
ENGINE CONTROLS 1F–279
DAEWOO M-150 BL2
DTC P1661 – Malfunction Indicator Lamp (MIL) Low Voltage
StepActionValue(s)YesNo
1
Perform an On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2
1. Turn the ignition switch to LOCK.
2. Disconnect the cluster wiring connector.
3. With the test light, connected to ground, probe
the ignition feed circuit, at terminal A7 in the
harness connector.
Does the resistance within the specified value?
–
Go to Step 3Go to Step 6
3
1. Turn the ignition switch to LOCK.
2. With the test light, connected to ground, probe
the ignition feed circuit, at ECM wiring connector
terminal 39.
Does the test light illuminate?
–
Go to Step 4Go to Step 5
4
1. Turn the ignition switch to LOCK.
2. Replace the cluster.
Is the replacement complete?
–
Go to Step 6
–
5
Repair a short to ground or open between the ECM
wiring connector terminal 39 and cluster wiring
connector terminal A7.
Is the repair complete?
–
Go to Step 6
–
6
1. Using the scan tool, clear the Diagnostic Trouble
Codes(DTCs)
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?
–
Go to Step 7Go to Step 2
7
Check if any additional DTCs are set.
Are any DTCs displayed that that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK

ENGINE CONTROLS 1F–281
DAEWOO M-150 BL2
INTERMITTENT
Definition: The problem may or may not illuminate the
Malfunction Indicator Lamp (MIL) or store a Diagnostic
Trouble Code (DTC).
Important: Do not use the Diagnostic Trouble Code
(DTC) tables for intermittent problems. A fault must bepresent in order to locate the problem. If a fault is inter-
mittent, use of Diagnostic Trouble Code tables may re-
sult in the replacement of good parts.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Perform a careful inspection of any suspect
circuits.
2. Inspect for poor mating of the connector halves,
or terminals not fully seated into the connector
body.
3. Inspect for improperly formed or damaged
terminals.
4. Inspect for poor terminal-to-wire connections.
This requires removing the terminal from the
connector body to inspect it.
Are any problems present?
–
Go to Step 3Go to Step 4
3Repair the electrical connections as needed.
Is the repair complete?–System OK–
4
Road test the vehicle with a voltmeter connected to
a suspected circuit or a scan tool connected to the
Data Link Connector (DLC).
Did the voltmeter or the scan tool indicate an
abnormal voltage or scan reading?
–
Go to Step 5Go to Step 6
5
Replace the sensor in the affected circuit, if a
Diagnostic Trouble Code (DTC) was stored for this
circuit (except for the DTCs P0171 and P0172).
Is the repair complete?
–
System OK
–
6Does an intermittent Malfunction Indicator Lamp
(MIL) or DTC occur?–Go to Step 7Go to Step 8
7
1. Check for a faulty relay, Engine Control Module
(ECM) driven solenoid, or switch.
2. Check for improper installation of electrical
devices, such as lights, two-way radios, electric
motors, etc.
3. Inspect the ignition control wires for proper
routing (away from ignition wires, ignition system
components, and the generator).
4. Check for a short-to-ground in the MIL circuit or
the DLC “test” terminal.
5. Inspect the ECM ground connections.
6. Correct or repair the affected circuits as needed.
Is the repair complete?
–
System OK
–
8
1. Check for a loss of DTC memory.
2. Disconnect the throttle position (TP) sensor.
3. Run the engine at idle until the MIL comes on.
4. Turn the ignition OFF.
Is DTC P0122 stored in memory?
–
Go to Step 10Go to Step 9

1F–284 ENGINE CONTROLS
DAEWOO M-150 BL2
Hard Start (Cont’d)
StepActionValue(s)YesNo
10
1. Check the fuel injector driver circuit.
2. Disconnect all of the fuel injector harness
connectors at the fuel injectors.
3. Connect an injector test light between the
harness terminals of each fuel injector connector.
4. Note the test light while cranking the engine.
Does the test light blink at all connectors?
–
Go to Step 13Go to Step 11
11
Check the fuel injector driver wiring harness, the
connectors, and the connector terminals for the
proper connections.
Is the problem found?
–
Go to Step 12Go to Step 28
12
Repair the wiring harness, the connector, or the
connector terminal as needed.
Is the repair complete?
–
System OK
–
13
Measure the resistance of each fuel injector.
Is the fuel injector resistance within the value
specified at 20C (68F)
Note: The resistance will increase slightly at higher
temperatures)?
11.6–12.4 ΩGo to Step 15Go to Step 14
14
Replace any fuel injector with a resistance that is out
of specifications.
Is the repair complete?
–
System OK
–
15Perform an injector diagnosis.
Is the problem found?–Go to Step 16Go to Step 17
16
Replace any restricted or leaking fuel injectors as
needed.
Is the repair complete?
–
System OK
–
17
1. Check for the proper ignition voltage output for
each cylinder with a spark tester.
2. Inspect the spark plugs for cracks, wear, improper
gap, burned electrodes, or heavy deposits.
3. Inspect the ignition wires for short conditions.
4. Inspect all of the ignition grounds for loose
connections.
5. Inspect the Engine Control Module (ECM) for the
proper operation.
Is the problem found?
–
Go to Step 18Go to Step 19
18Correct or replace any faulty ignition components.
Is the repair complete?–System OK–
19Does the engine misfire or cut out under load or at
idle?–Go to “Ignition
System Check”
Go to Step 20
20Does the engine start, but then immediately stall?–Go to Step 21Go to Step 23
21
1. Remove the Crankshaft Position (CKP) sensor.
2. Inspect for faulty connections and repair as
needed.
Is the problem found?
–
Go to Step 22Go to Step 25
22Repair the faulty connections as needed.
Is the repair complete?–System OK–

1F–292 ENGINE CONTROLS
DAEWOO M-150 BL2
HESITATION, SAG, STUMBLE
Definition: Momentary lack of response as the accelera-
tor is pushed down. This can occur at any vehicle speed.
It is usually the most severe when first trying to make the
vehicle move, as from a stop. Hesitation, sag, or
stumble may cause the engine to stall if severe enough.Important: Before diagnosing this condition, check ser-
vice bulletins for PROM updates.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Check the fuel system pressure. If the pressure is
not within the value specified, service the fuel
system as needed.
2. Inspect the Throttle Position (TP) sensor for
binding or sticking. The TP sensor voltage should
increase at a steady rate as the throttle is moved
toward Wide Open Throttle (WOT).
Is the problem found?
380 kPa
(55 psi)
Go to Step 3Go to Step 4
3Repair or replace any components as needed.
Is the repair complete?–System OK–
4
1. Check the Manifold Absolute Pressure (MAP)
sensor response and accuracy.
2. Inspect the fuel for water contamination.
3. Check the Evaporative Emission (EVAP) Canister
Purge System for proper operation.
Is the problem found?
–
Go to Step 5Go to Step 6
5Repair or replace any components as needed.
Is the repair complete?–System OK–
6
1. Disconnect all of the fuel injector harness
connectors.
2. Connect an injector test light between the
harness terminals of each fuel injector.
3. Note the test light while cranking the engine.
Does the test light blink on all connectors?
–
Go to Step 8Go to Step 7
7
1. Repair or replace the faulty fuel injector drive
harness, the connector, or the connector terminal.
2. If the connections and the harnesses are good,
replace the Engine Control Module (ECM).
Is the repair complete?
–
System OK
–
8
Measure the resistance of each fuel injector.
Is the fuel injector resistance within the value
specified (the resistance will increase slightly at
higher temperatures)?
11.6–12.4 ΩGo to Step 10Go to Step 9
9
Replace any of the fuel injectors with a resistance
that is out of specifications.
Is the repair complete?
–
System OK
–
10Perform an injector diagnosis.
Is the problem found?–Go to Step 11Go to Step 12
11Replace any restricted or leaking fuel injectors.
Is the repair complete?–System OK–
12
Check the fuel system pressure after a cold start or
during moderate or full throttle acceleration.
Is the fuel pressure within specifications?
380 kPa
(55 psi)
Go to Step 14Go to Step 13

1F–294 ENGINE CONTROLS
DAEWOO M-150 BL2
CUTS OUT, MISSES
Definition: Steady pulsation or jerking that follows en-
gine speed, usually more pronounced as engine load in-creases. The exhaust has a steady spitting sound at idle
or low speed.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
Check the ignition system voltage output for all of
the cylinders using a spark tester.
Is spark present on all of the cylinders?
–
Go to Step 3
Go to “Ignition
System Check”
3
1. Inspect the spark plugs for excessive wear,
insulation cracks, improper gap, or heavy
deposits.
2. Check the resistance of the ignition wires.
Replace any ignition wires that have a resistance
greater than the value specified.
Is the problem found?
30000 ΩGo to Step 4Go to Step 5
4Repair or replace any components as needed.
Is the repair complete?–System OK–
5
With the engine running, spray the ignition wires with
a fine water mist to check for arcing and shorting to
ground.
Is the problem found?
–
Go to Step 6Go to Step 7
6Replace the ignition wires.
Is the repair complete?–System OK–
7
1. Perform a cylinder compression test.
2. If the compression is low, repair the engine as
needed.
3. Inspect for proper valve timing, bent pushrods,
worn rocker arms, broken or weak valve springs,
and worn camshaft lobes.
4. Inspect the intake manifold and the exhaust
manifold passages for casting flash.
Is the problem found?
–
Go to Step 8Go to Step 9
8Repair or replace any components as needed.
Is the repair complete?–System OK–
9
1. Check the fuel system for a plugged in-line fuel
filter.
2. Check the fuel system for low fuel pressure. If the
fuel pressure is below the value specified, service
the fuel system as needed.
3. Inspect for contaminated fuel.
Is the problem found?
380 kPa
(55 psi)
Go to Step 10Go to Step 11
10Repair or replace any components as needed.
Is the repair complete?–System OK–
11
1. Disconnect all of the fuel injector harness
connectors at the fuel injectors.
2. Connect an injector test light to the harness
terminals of each fuel injector connector.
3. Note the test light while cranking the engine for
each fuel injector.
Does the test light blink for all of the fuel injectors?
–
Go to Step 13Go to Step 12

ENGINE CONTROLS 1F–295
DAEWOO M-150 BL2
Cuts Out, Misses (Cont’d)
StepActionValue(s)YesNo
12
1. Repair or replace the faulty injector drive circuit
harness, the connector, or the connector terminal.
2. If the connections and the harnesses are good,
replace the Engine Control Module (ECM).
Is the repair complete?
–
System OK
–
13
Measure the resistance of each fuel injector.
Is the injector resistance within the value specified
(the resistance will increase slightly at higher
temperatures)?
11.6–12.4 ΩGo to Step 15Go to Step 14
14
Replace any fuel injectors with a resistance that is
out of specifications.
Is the repair complete?
–
System OK
–
15Perform an injector diagnosis.
Is the problem found?–Go to Step 16Go to Step 17
16Replace any restricted or leaking fuel injectors.
Is the repair complete?–System OK–
17
1. Check for electromagnetic interference.
2. Monitor the engine rpm with a scan tool.
Does the scan tool rpm change greatly with little
change in actual engine rpm?
–
Go to Step 18
–
18
1. Inspect the routing of the ignition wires.
2. Inspect all of the ignition system grounds.
3. Correct the routing or repair the ground
connections as needed.
Are all checks and needed repairs complete?
–
System OK
–

1F–298 ENGINE CONTROLS
DAEWOO M-150 BL2
Rough, Unstable, or Incorrect Idle, Stalling (Cont’d)
StepActionValue(s)YesNo
12
Is the long term fuel trim reading below the value
specified?
–20%
Go to
“Diagnostic Aids
for DTC P0172”
Go to Step 13
13
Is the long term fuel trim reading above the value
specified?
25%
Go to
“Diagnostic Aids
for DTC P0171”
–
14
1. Disconnect all of the fuel injector harness
connectors at the fuel injectors.
2. Connect an injector test light between the
harness terminals of each fuel injector connector.
3. Note the test light while cranking the engine.
Does the test light blink for all of the fuel injectors?
–
Go to Step 16Go to Step 15
15
1. Repair or replace the faulty injector drive circuit
harness, the connector, or the connector
terminals as needed.
2. If the harness, the connectors, and the terminals
are OK, replace the Engine Control Module
(ECM).
Is the repair complete?
–
System OK
–
16
Measure the resistance of each of the fuel injectors.
Is the resistance within the value specified (the
resistance will increase slightly at higher
temperatures)?
11.6–12.4 ΩGo to Step 18Go to Step 17
17
Replace any fuel injectors with a resistance that is
out of specifications.
Is the repair complete?
–
System OK
–
18Perform an injector diagnosis.
Is the problem found?–Go to Step 19Go to Step 20
19Replace any leaking or restricted fuel injectors.
Is the repair complete?–System OK–
20
1. With the engine OFF, disconnect the fuel
pressure regulator vacuum hose.
2. Thoroughly inspect the fuel pressure regulator
vacuum port and the fuel pressure regulator
vacuum hose for the presence of fuel.
Is the problem found?
–
Go to Step 21Go to Step 22
21Replace the fuel pressure regulator as needed.
Is the repair complete?–System OK–
22
1. Check the ignition system output voltage for all of
the cylinders using a spark tester.
2. Inspect the spark plugs for excessive wear,
insulation cracks, improper gap, or heavy
deposits.
3. Inspect the ignition wires for cracking, hardness,
or improper connections.
4. Replace any ignition wires with a resistance over
the value specified.
Is the problem found?
30000 ΩGo to Step 23Go to Step 24
23
Repair or replace any ignition system components
as needed.
Is the repair complete?
–
System OK
–

4A –4 HYDRAULIC BRAKES
DAEWOO M-150 BL2
DIAGNOSITIC INFORMATION AND PROCEDURES
BRAKE SYSTEM TESTING
(Left–Hand Drive Shown, Right–Hand
Drive Similar)
Brakes should be tested on a dry, clean, reasonably
smooth and level roadway. A true test of brake perfor-
mance cannot be made if the roadway is wet, greasy, or
covered with loose dirt whereby all tires do not grip the
road equally. Testing will also be adversely affected if the
roadway is crowned so as to throw the weight so roughly
that the wheels tend to bounce.
Test the brakes at different vehicle speeds with both light
and heavy pedal pressure; however, avoid locking the
brakes and sliding the tires. Locked brakes and sliding
tires do not indicate brake efficiency since heavily
braked, but turning, wheels will stop the vehicle in less
distance than locked brakes. More tire-to-road friction is
present with a heavily braked, turning tire than with a
sliding tire.
Because of the high deceleration capability, a firmer
pedal may be felt at higher deceleration levels.
There are three major external conditions that affect
brake performance:
Tires having unequal contact and grip of the road will
cause unequal braking. Tires must be equally in-
flated, and the tread pattern of the right and the left
tires must be approximately equal.
Unequal loading of the vehicle can affect the brake
performance since the most heavily loaded wheels
require more braking power, and thus more braking
effort, than the others.
Misalignment of the wheels, particularly conditions of
excessive camber and caster, will cause the brakes
to pull to one side.
To check for brake fluid leaks, hold constant foot pres-
sure on the pedal with the engine running at idle and the
shift lever in NEUTRAL. If the pedal gradually falls away
with the constant pressure, the hydraulic system may be
leaking. Perform a visual check to confirm any sus-
pected leaks.
Check the master cylinder fluid level. While a slight drop
in the reservoir level results from normal lining wear, an
abnormally low level indicates a leak in the system. The
hydraulic system may be leaking either internally or ex-
ternally. Refer to the procedure below to check the mas-
ter cylinder. Also, the system may appear to pass this
test while still having a slight leak. If the fluid level is nor-
mal, check the vacuum booster pushrod length. If an in-
correct pushrod length is found, adjust or replace the
rod.Check the master cylinder using the following proce-
dure:
Check for a cracked master cylinder casting or brake
fluid leaking around the master cylinder. Leaks are in-
dicated only if there is at least one drop of fluid. A
damp condition is not abnormal.
Check for a binding pedal linkage and for an incorrect
pushrod length. If both of these parts are in satisfac-
tory condition, disassemble the master cylinder and
check for an elongated or swollen primary cylinder or
piston seals. If swollen seals are found, substandard
or contaminated brake fluid should be suspected. If
contaminated brake fluid is found, all the components
should be disassembled and cleaned, and all the rub-
ber components should be replaced. All of the pipes
must also be flushed.
Improper brake fluid, or mineral oil or water in the fluid,
may cause the brake fluid to boil or cause deterioration
of the rubber components. If the primary piston cups in
the master cylinder are swollen, then the rubber parts
have deteriorated. This deterioration may also be evi-
denced by swollen wheel cylinder piston seals on the
drum brake wheels.
If rubber deterioration is evident, disassemble all the hy-
draulic parts and wash the parts with alcohol. Dry these
parts with compressed air before reassembly to keep al-
cohol out of the system. Replace all the rubber parts in
the system, including the hoses. Also, when working on
the brake mechanisms, check for fluid on the linings. If
excessive fluid is found, replace the linings.
If the master cylinder piston seals are in satisfactory
condition, check for leaks or excessive heat conditions.
If these conditions are not found, drain the fluid, flush the
master cylinder with brake fluid, refill the master cylin-
der, and bleed the system. Refer to “Manual Bleeding
the Brakes” in this section.
BRAKE HOSE INSPECTION
The hydraulic brake hoses should be inspected at least
twice a year. The brake hose assembly should be
checked for road hazard damage, cracks, chafing of the
outer cover, and for leaks or blisters. Inspect the hoses
for proper routing and mounting. A brake hose that rubs
on a suspension component will wear and eventually
fail. A light and a mirror may be needed for an adequate
inspection. If any of the above conditions are observed
on the brake hose, adjust or replace the hose as neces-
sary.