GENERAL ENGINE INFORMATION 1A–9
DAEWOO M-150 BL2
GENERAL DIAGNOSIS (Cont’d)
Condition Probable cause Correction
Poor FuelMalfunction ofImproper ignition timing.Adjust the ignition timing.
ConsumptionIgnition SystemAbnormal spark plug
(Excessive carbon deposit,
inadequate gap, burnt
electrode).Replace the plug.
Electric leakage or poor
connection of the high
tension cable.Connect the cable normally
or replace it.
Malfunction of
Cooling SystemMalfunction of the
thermostat.Replace the thermostat.
OthersImproperly installed valve.Repair or replace the valve.
Slipping clutch.Repair or replace the clutch.
Low pressure of tires.Adjust the pressure of tires.
ExcessiveLeakage ofLoosened oil drain plug.Tighten the plug.
Consumption of
Engine OilEngine OilLoosened oil pan bolt.Tighten the bolt.Engine Oil
Loosened oil filter.Tighten the filter.
Loosened oil pressure
switch.Tighten the switch.
Leakage of camshaft front oil
seal.Replace the seal.
Leakage of crankshaft front
oil seal.Replace the seal.
Leakage at the cylinder head
cover gasket.Replace the gasket.
Damage of the cylinder head
gasket.Replace the gasket.
Oil Mixing in
CombustionStuck piston ring.Remove carbon and replace
the ring.
ChamberWorn piston or cylinder.Replace the piston or the
cylinder.
Worn piston ring or ring
groove.Replace the piston or ring.
Inadequate position of the
piston ring cutting part.Adjust the position.
Abrasion or damage of the
valve system.Replace the valve system.
Low Oil PressureMalfunction of
LubricationInadequate oil viscosity.Replace with the specified
one.
SystemLoosening of the oil pressure
switch.Tighten the switch.
Lack of engine oil.Refill oil.
Blocking oil strainer.Clean the strainer.
ENGINE CONTROLS 1F–9
DAEWOO M-150 BL2
appropriate wiring diagram. Refer to “ECM Wiring Dia-
grams” in this Section.
9591
Terminal 49GroundOpen
STRATEGY-BASED DIAGNOSTICS
Strategy-Based Diagnostics
The strategy-based diagnostic is a uniform approach to
repair all Electrical/Electronic (E/E) systems. The diag-
nostic flow can always be used to resolve an E/E system
problem and is a starting point when repairs are neces-
sary. The following steps will instruct the technician on
how to proceed with a diagnosis:
Verify the customer complaint. To verify the customer
complaint, the technician should know the normal op-
eration of the system.
Perform preliminary checks as follows:
Conduct a thorough visual inspection.
Review the service history.
Detect unusual sounds or odors.
Gather Diagnostic Trouble Code (DTC) information to
achieve an effective repair.
Check bulletins and other service information. This
includes videos, newsletters, etc.
Refer to service information (manual) system
check(s).
Refer to service diagnostics.
No Trouble Found
This condition exists when the vehicle is found to oper-
ate normally. The condition described by the customer
may be normal. Verify the customer complaint against
another vehicle that is operating normally. The condition
may be intermittent. Verify the complaint under the con-
ditions described by the customer before releasing the
vehicle.
Re-examine the complaints.
When the complaints cannot be successfully found or
isolated, a re-evaluation is necessary. The complaint
should be re-verified and could be intermittent as de-
fined in “intermittents,” or could be normal.
After isolating the cause, the repairs should be made.
Validate for proper operation and verify that the symp-
tom has been corrected. This may involve road testing
or other methods to verify that the complaint has re-
solved under following conditions:
Conditions noted by the customer.
If a DTC was diagnosed, verify the repair be duplicat-
ing conditions present when the DTC was set as
noted in Failure Records or Freeze Frame data.
Verifying Vehicle Repair
Verification of the vehicle repair will be more compre-
hensive for vehicles with Euro On-Board Diagnostic
(EOBD) system diagnostics. Following a repair, the
technician should perform the following steps:
Important: Follow the steps below when you verify re-
pairs on EOBD systems. Failure to follow these steps
could result in unnecessary repairs.
Review and record the Failure Records and the
Freeze Frame data for the DTC which has been diag-
nosed (Freeze Fame data will only be stored for an A,
B and E type diagnostic and only if the Malfunction
Indicator Lamp has been requested).
Clear the DTC(s).
Operate the vehicle within conditions noted in the
Failure Records and Freeze Frame data.
Monitor the DTC status information for the specific
DTC which has been diagnosed until the diagnostic
test associated with that DTC runs.
EOBD SERVICEABILITY ISSUES
Based on the knowledge gained from Euro On-Board
Diagnostic (OBD) experience in the 1994 and 1995
model years in United Status, this list of non-vehicle
faults that could affect the performance of the Euro On-
Board Diagnostic (EOBD) system has been compiled.
These non-vehicle faults vary from environmental condi-
tions to the quality of fuel used. With the introduction of
EOBD across the entire passenger car, illumination of
the Malfunction Indicator Lamp (MIL) due to a non-ve-
hicle fault could lead to misdiagnosis of the vehicle, in-
creased warranty expense and customer
dissatisfaction. The following list of non-vehicle faults
does not include every possible fault and may not apply
equally to all product lines.
Fuel Quality
Fuel quality is not a new issue for the automotive indus-
try, but its potential for turning on the MIL with EOBD
systems is new.
Fuel additives such as “dry gas” and “octane enhancers”
may affect the performance of the fuel. If this results in
an incomplete combustion or a partial burn, it will set
Diagnostic Trouble Code (DTC) P0300. The Reed Vapor
Pressure of the fuel can also create problems in the fuel
system, especially during the spring and fall months
when severe ambient temperature swings occur. A high
Reed Vapor Pressure could show up as a Fuel Trim
DTC due to excessive canister loading.
Using fuel with the wrong octane rating for your vehicle
may cause driveability problems. Many of the major fuel
companies advertise that using “premium” gasoline will
improve the performance of your vehicle. Most premium
1F–210 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F240
DIAGNOSTIC TROUBLE CODE (DTC) – P0444 EVAP PURGE CONTROL
CIRCUIT NO SIGNAL
Circuit Description
The evaporative emission (EVAP) system includes the
following components :
Fuel tank.
EVAP vent solenoid.
Fuel pipes and hoses.
Fuel vapor lines.
Fuel cap.
EVAP canister.
Purge lines.
EVAP canister purge valve.
EVAP service port.
The evaporative emission system is checked by apply-
ing vacuum to the EVAP system and monitoring for a
vacuum decay. The engine control module(ECM) moni-
tors the vacuum level through the fuel tank pressure
sensor signal. At the appropriate time, the EVAP canis-
ter purge valve and the EVAP vent solenoid are turned
on, allowing the engine to draw a small vacuum on the
entire EVAP system. After the desired vacuum level has
been achieved, the EVAP canister purge valve is turned
OFF, sealing the system. If a sufficient vacuum level
cannot be achieved, a large leak is indicated. This can
be caused by the following conditions :
Missing or faulty fuel cap.
Disconnected or faulty fuel tank pressure sensor.
Disconnected, damaged, pinched, or blocked EVAP
purge line.
Disconnected or faulty EVAP canister purge valve.
Disconnected or faulty EVAP vent solenoid.Open ignition feed circuit to the EVAP vent or purge so-
lenoid.
Damaged EVAP canister.
Leaking fuel sensor assembly O-ring.
Leaking fuel tank or fuel filler beck.
Any of the above conditions can set DTC P0444.
The test is failed if the tank vacuum is less than 10 in
H20 for 15 seconds and the manifold vacuum integral is
greater than 49512 (proportional to purge mass from the
tank).
Conditions for Setting the DTC
Intake Air Temperature(IAT) is between 4°C and
34°C(39°F and 93°F).at engine start up.
Engine Coolant Temperature(ECT) is between 4°C
and 34°C(39°F and 93°F).at engine start up.
Barometric pressure (BARO) is greater than 68kPA.
IAT is not more than 8°C(46°F) greater than the ECT
at start up.
Fuel level is between 10% and 90%.
The throttle position (TP) sensor is less than or equal
to 100%.
No fuel slosh, and the change in fuel level percent is
21 counts on 0.125 sec.
Manifold vacuum is greater than or equal to 10kPA.
Fuel level or change in tank pressure is less than or
equal to 24.9 in H2O.
System voltage is between 11V and 16V.
1F–214 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F240
DIAGNOSTIC TROUBLE CODE (DTC) – P0445 EVAP PURGE CONTROL
CIRCUIT FAULT
Circuit Description
The evaporative emission (EVAP) system includes the
following components :
Fuel tank.
EVAP vent solenoid.
Fuel tank pressure sensor.
Fuel pipes and hoses.
Fuel vapor lines.
Fuel cap.
EVAP canister.
Purge lines.
EVAP canister purge valve.
EVAP service port.
The evaporative emission system is checked by apply-
ing vacuum to the EVAP system and monitoring for a
vacuum decay. The engine control module(ECM) moni-
tors the vacuum level through the fuel tank pressure
sensor signal. At the appropriate time, the EVAP canis-
ter purge valve and the EVAP vent solenoid are turned
on, allowing the engine to draw a small vacuum on the
entire EVAP system. After the desired vacuum level has
been achieved, the EVAP canister purge valve is turned
OFF, sealing the system. If a sufficient vacuum level
cannot be achieved, a large leak is indicated. This can
be caused by the following conditions :
Missing or faulty fuel cap.
Disconnected or faulty fuel tank pressure sensor.
Disconnected, damaged, pinched, or blocked EVAP
purge line.
Disconnected or faulty EVAP canister purge valve.Disconnected or faulty EVAP vent solenoid.
Open ignition feed circuit to the EVAP vent or purge so-
lenoid.
Damaged EVAP canister.
Leaking fuel sensor assembly O-ring.
Leaking fuel tank or fuel filler beck.
Any of the above conditions can set DTC P0445.
The test is failed if the tank vacuum is less than 10 in
H20 for 15 seconds and the manifold vacuum integral is
greater than 49512 (proportional to purge mass from the
tank).
Conditions for Setting the DTC
Intake Air Temperature(IAT) is between 4°C and
34°C(39°F and 93°F).at engine start up.
Engine Coolant Temperature(ECT) is between 4°C
and 34°C(39°F and 93°F).at engine start up.
Barometric pressure (BARO) is greater than 68kPA.
IAT is not more than 8°C(46°F) greater than the ECT
at start up.
Fuel level is between 10% and 90%.
The throttle position (TP) sensor is less than or equal
to 100%.
No fuel slosh, and the change in fuel level percent is
21 counts on 0.125 sec.
Manifold vacuum is greater than or equal to 10kPA.
Fuel level or change in tank pressure is less than or
equal to 24.9 in H2O.
System voltage is between 11V and 16V.
1F–296 ENGINE CONTROLS
DAEWOO M-150 BL2
POOR FUEL ECONOMY
Definition: Fuel economy, as measured by an actual
road test, is noticeably lower than expected. Also, fuel
economy is noticeably lower than it was on this vehicle
at one time, as previously shown by an actual road test.
Important: Driving habits affect fuel economy. Check
the owner’s driving habits by asking the following ques-
tions:1. Is the A/C system (i.e. defroster mode) turned on all
the time?
2. Are the tires at the correct air pressure?
3. Have excessively heavy loads been carried?
4. Does the driver accelerate too much and too often?
Suggest the driver read the section in the owner’s
manual about fuel economy.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Inspect the air filter for excessive contamination.
2. Inspect for fuel system leaks.
Are all needed checks complete?
–
Go to Step 3
–
3
1. Inspect the spark plugs for excessive wear,
insulation cracks, improper gap, or heavy
deposits.
2. Replace any faulty spark plugs.
3. Inspect the ignition wires for cracking, hardness,
and proper connections.
Are all needed checks and repairs complete?
–
Go to Step 4
–
4
1. Inspect the engine coolant level.
2. Check the thermostat for being always open or for
an incorrect heat range.
3. Replace the thermostat as needed.
Are all needed checks and repairs complete?
–
Go to Step 4
–
5
1. Check the transaxle shift pattern. Ensure all
transaxle gears are functioning.
2. Check for proper calibration of the speedometer.
3. Check the brakes for dragging.
4. Check the cylinder compression.
5. Repair, replace, or adjust any components as
needed.
Are all checks and needed repairs complete?
–
System OK
–
DAEWOO M-150 BL2
SECTION 2A
SUSPENSION DIAGNOSIS
TABLE OF CONTENTS
Diagnostic Information and Procedures 2A-1. . . . .
General Diagnosis 2A-1. . . . . . . . . . . . . . . . . . . . . . . . . Wheel Bearing Diagnosis 2A-6. . . . . . . . . . . . . . . . . . .
DIAGNOSTIC INFORMATION AND PROCEDURES
GENERAL DIAGNOSIS
Problems in the steering, the suspension, the tires, and
the wheels involve several systems. Consider all sys-
tems when you diagnose a complaint. Some problems,
such as abnormal or excessive tire wear and scuffed
tires, may be the result of hard driving. Always road testthe vehicle first. If possible, do this road test with the
customer.
Proceed with the following preliminary checks. Correct
any substandard conditions.
Application Checks Correction
Preliminary ChecksInspect the tires for improper pressure
and uneven wear.Inflate the tires to the proper pressure.
Inspect the joint from the steering
column to the intermediate shaft for
loose connections or wear.
Inspect the joint from the intermediate
shaft to the steering gear for loose
connections or wear.Tighten the coupling flange pinch
bolts.
Replace the intermediate shaft as
needed.
Inspect the front and the rear
suspension, the steering gear, and the
linkage for loose or damaged parts.Tighten the front and the rear
suspension.
Tighten the steering gear mounting
bracket bolts.
Replace the front and the rear
suspension as needed.
Replace the steering gear as needed.
Replace the coupling flange as
needed.
Inspect for out–of–round tires.Perform free runout test.
Match–mount the tires.
Inspect for out–of–balance tires, bent
wheels, and worn or loose wheel
bearings.Balance the wheels.
Replace the wheels.
Replace the wheel bearings.
Check the power steering pump drive
belt tension.Tighten the power steering pump drive
belt.
Inspect the power steering system.
Also, check the power steering fluid
level.Repair any leaks.
Perform a power steering gear test.
Add power steering fluid.