2003 DAEWOO MATIZ service

1E–2 ENGINE ELECTRICAL
DAEWOO M-150 BL2
DESCRIPTION AND OPERATION
BATTERY
The battery has three major functions in the electrical
system. First, the battery provides a source of energy
for cranking the engine. Second, the battery acts as a
voltage stabilizer for the electrical system. Finally, the
battery can, for a limited time, provide energy when the
electrical demand exceeds the output of the generator.
The sealed battery is standard on all cars. There are no
vent plugs in the cover. The battery is completely
sealed, except for two small vent holes in the sides.
These vent holes allow the small amount of gas pro-
duced in the battery to escape.
The sealed battery has the following advantages over
conventional batteries:

No water need be added for the life of the battery.

It is protected against overcharge. If too much volt-
age is applied to the battery, it will not accept as much
current as a conventional battery. In a conventional
battery, the excess voltage will still try to charge the
battery, leading to gassing, which causes liquid loss.

It is not as liable to self-discharge as a conventional
battery. This is particularly important when a battery
is left standing for long periods of time.

It has more power available in a lighter and a smaller
case.
RATINGS
A battery has two ratings: (1) A reserve capacity rating
designated at 27C (81F), which is the time a fully
charged battery will provide 25 amperes current flow at
or above 10.5 volts; (2) A cold cranking amp rating de-
termined under testing at -18C (0F), which indicates
the cranking load capacity.
RESERVE CAPACITY
The reserve capacity is the maximum length of time it is
possible to travel at night with the minimum electrical
load and no generator output. Expressed in minutes,
Reserve Capacity (or RC rating) is the time required for
a fully charged battery, at a temperature of 27C (81F)
and being discharged at a current of 25 amperes, to
reach a terminal voltage of 10.5 volts.
COLD CRANKING AMPERAGE
The cold cranking amperage test is expressed at a bat-
tery temperature of -18C (0F). The current rating is
the minimum amperage, which must be maintained by
the battery for 30 seconds at the specified temperature,
while meeting a minimum voltage requirement of
7.2 volts. This rating is a measure of cold cranking ca-
pacity.The battery is not designed to last indefinitely. However,
with proper care, the battery will provide many years of
service.
If the battery tests well, but fails to perform satisfactorily
in service for no apparent reason, the following factors
may point to the cause of the trouble:

Vehicle accessories are left on overnight.

Slow average driving speeds are used for short peri-
ods.

The vehicle’s electrical load is more than the genera-
tor output, particularly with the addition of aftermarket
equipment.

Defects in the charging system, such as electrical
shorts, a slipping generator belt, a faulty generator, or
a faulty voltage regulator.

Battery abuse, including failure to keep the battery
cable terminals clean and tight, or a loose battery
hold-down.

Mechanical problems in the electrical system, such
as shorted or pinched wires.
BUILT-IN HYDROMETER
The sealed battery has a built-in, temperature-compen-
sated hydrometer in the top of the battery. This hydrom-
eter is to be used with the following diagnostic
procedure:
1. When observing the hydrometer, make sure that the
battery has a clean top.
2. Under normal operation, two indications can be ob-
served:

GREEN DOT VISIBLE – Any green appearance is
interpreted as a “green dot,” meaning the battery is
ready for testing.

DARK GREEN DOT IS NOT VISIBLE – If there is
a cranking complaint, the battery should be tested.
The charging and electrical systems should also
be checked at this time.
3. Occasionally, a third condition may appear:

CLEAR OR BRIGHT YELLOW – This means the
fluid level is below the bottom of the hydrometer.
This may have been caused by excessive or pro-
longed charging, a broken case, excessive tipping,
or normal battery wear. Finding a battery in this
condition may indicate high charging by a faulty
charging system. Therefore, the charging and the
electrical systems may need to be checked if a
cranking complaint exists. If the cranking com-
plaint is caused by the battery, replace the battery.

1E–4 ENGINE ELECTRICAL
DAEWOO M-150 BL2
3. In both vehicles, apply the parking brake firmly.
Notice: Make sure the cables are not on or near pulleys,
fans, or other parts that will move when the engine
starts, damaging the parts.
4. Shift a manual transaxle to NEUTRAL.
Caution: Do not use cables that have loose or miss-
ing insulation, or injury could result.
5. Clamp one end of the first jumper cable to the positive
terminal on the battery. Make sure it does not touch
any other metal parts. Clamp the other end of the
same cable to the positive terminal on the other bat-
tery. Never connect the other end to the negative ter-
minal of the discharged battery.
Caution: Do not attach the cable directly to the neg-
ative terminal of the discharged battery. Doing so
could cause sparks and possible battery explosion.
6. Clamp one end of the second cable to the negative
terminal of the booster battery. Make the final con-
nection to a solid engine ground, such as the engine
lift bracket, at least 450 millimeters (18 inches) from
the discharged battery.
7. Start the engine of the vehicle with the good battery.
Run the engine at a moderate speed for several min-
utes. Then start the engine of the vehicle which has
the discharged battery.
8. Remove the jumper cables by reversing the above
sequence exactly. Remove the negative cable from
the vehicle with the discharged battery first. While re-
moving each clamp, take care that it does not touch
any other metal while the other end remains at-
tached
.
GENERATOR
The Delco-Remy CS charging system has several mod-
els available, including the ∅114D (A-type) or CS114D
(B-type). The number denotes the outer diameter in
millimeters of the stator lamination.
CS generators are equipped with internal regulators.
The Y connection (A-type) or Delta (B-type) stator, a
rectifier bridge, and a rotor with slip rings and brushes
are electrically similar to earlier generators. A conven-
tional pulley and fan are used. There is no test hole.
Unlike three-wire generators, the ∅114D (A-type) or
CS114D (B-type) may be used with only two connec-
tions: battery positive and an ‘‘L’’ terminal to the charge
indicator lamp.
As with other charging systems, the charge indicator
lamp lights when the ignition switch is turned to ON, and
goes out when the engine is running. If the charge indi-
cator is on with the engine running, a charging system
defect is indicated.
The regulator voltage setting varies with temperature
and limits the system voltage by controlling the rotorfield current. The regulator switches rotor field current
on and off. By varying the on-off time, correct average
field current for proper system voltage control is ob-
tained. At high speeds, the on-time may be 10 percent
and the off-time 90 percent. At low speeds, with high
electrical loads, on-time may be 90 percent and the off-
time 10 percent.
CHARGING SYSTEM
The Delco-Remy CS charging system has several mod-
els available, including the ∅114D (A-type) or CS114D
(B-type). The number denotes the outer diameter in
millimeters of the stator laminations.
CS generators use a new type of regulator that incorpo-
rates a diode trio. The Y connection (A-type) or Delta (B-
type) stator, a rectifier bridge, and a rotor with slip rings
and brushes are electrically similar to earlier generators.
A conventional pulley and fan are used. There is no test
hole.
STARTER
Wound field starter motors have pole pieces, arranged
around the armature, which are energized by wound
field coils.
Enclosed shift lever cranking motors have the shift lever
mechanism and the solenoid plunger enclosed in the
drive housing, protecting them from exposure to dirt, icy
conditions, and splashes.
In the basic circuit, solenoid windings are energized
when the switch is closed. The resulting plunger and
shift lever movement causes the pinion to engage the
engine flywheel ring gear. The solenoid main contacts
close. Cranking then takes place.
When the engine starts, pinion overrun protects the ar-
mature from excessive speed until the switch is opened,
at which time the return spring causes the pinion to dis-
engage. To prevent excessive overrun, the switch
should be released immediately after the engine starts.
STARTING SYSTEM
The engine electrical system includes the battery, the
ignition, the starter, the generator, and all the related wir-
ing. Diagnostic tables will aid in troubleshooting system
faults. When a fault is traced to a particular component,
refer to that component section of the service manual.
The starting system circuit consists of the battery, the
starter motor, the ignition switch, and all the related elec-
trical wiring. All of these components are connected
electrically
.
DISTRIBUTOR
Distributor distributes the high tension voltage induced
from ignition coil, to each spark plug of each cylinder in

1E–12 ENGINE ELECTRICAL
DAEWOO M-150 BL2
BATTERY LOAD TEST
1. Check the battery for obvious damage, such as a
cracked or broken case or cover, which could permit
the loss of electrolyte. If obvious damage is noted, re-
place the battery.
Caution: Do not charge the battery if the hydrometer
is clear or light yellow. Instead, replace the battery. If
the battery feels hot or if violent gassing or spewing
of electrolyte through the vent hole occurs, discontin-
ue charging or reduce the charging rate to avoid inju-
ry.
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 apply
a 270-ampere load.
Important: The battery temperature must be estimated
by touch and by the temperature condition the battery
has been exposed to 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, replace
the battery. Refer to “Battery Specifications” in this
section.
GENERATOR OUTPUT TEST
1. Perform the generator system test. Refer to “Gener-
ator System Check” in this section.
2. Replace the generator if it fails that test. Refer to
“Generator” in the On-Vehicle Service section. If it
passes the test, perform the on-vehicle output
check which follows.
Important: Always check the generator for output be-
fore assuming that a grounded “L” terminal circuit has
damaged the regulator.
3. Attach a digital multimeter (a), an ammeter (b), and
a carbon pile load (c) to the battery (d) and the gen-
erator (e) of the rehicle.
D102E301
Important: Be sure the vehicle battery is fully charged,
and the carbon pile load is turned off.
4. With the ignition switch in the OFF position, check
and record the battery voltage.
5. Remove the harness connector from the generator.
6. Turn the ignition switch to the ON position with the
engine not running. Use a digital multimeter to
check for voltage in the harness connector “L” termi-
nal.
7. The reading should be near the specified battery
voltage of 12 volts. If the voltage is too low, check
the indicator “L” terminal circuits for open and
grounded circuits causing voltage loss. Correct any
open wires, terminal connections, etc., as neces-
sary. Refer to “Charging System” in this section.
8. Attach the generator harness connector.
9. Run the engine at a moderate idle, and measure the
voltage across the battery terminals. The reading
should be above that recorded in Step 4 but less
than 15 volts. If the reading is over 15 volts or below
the previous reading, replace the generator. Refer to
“Generator” in the On-Vehicle Service section.
10. Run the engine at a moderate idle, and measure the
generator amperage output.
11. Turn on the carbon pile, and adjust it to obtain the
maximum amps while maintaining the battery volt-
age above 13 volts.
12. If the reading is within 15 amps of the generator’s
rating noted on the generator, the generator is good.
If not, replace the generator. Refer to “Generator”
in the On-Vehicle Service section.
13. With the generator operating at the maximum out-
put, measure the voltage between the generator
housing and the battery negative terminal. The volt-
age drop should be 0.5 volt or less. If the voltage
drop is more than 0.5 volt, check the ground path
from the generator housing to the negative battery
cable.
14. Check, clean, tighten, and recheck all of the ground
connections.

ENGINE ELECTRICAL 1E–13
DAEWOO M-150 BL2
GENERATOR SYSTEM CHECK
When operating normally, the generator indicator lamp
will come on when the ignition switch is in the ON posi-
tion and go out when the engine starts. If the lamp oper-
ates abnormally or if an undercharged or overcharged
battery condition occurs, the following procedure may
be used to diagnose the charging system. Remember
that an undercharged battery is often caused by acces-
sories being left on overnight or by a defective switch
that allows a lamp, such as a trunk or glove box lamp, to
stay on.
Diagnose the generator with the following procedure:
1. Visually check the belt and wiring.
2. With the ignition switch in the ON position and the en-
gine stopped, the charge indicator lamp should be on.
If not, detach the harness at the generator and
ground the ‘‘L’’ terminal in the harness with a fused,
5-ampere jumper lead.
If the lamp lights, replace the generator. Refer to
“Generator” in the On-Vehicle Service section.

If the lamp does not light, locate the open circuit
between the ignition switch and the harness con-
nector. The indicator lamp bulb may be burned out.
3. With the ignition switch in the ON position and the en-
gine running at moderate speed, the charge indicator
lamp should be off. If not, detach the wiring harness
at the generator.

If the lamp goes off, replace the generator. Refer to
“Generator” in the On-Vehicle Service section.

If the lamp stays on, check for a short to ground in
the harness between the connector and the indica-
tor lamp.
Important: Always check the generator for output be-
fore assuming that a grounded ‘‘L’’ terminal circuit has
damaged the regulator. Refer to “Generator” in the Unit
Repair section.

1E–14 ENGINE ELECTRICAL
DAEWOO M-150 BL2
REPAIR INSTRUCTIONS
ON–VEHICLE SERVICE
D12E5011
STARTER
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the electrical connector and clip around
the starter.

Remove the engine oil temperature sensor to dis-
connect the harness connector (1).

Remove the starter solenoid nut to disconnect the
electrical cable (2).

Remove the harness clip bolt to disconnect the
harness clip (3).

Remove the ground bolt (4).
D102E502
3. Remove the starter assembly.

Remove the starter mounting bolts (1).

Remove the starter assembly (2).
D12E5031
Installation procedure
1. Install in the reverse order of removal.
2. Install the starter mounting bolts and starter solenoid
nut.
Tighten

Tighten the starter mounting bolts to 55–65 Nm
(41–48 lb-ft) (a).

Tighten the starter solenoid nut to 9–12 Nm
(80–106 lb-in) (b).

Tighten the harness clip bolt to 9–12 Nm (80–106
lb-in) (c).

Tighten the ground bolt to 35–41 Nm (26–30 lb-ft)
(d).

DAEWOO M-150 BL2
SECTION 1F
ENGINE CONTROLS
CAUTION: Disconnect the negative battery cable before removing or installing any electrical unit or when a
tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable
will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless
otherwise noted.
TABLE OF CONTENTS
Description and Operation 1F-4. . . . . . . . . . . . . . . . . .
Ignition System Operation 1F-4. . . . . . . . . . . . . . . . . .
Electronic Ignition System Ignition Coil 1F-4. . . . . . .
Crankshaft Position Sensor 1F-4. . . . . . . . . . . . . . . . .
Camshaft Position Sensor 1F-4. . . . . . . . . . . . . . . . . .
Idle Air System Operation 1F-4. . . . . . . . . . . . . . . . . .
Fuel Control System Operation 1F-4. . . . . . . . . . . . . .
Evaporative Emission Control System
Operation 1F-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controlled Charcoal Canister 1F-5. . . . . . . . . . . . . . . .
Positive Crankcase Ventilation Control System
Operation 1F-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Coolant Temperature Sensor 1F-6. . . . . . . . .
Throttle Position Sensor 1F-6. . . . . . . . . . . . . . . . . . . .
Catalyst Monitor Oxygen Sensors 1F-6. . . . . . . . . . .
Electric Exhaust Gas Recirculation Valve 1F-6. . . . .
Intake Air Temperature Sensor 1F-7. . . . . . . . . . . . . .
Idle Air Control Valve 1F-7. . . . . . . . . . . . . . . . . . . . . .
Manifold Absolute Pressure Sensor 1F-7. . . . . . . . . .
Engine Control Module 1F-8. . . . . . . . . . . . . . . . . . . . .
Fuel Injector 1F-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Cutoff Switch (Inertia Switch) 1F-8. . . . . . . . . . .
Knock Sensor 1F-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Variable Reluctance (VR) Sensor 1F-8. . . . . . . . . . . .
Octane Number Connector 1F-8. . . . . . . . . . . . . . . . .
Strategy-Based Diagnostics 1F-9. . . . . . . . . . . . . . . .
EOBD Serviceability Issues 1F-9. . . . . . . . . . . . . . . . .
Serial Data Communications 1F-10. . . . . . . . . . . . . . .
Euro On-Board Diagnostic (EOBD) 1F-10. . . . . . . . .
Comprehensive Component Monitor Diagnostic
Operation 1F-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Common EOBD Terms 1F-11. . . . . . . . . . . . . . . . . . . .
DTC Types 1F-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reading Diagnostic Trouble Codes 1F-13. . . . . . . . .
Primary System-Based Diagnostics 1F-15. . . . . . . . Diagnostic Information and Procedures 1F-17. . . .
System Diagnosis 1F-17. . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Aids 1F-17. . . . . . . . . . . . . . . . . . . . . . . . . .
Idle Learn Procedure 1F-17. . . . . . . . . . . . . . . . . . . . .
Euro On-Board Diagnostic (EOBD) System
Check 1F-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ECM Output Diagnosis 1F-20. . . . . . . . . . . . . . . . . . . .
Multiple ECM Information Sensor DTCs Set 1F-21. .
Engine Cranks But Will Not Run 1F-25. . . . . . . . . . . .
No Malfunction Indicator Lamp 1F-30. . . . . . . . . . . . .
Malfunction Indicator Lamp On Steady 1F-32. . . . . .
Fuel System Diagnosis 1F-34. . . . . . . . . . . . . . . . . . . .
Fuel Pump Relay Circuit Check 1F-36. . . . . . . . . . . .
Main Relay Circuit Check 1F-38. . . . . . . . . . . . . . . . . .
Manifold Absolute Pressure Check 1F-40. . . . . . . . . .
Idle Air Control System Check 1F-42. . . . . . . . . . . . .
Ignition System Check 1F-45. . . . . . . . . . . . . . . . . . . .
Engine Cooling Fan Circuit Check 1F-48. . . . . . . . . .
Data Link Connector Diagnosis 1F-52. . . . . . . . . . . . .
Fuel Injector Balance Test 1F-54. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code Diagnosis 1F-55. . . . . . . .
Clearing Trouble Codes 1F-55. . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Codes 1F-55. . . . . . . . . . . . . . . . .
DTC P0107 Manifold Absolute Pressure Sensor
Low Voltage 1F-58. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0108 Manifold Pressure Sensor High
Voltage 1F-62. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0112 Intake Air Temperature Sensor Low
Voltage 1F-66. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0113 Intake Air Temperature Sensor High
Voltage 1F-68. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0117 Engine Coolant Temperature Sensor
Low Voltage 1F-72. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0118 Engine Coolant Temperature Sensor
High Voltage 1F-74. . . . . . . . . . . . . . . . . . . . . . . . . . .

ENGINE CONTROLS 1F–3
DAEWOO M-150 BL2
DTC P1628 Immobilizer No Successful
Communication 1F-270. . . . . . . . . . . . . . . . . . . . . . .
DTC P1629 Immovilizer Wrong Computation 1F-272
DTC P0656 Fuel Level Gauge Circuit Fault 1F-274.
DTC P1660 Malfunction Indicator Lamp (MIL)
High Voltage 1F-276. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1661 Malfunction Indicator Lamp (MIL)
Low Voltage 1F-278. . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom Diagnosis 1F-280. . . . . . . . . . . . . . . . . . . . . .
Important Preliminary Checks 1F-280. . . . . . . . . . . . .
Intermittent 1F-281. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hard Start 1F-283. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surges or Chuggles 1F-286. . . . . . . . . . . . . . . . . . . . .
Lack of Power, Sluggishness or Sponginess 1F-288
Detonation/Spark Knock 1F-290. . . . . . . . . . . . . . . . . .
Hesitation, Sag, Stumble 1F-292. . . . . . . . . . . . . . . . .
Cuts Out, Misses 1F-294. . . . . . . . . . . . . . . . . . . . . . . .
Poor Fuel Economy 1F-296. . . . . . . . . . . . . . . . . . . . . .
Rough, Unstable, or Incorrect Idle, Stalling 1F-297. .
Excessive Exhaust Emissions or Odors 1F-300. . . .
Dieseling, Run-on 1F-302. . . . . . . . . . . . . . . . . . . . . . .
Backfire 1F-303. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance and Repair 1F-304. . . . . . . . . . . . . . . . . .
On-Vehicle Service 1F–304 . . . . . . . . . . . . . . . . . . . . . . .
Fuel Pump 1F–304 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Pressure Regulator 1F-305. . . . . . . . . . . . . . . . .
Fuel Filter 1F-306. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Tank 1F-307. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Rail and Injectors 1F-308. . . . . . . . . . . . . . . . . . .
Evaporator Emission Canister 1F-309. . . . . . . . . . . . . Evaporator Emission Canister Purge
Solenoid 1F-310. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manifold Absolute Pressure (MAP) Sensor 1F-310. .
Throttle Body 1F-311. . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Coolant Temperature (ECT) Sensor 1F-312.
Intake Air Temperature (ECT) Sensor 1F-313. . . . . .
Oxygen Sensor (O2S 1) 1F-314. . . . . . . . . . . . . . . . . .
Heated Oxygen Sensor (HO2S 2) 1F-314. . . . . . . . .
Electric Exhaust Gas Recirculation (EEGR)
Valve 1F-315. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Knock Sensor 1F-315. . . . . . . . . . . . . . . . . . . . . . . . . . .
Electronic Ignition (EI) System Ignition Coil 1F-316.
Crankshaft Position (CKP) Sensor 1F-316. . . . . . . .
Camshaft Position (CMP) Sensor 1F-317. . . . . . . . . .
Engine Control Module (ECM) 1F-317. . . . . . . . . . . . .
Specifications 1F-319. . . . . . . . . . . . . . . . . . . . . . . . . . .
Fastener Tightening Specification 1F-319. . . . . . . . . .
Special Tools 1F-319. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special Tools Table 1F-319. . . . . . . . . . . . . . . . . . . . . .
Schematic and Routing Diagrams 1F-320. . . . . . . . .
ECM Wiring Diagram
(Sirius D3 – 1 of 5) 1F-320. . . . . . . . . . . . . . . . . . . .
ECM Wiring Diagram
(Sirius D3 – 2 of 5) 1F-321. . . . . . . . . . . . . . . . . . . .
ECM Wiring Diagram
(Sirius D3 – 3 of 5) 1F-322. . . . . . . . . . . . . . . . . . . .
ECM Wiring Diagram
(Sirius D3 – 4 of 5) 1F-323. . . . . . . . . . . . . . . . . . . .
ECM Wiring Diagram
(Sirius D3 – 5 of 5) 1F-324. . . . . . . . . . . . . . . . . . . .

1F–4 ENGINE CONTROLS
DAEWOO M-150 BL2
DESCRIPTION AND OPERATION
IGNITION SYSTEM OPERATION
This ignition system does not use a conventional distrib-
utor and coil. It uses a crankshaft position sensor input
to the Engine Control Module (ECM). The ECM then de-
termines Electronic Spark Timing (EST) and triggers the
electronic ignition system ignition coil.
This type of distributorless ignition system uses a “waste
spark’’ method of spark distribution. Each cylinder is in-
dividural with coil per cylinder.
These systems use the EST signal from the ECM to
control the EST. The ECM uses the following informa-
tion:

Engine load (manifold pressure or vacuum).

Atmospheric (barometric) pressure.

Engine temperature.

Intake air temperature.

Crankshaft position.

Engine speed (rpm).
ELECTRONIC IGNITION SYSTEM
IGNITION COIL
The Electronic Ignition (EI) system ignition coil is
mounted near on the cylinder head.
A terminals of the EI system ignition coil provides the
spark for each spark plug. The EI system ignition coil is
not serviceable and must be replaced as an assembly.
CRANKSHAFT POSITION SENSOR
This Electronic Ignition (EI) system uses a magnetic
crankshaft position sensor. This sensor protrudes
through its mount to within approximately 1.3 mm (0.05
inch) of the crankshaft reluctor. The reluctor is a special
wheel attached to the crankshaft with 58 slots machined
into it, 57 of which are equally spaced in 6-degree inter-
vals. The last slot is wider and serves to generate a
“sync pulse.” As the crankshaft rotates, the slots in the
reluctor change the magnetic field of the sensor, creat-
ing an induced voltage pulse. The longer pulse of the
58th slot identifies a specific orientation of the crank-
shaft and allows the Engine Control Module (ECM) to
determine the crankshaft orientation at all times. The
ECM uses this information to generate timed ignition
and injection pulses that it sends to the ignition coils and
to the fuel injectors.
CAMSHAFT POSITION SENSOR
The Camshaft Position (CMP) sensor sends a CMP sig-
nal to the Engine Control Module (ECM). The ECM uses
this signal as a “sync pulse” to trigger the injectors in the
proper sequence. The ECM uses the CMP signal to indi-
cate the position of the #1 piston during its power stroke.
This allows the ECM to calculate true sequential fuel in-jection mode of operation. If the ECM detects an incor-
rect CMP signal while the engine is running, Diagnostic
Trouble Code (DTC) P0341 will set. If the CMP signal is
lost while the engine is running, the fuel injection system
will shift to a calculated sequential fuel injection mode
based on the last fuel injection pulse, and the engine will
continue to run. As long as the fault is present, the en-
gine can be restarted. It will run in the calculated se-
quential mode with a 1-in-6 chance of the injector
sequence being correct.
IDLE AIR SYSTEM OPERATION
The idle air system operation is controlled by the base
idle setting of the throttle body and the Idle Air Control
(IAC) valve.
The Engine Control Module (ECM) uses the IAC valve to
set the idle speed dependent on conditions. The ECM
uses information from various inputs, such as coolant
temperature, manifold vacuum, etc., for the effective
control of the idle speed.
FUEL CONTROL SYSTEM
OPERATION
The function of the fuel metering system is to deliver the
correct amount of fuel to the engine under all operating
conditions. The fuel is delivered to the engine by the in-
dividual fuel injectors mounted into the intake manifold
near each cylinder.
The main fuel control sensors are the Manifold Absolute
Pressure (MAP) sensor, the oxygen sensor (O2S), and
the heated oxygen sensor (HO2S).
The MAP sensor measures or senses the intake man-
ifold vacuum. Under high fuel demands, the MAP sensor
reads a low vacuum condition, such as wide open
throttle. The Engine Control Module (ECM) uses this in-
formation to enrich the mixture, thus increasing the fuel
injector on-time, to provide the correct amount of fuel.
When decelerating, the vacuum increases. This vacuum
change is sensed by the MAP sensor and read by the
ECM, which then decreases the fuel injector on-time
due to the low fuel demand conditions.
The O2S is located in the exhaust manifold. The HO2S
is located in the exhaust pipe. The oxygen sensors indi-
cate to the ECM the amount of oxygen in the exhaust
gas, and the ECM changes the air/fuel ratio to the en-
gine by controlling the fuel injectors. The best air/fuel ra-
tio to minimize exhaust emissions is 14.7:1, which
allows the catalytic converter to operate most efficiently.
Because of the constant measuring and adjusting of the
air/fuel ratio, the fuel injection system is called a “closed
loop” system.
The ECM uses voltage inputs from several sensors to
determine how much fuel to provide to the engine. The