a
cracked or broken case or cover, which could per-
mit the loss of electrolyte. If obvious damage is
noted, replace the battery.
CAUTION : Do not charge the battery if the hydrome-
ter is clear or light yellow. Instead, replace the battery.
If the battery feels hot, or if violent gassing or spew-
ing of electrolyte through the vent hole occurs, dis-
continue charging or reduce the charging rate to
avoid personal injury.
2. Check the hydrometer. If the green dot is visible, go
to the load test procedure. If the indicator is dark
but green is not visible, charge the battery. For
charging a battery removed from the vehicle, refer
to ”Charging a Completely Discharged Battery” in
this section.
3. Connect a voltmeter and a battery load tester
across the battery terminals.
4. Apply a 300–ampere load for 15 seconds to remove
any surface charge from the battery.
5. Remove the load.
6. Wait 15 seconds to let the battery recover, and ap-
ply a 270–ampere load.
Important : The battery temperature must be estimated
by touch and by the temperature condition the battery has
been exposed for the preceding few hours.
7. If the voltage does not drop below the minimum
listed, the battery is good and should be reinstalled.
If the voltage is less than the minimum listed, re-
place the battery. Refer to ”Battery Specifications”
in this section.
1F – 30IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSIS
SYSTEM DIAGNOSIS
DIAGNOSTIC AIDS
If an intermittent problem is evident, follow the guidelines
below.
Preliminary Checks
Before using this section you should have already per-
formed the ”On–Board Diagnostic System Check.”
Perform a thorough visual inspection. This inspection can
often lead to correcting a problem without further checks
and can save valuable time. Inspect for the following con-
ditions:
S Engine control module (ECM) grounds for being
clean, tight, and in their proper location.
S Vacuum hoses for splits, kinks, collapsing and prop-
er connections as shown on the Vehicle Emission
Control Information label. Inspect thoroughly for
any type of leak or restriction.
S Air leaks at the throttle body mounting area and the
intake manifold sealing surfaces.
S Ignition wires for cracks, hardness, proper routing,
and carbon tracking.
S Wiring for proper connections.
S Wiring for pinches or cuts.
Diagnostic Trouble Code Tables
Do not use the Diagnostic Trouble Code (DTC) tables to
try to correct an intermittent fault. The fault must be pres-
ent to locate the problem.
Incorrect use of the DTC tables may result in the unneces-
sary replacement of parts.
Faulty Electrical Connections or Wiring
Most intermittent problems are caused by faulty electrical
connections or wiring. Perform a careful inspection of sus-
pect circuits for the following:
S Poor mating of the connector halves.
S Terminals not fully seated in the connector body.
S Improperly formed or damaged terminals. All con-
nector terminals in a problem circuit should be care-
fully inspected, reformed, or replaced to insure con-
tact tension.S Poor terminal–to–wire connection. This requires
removing the terminal from the connector body.
Road Test
If a visual inspection does not find the cause of the prob-
lem, the vehicle can be driven with a voltmeter or a scan
tool connected to a suspected circuit. An abnormal voltage
or scan tool reading will indicate that the problem is in that
circuit.
If there are no wiring or connector problems found and a
DTC was stored for a circuit having a sensor, except for
DTC P0171 and DTC P0172, replace the sensor.
Fuel System
Some intermittent driveability problems can be attributed
to poor fuel quality. If a vehicle is occasionally running
rough, stalling, or otherwise performing badly, ask the cus-
tomer about the following fuel buying habits:
S Do they always buy from the same source? If so,
fuel quality problems can usually be discounted.
S Do they buy their fuel from whichever fuel station
that is advertising the lowest price? If so, check the
fuel tank for signs of debris, water, or other contam-
ination.
IDLE LEARN PROCEDURE
Whenever the battery cables, the engine control module
(ECM), or the ECM fuse is disconnected or replaced, the
following idle learn procedure must be performed:
1. Turn the ignition ON for 5 seconds.
2. Turn the ignition OFF for 5 seconds.
3. Turn the ignition ON for 5 seconds.
4. Start the engine in park/neutral.
5. Allow the engine to run until the engine coolant is
above 185° F (85°C ).
6. Turn the A/C ON for 10 seconds, if equipped.
7. Turn the A/C OFF for 10 seconds, if equipped.
8. If the vehicle is equipped with an automatic trans-
axle, apply the parking brake. While pressing the
brake pedal, place the transaxle in D (drive).
9. Turn the A/C ON for 10 seconds, if equipped.
10. Turn the A/C OFF for 10 seconds, if equipped.
11. Turn the ignition OFF. The idle learn procedure is
complete.
ENGINE CONTROLS 1F – 117
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0108
MANIFOLD ABSOLUTE PRESSURE SENSOR HIGH
VOLTAGE
Circuit Description
The engine control module (ECM) uses the Manifold Ab-
solute Pressure (MAP) sensor to control the fuel delivery
and the ignition timing. The MAP sensor measures the
changes in the intake manifold pressure, which results
from engine load (intake manifold vacuum) and the rpm
changes; and converts these into voltage outputs. The
ECM sends a 5 volt–reference voltage to the MAP sensor.
As the manifold pressure changes, the output voltage of
the MAP sensor also changes. By monitoring the MAP
sensor output voltage, the ECM knows the manifold pres-
sure. A low–pressure (low voltage) output voltage will be
about 1.0 to 1.5 volts at idle, while higher pressure (high
voltage) output voltage will be about 4.5 to 4.8 at wide
open throttle (WOT). The MAP sensor is metric pressure,
allowing the ECM to make adjustments for different alti-
tudes.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S When the engine idling.
S Engine speed is greater than 700rpm.
S No throttle position sensor (TPS) fail conditions
present.
S The MAP is greater than 95kPA.
S A high voltage 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.
S The ECM will substitutes a fixed MAP value and
use TP to control the fuel delivery (the scan tool will
not show defaulted)
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
With the ignition ON and the engine stopped, the manifold
pressure is equal to atmosphere pressure and the signal
voltage will be high.
The ECM as an indication of vehicle altitude uses this in-
formation. Comparison of this reading with a known good
vehicle with the same sensor is a good way to check the
accuracy of a suspect sensor. Readings should be the
same ±0.4volt.
If a DTC P0108 is intermittent, refer to ”Manifold Absolute
Pressure Check” in this section for further diagnosis.
If the connections are OK monitor the manifold absolute
pressure(MAP) sensor signal voltage while moving re-
lated connectors and the wiring harness. If the failure is in-
duced, the display on the scan tool will change. This may
help to isolate the location of an intermittent malfunction.
1F – 158IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0171
FUEL TRIM SYSTEM TOO LEAN
System Description
If the adaptation value threshold is permanently exceed-
ed, the deviation of the adaptive terms enables to detect
a slow default coming out. Two time counters (one for the
rich side and another one for the lean side) are increased
while the lambda controller exceeds the adaptation
thresholds. As soon as one of the time counters reaches
its maximum value, the error is detected.
The aim of this test is to simulate a failure that would result
in exceeding the adaptive terms. Two kinds of failure must
be created.
S A lean side deviation: P0171
S A rich side deviation : P0172
It is thus necessary to determine, for each kind of failure,
the limit good and the limit bad. For a given failure, mea-
sure the emission threshold until the legal emission
thresholds are exceeded.
Note that the problem is due to the emission thresholds re-
quired, it is not simple to disturb the system so that the
emission thresholds will be exceeded. The tuning has
been made thanks to a dedicated calibration but, as such
a procedure is not permitted by the regulation, it is neces-
sary to create some material malfunction (fuel pressure
regulator, fuel injector, air leakage...).
Conditions for Setting the DTC
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0132, P0337,
P0338, P0341, P0342, P0400, P1319, P1402,
P1404, P1405, P1671 and P1672 are not set.
S Coolant temperature is greater than 20°C (68°F).
(1.4L DOHC)
S Coolant temperature is greater than 80°C (176°F).
(1.6L DOHC)
S Manifold Absolute Pressure (MAP) is greater than
70 kPa (10.2 psi).
S System is in closed loop.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. 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 10 sec-
onds.
Diagnostic Aids
Important : After repairs, use the scan tool Fuel Trim Re-
set function to reset the long–term fuel trim to 128 (0%).
S Fuel pressure – The system will be lean if the pres-
sure is too low. It may be necessary to monitor fuel
pressure while driving the vehicle at various road
speeds and/or loads to confirm.
S Map sensor – An output that causes the ECM to
sense a lower than normal manifold pressure (high
vacuum) can cause the system to go lean. Discon-
necting the MAP sensor will allow the ECM to sub-
stitute a fixed (default) value for the MAP sensor. If
the lean condition is gone when the sensor is dis-
connected, substitute a known good sensor and
recheck.
S Fuel contamination – Water, in even small amounts,
near the in–tank fuel pump inlet can be delivered to
the injector. The water causes a lean exhaust and
can set DTC P0171.
Check for poor O2S or MAP sensor connection at the
ECM. Inspect the harness connectors 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
Inspect the wiring harness for damage. If the harness ap-
pears to be OK, observe the O2S display on the scan tool
while moving the connectors and the wiring harness re-
lated to the engine harness. A change in the display will
indicate the location of the fault.
Check the brake power booster check valve for possible
leaks.
1F – 162IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0172
FUEL TRIM SYSTEM TOO RICH
System Description
If the adaptation value threshold is permanently exceed-
ed, the deviation of the adaptive terms enables to detect
a slow default coming out. Two time counters (one for the
rich side and another one for the lean side) are increased
while the lambda controller exceeds the adaptation
thresholds. As soon as one of the time counters reaches
its maximum value, the error is detected.The aim of this
test is to simulate a failure that would result in exceeding
the adaptive terms. Two kinds of failure must be created.
S A lean side deviation: P0171
S A rich side deviation : P0172
It is thus necessary to determine, for each kind of failure,
the limit good and the limit bad. For a given failure, mea-
sure the emission threshold until the legal emission
thresholds are exceeded.Note that the problem is due to
the emission thresholds required, it is not simple to disturb
the system so that the emission thresholds will be exceed-
ed. The tuning has been made thanks to a dedicated cal-
ibration but, as such a procedure is not permitted by the
regulation, it is necessary to create some material mal-
function (fuel pressure regulator, fuel injector, air leak-
age...).
Conditions for Setting the DTC
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0132, P0337,
P0338, P0341, P0342, P0400, P1319, P1402,
P1404, P1405, P1671 and P1672 are not set.
S Coolant temperature is greater than 20°C (68°F).
(1.4L DOHC)
S Coolant temperature is greater than 80°C (176°F).
(1.6L DOHC)
S Manifold Absolute Pressure (MAP) is greater than
70 kPa (10.2 psi).
S System is in closed loop.
Action Taken When the DTC SetsS The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. 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 10 sec-
onds.
Diagnostic Aids
Important : After repairs, use the scan tool Fuel Trim Re-
set function to reset the long–term fuel trim to 128 (0%).
Check for poor connection at the ECM. Inspect the har-
ness connectors 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.
Inspect the wiring harness for damage. If the harness ap-
pears to be OK, observe the O2S display on the scan tool
while moving the connectors and the wiring harness re-
lated to the engine harness. A change in the display will
indicate the location of the fault.
If a DTC P1404 is also set, check the 5 volt reference cir-
cuits for a short to voltage.
Check for a restricted exhaust system.
A shorted 5 volt reference circuit may cause a DTC P0172
to set. Check the 5 volt reference sensors for abnormal
readings.
DTC P0172 – Fuel Trim System Too Rich
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install the scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Are any component related Diagnostic Trouble
Codes (DTCs) set?–Go to
applicable DTC
tableGo to Step 3
ENGINE CONTROLS 1F – 201
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0335
MAGNETIC CRANKSHAFT POSITION SENSOR
ELECTRICAL ERROR
Circuit Description
The 58X reference signal is produced by the crankshaft
position (CKP) sensor. During one crankshaft revolution,
58 crankshaft pulses will be produced. The transaxle con-
trol module(TCM)/engine control module(ECM) uses the
58X reference signal to calculate engine rpm and CKP.
The ECM constantly monitors the number of pulses on the
58X reference circuit and compares them to the number
of camshaft position (CKP) signal pulses being received.
If the ECM receive and incorrect number of pulses on the
58X reference circuit, DTC P0335 will set.
Conditions for Setting the DTC
S The magnetic crankshaft position sensor is greater
than 0.2V.
Or
S The minimum value of magnetic crankshaft position
sensor is less than 1.5V.
Or
S The maximum value of magnetic crankshaft posi-
tion sensor is higher than 2.2V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. 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
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside the
insulation. Check for :
Poor connection – inspect the ECM harness and connec-
tors for improper mating, broken locks, improperly formed
or damaged terminals, and poor terminal–to–wire connec-
tion.
Damaged harness – inspect the wiring harness for dam-
age. If the harness appears to be OK, disconnect the
ECM, turn the ignition ON and observe a voltmeter con-
nected to the 58X reference circuit at the ECM harness
connector while moving the connectors and the wiring har-
ness related to the ECM. A change in voltage will indicate
the location of the fault.
Review the failure records vehicle mileage since the diag-
nostic test failed may help determine how often the condi-
tion that caused the DTC to be set occurs. This may assist
in diagnosing the condition.
1F – 204IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0336
58X CRANKSHAFT POSITION SENSOR NO PLAUSIBLE
SIGNAL
Circuit Description
The 58X reference signal is produced by the crankshaft
position (CKP) sensor. During one crankshaft revolution,
58 crankshaft pulses will be produced. The transaxle con-
trol module(TCM)/engine control module(ECM) uses the
58X reference signal to calculate engine rpm and CKP.
The ECM constantly monitors the number of pulses on the
58X reference circuit and compares them to the number
of camshaft position (CKP) signal pulses being received.
If the ECM receive and incorrect number of pulses on the
58X reference circuit, DTC P0336 will set.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S Detected number of teeth is differs by 3 or higher.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
Conditions for Clearing the MIL/DTCS 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
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside the
insulation. Check for :
Poor connection – inspect the ECM harness and connec-
tors for improper mating, broken locks, improperly formed
or damaged terminals, and poor terminal–to–wire connec-
tion.
Damaged harness – inspect the wiring harness for dam-
age. If the harness appears to be OK, disconnect the
ECM, turn the ignition ON and observe a voltmeter con-
nected to the 58X reference circuit at the ECM harness
connector while moving the connectors and the wiring har-
ness related to the ECM. A change in voltage will indicate
the location of the fault.
Review the failure records vehicle mileage since the diag-
nostic test failed may help determine how often the condi-
tion that caused the DTC to be set occurs. This may assist
in diagnosing the condition.