1994 JEEP CHEROKEE spark plugs

MAINTENANCE SCHEDULES
INTRODUCTION
Chrysler Corporation has compiled recommended
lubrication and maintenance schedules and proce-
dures to help reduce premature wear or failure over
a broad range of operating conditions.
SEVERE SERVICE MAINTENANCE
If the vehicle is involved with a severe driving con-
dition, after each 4 800-km (3,000-miles)/3-month in-
terval. A severe driving condition includes:
²frequent short trip driving less than 24 km (15
miles);
²frequent driving in a dusty environment;
²trailer towing;
²extensive engine idling;
²sustained high-speed operation;
²desert operation;
²frequent starting and stopping;
²cold-climate operation;
²off-road driving; or
²commercial service.
MAINTENANCE SCHEDULES
AT EACH STOP FOR FUEL
²Check engine oil level, add as required.
²
Check windshield washer solvent and add if required.
ONCE A MONTH
²Check tire pressure and look for unusual wear or
damage.
²Inspect battery and clean and tighten terminals as
required.
²Check electrolyte level and add water as needed.
²Check fluid levels of coolant reservoir, power steer-
ing and transmission and add as needed.
²Check all lights and all other electrical items for
correct operation.
²Check rubber seals on each side of the radiator for
proper fit.
7,500 MILES (12 000 KM) OR AT 6 MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
15,000 MILES (24 000 KM) OR AT 12 MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.²Check fluid level in battery.
²Rotate Tires.
22,500 MILES (36 000 KM) OR AT 18 MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
30,000 MILES (48 000 KM) OR AT 24 MONTHS
²Replace air cleaner filter.
²Replace spark plugs.
²Adjust drive belt.
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Check fluid level in battery.
²Drain and refill automatic transmission.
²Drain and refill transfer case.
²Rotate Tires.
37,500 MILES (60 000 KM) OR AT 30 MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Drain and refill manual transmission.
²Rotate Tires.
45,000 MILES (72 500 KM) OR AT 36 MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Check fluid level in battery.
²Rotate Tires.
52,500 MILES (84 500 KM) OR AT 42 MONTHS
²Flush and replace engine coolant.
²Check engine coolant system hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
JLUBRICATION AND MAINTENANCE 0 - 5

60,000 MILES (96 500 KM) OR AT 48 MONTHS.
²Replace air cleaner filter.
²Replace distributor cap and rotor.
²Replace ignition wires.
²Replace spark plugs.
²Adjust or replace drive belt.
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Replace fuel filter (not required for Calif. vehicles).
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Check fluid level in battery.
²Drain and refill automatic transmission.
²Drain and refill transfer case.
²Rotate Tires.
67,500 MILES (108 500 KM) OR AT 54
MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
75,000 MILES (120 500 KM) OR AT 60
MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Drain and refill manual transmission.
²Rotate Tires.
82,500 MILES (133 000 KM) OR AT 66
MONTHS
²Flush and replace engine coolant.
²Check engine coolant system, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
90,000 MILES (145 000 KM) OR AT 72
MONTHS
²Replace air cleaner filter.
²Replace spark plugs.
²Adjust drive belt.
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Check fluid level in battery.
²Drain and refill automatic transmission.
²Drain and refill transfer case.
²Rotate Tires.
97,500 MILES (157 000 KM) OR AT 78
MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
105,000 MILES (169 000 KM) OR AT 84
MONTHS
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
112,500 MILES (181 000 KM) OR AT 90
MONTHS
²Flush and replace engine coolant.
²Check engine coolant system hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Rotate Tires.
120,000 MILES (193 000 KM) OR AT 96
MONTHS
²Replace air cleaner filter.
²Replace distributor cap and rotor.
²Replace ignition wires.
²Replace spark plugs.
²Adjust or replace drive belt.
²Check engine coolant level, hoses and clamps.
²Change engine oil.
²Replace engine oil filter.
²Check exhaust system.
²Replace fuel filter (not required for Calif. vehicles).
²Lubricate steering linkage (4x4 models).
²Lubricate propeller shaft universal joints.
²Check fluid level in battery.
²Drain and refill automatic transmission.
²Drain and refill transfer case.
²Rotate Tires.
0 - 6 LUBRICATION AND MAINTENANCEJ

ENGINE MAINTENANCE
INDEX
page page
Accessory Drive Belt...................... 20
Air-Conditioner Compressor/Hoses/Fittings...... 21
Battery................................ 18
Cooling System.......................... 16
Crankcase Ventilation System............... 17
Engine Air Cleaner Filter Element............ 16
Engine Break-In......................... 13
Engine Oil.............................. 13Engine Oil Change and Filter Replacement..... 15
Engine Oil Filter......................... 14
Engine Supports......................... 20
Exhaust System......................... 20
Fuel Usage StatementÐGas Engines......... 17
Ignition Cables, Distributor Cap and Rotor...... 18
Rubber and Plastic Ducts/Hoses/Tubing....... 19
Spark Plugs............................ 18
ENGINE BREAK-IN
After first starting a new engine, allow it to idle
and warm up for at least 15 seconds before shifting
the transmission into a drive gear.
Drive the vehicle at:
²varying speeds less than 80 km/h (50 mph) for the
first 160 km (100 miles), and
²speeds less than 88 km/h (55 mph) for the first 800
km (500 miles).
Avoid driving at full-throttle for extended periods
of time. Also, avoid fast acceleration and sudden
stops.
A special break-in engine oil is not required. The
original oil installed in a vehicle is a quality lubri-
cant. There is no requirement to have the oil
changed or the oil filter replaced until the first
scheduled maintenance interval.
The engine oil, coolant and all the other engine re-
lated fluid levels should be determined on a regular
basis.
ENGINE OIL
SPECIFICATIONS
API SERVICE GRADE
For maximum engine protection during all driving
conditions, install an engine oil that conforms to API
Service Grade. MOPAR Engine Oil conforms to all of
these API Service Grades.
SAE VISCOSITY
SAE designated multi-viscosity grade engine oil is
to protect engines. This type of engine oil can usually
be installed and remain in the engine until the next
scheduled oil change. Select the engine oil viscosity
according to the lowest ambient air temperature ex-
pected before the next scheduled oil change (Fig.1).
Low viscosity engine oil allows easier engine starting
during cold weather. SAE 5W-30 viscosity engine oil
is recommended when the ambient air temperatures
consistently decrease to below 10ÉF (-12ÉC).ENERGY CONSERVING OIL
In selecting the correct API grade and SAE grade,
anENERGY CONSERVINGtype engine oil is also
recommended.
CONTAINER IDENTIFICATION
Standard engine oil notations have been adopted
for selection of engine oil. The notations are located
on side of plastic bottles and on the top of engine oil
cans (Fig. 2).
²The top, outer field contains theAPI Service
Gradenotation for the engine oil.
Fig. 1 Temperature/Engine Oil Viscosity
Fig. 2 Engine Oil Container Standard Notations
JLUBRICATION AND MAINTENANCE 0 - 13

In areas of the country where carbon monoxide lev-
els are high, gasolines are being treated with oxy-
genated materials such as MTBE, ETBE and
ethanol.
Chrysler Corporation supports these efforts toward
cleaner air and recommends the use of these gaso-
lines as they become available.
IGNITION CABLES, DISTRIBUTOR CAP AND
ROTOR
REQUIRED IGNITION SYSTEM MAINTENANCE
The ignition cables, distributor cap and rotor must
be replaced after each 96 000-km (60,000-miles). Re-
fer to Group 8DÐIgnition Systems for additional in-
formation.
IGNITION TIMING
The ignition timing for 2.5L and 4.0L engines is
not adjustable. Refer to the specifications listed on
the engine Emission Control Information Label. Re-
fer to Group 25ÐEmission Control Systems for addi-
tional information.
SPARK PLUGS
REQUIRED MAINTENANCE
The spark plugs must be replaced after each 48
000-km (30,000-miles). Refer to the Spark Plugs
chart below and to Group 8DÐIgnition Systems for
additional information.
BATTERY
RECOMMENDED MAINTENANCE
The battery electrolyte level should be checked and
the cable clamps should be inspected for corrosion.
This should be done when the oil is changed and the
oil filter is replaced.
The battery cables should be inspected for abnor-
mal clamp and battery terminal post corrosion. Ser-
vice the terminals and cable clamps as necessary.In addition, the general condition of the battery
should be determined before the start of cold and hot
weather seasons. If the battery condition is marginal
or worse, it should be replaced.
Care should be taken when disposing a bat-
tery after removal from a vehicle. Lead-acid bat-
teries are highly poisonous and, when
indiscriminately disposed, could create a prob-
lem for the environment. Contact the applicable
local city or county government agency to deter-
mine where automobile (lead-acid) batteries can
be properly disposed in the local area.
INSPECTION/SERVICE
WARNING: WEAR SAFETY GLASSES, RUBBER
GLOVES AND PROTECTIVE CLOTHING WHEN HAN-
DLING/SERVICING A BATTERY. THE BATTERY
ELECTROLYTE CONTAINS SULFURIC ACID AND
WILL CAUSE HARM IF IT CONTACTS SKIN, EYES
OR CLOTHING. IT WILL ALSO DAMAGE PAINTED
(AS WELL AS UN-PAINTED) SURFACES OF A VEHI-
CLE. IF SULFURIC ACID CONTACTS ANY OF
THESE, FLUSH IMMEDIATELY WITH LARGE
AMOUNTS OF WATER. IF SULFURIC ACID CON-
TACTS SKIN OR EYES, GET IMMEDIATE MEDICAL
ATTENTION. DO NOT SMOKE IN THE VICINITY OF
A BATTERY. KEEP OPEN FLAMES AND SPARKS
AWAY FROM BATTERY FILLER CAPS BECAUSE
EXPLOSIVE GAS IS ALWAYS PRESENT.
(1) Disconnect the battery negative cable and then
the positive cable.
(2) Clean the battery cable clamps and terminal
posts with a wire brush and a battery terminal
cleaner.
(3) Pry the battery cell filler caps upward to re-
move them and inspect each filler well (low-mainte-
nance batteries only, not applicable to maintenance-
free batteries). It could possibly be necessary to
loosen the battery holddown clamp to remove the
caps. Maintain the electrolyte level above the battery
plates and at the bottom of the filler well ring. Add
distilled water or low-mineral content drinking wa-
ter, if necessary. In freezing weather (below 0ÉC/
32ÉF), add the water just before driving to ensure
that it mixes thoroughly with the electrolyte. This
will prevent it from freezing.
(4) Remove the battery holddown strap and clean
the battery case/battery tray.Clean with bicarbonate
of soda (baking soda) and water. Rinse and dry the
battery case/tray thoroughly after cleaning.
(5) Position the battery in the tray and install the
holddown strap.Do not over-tighten the nuts.
(6) Connect the battery positive cable and then the
negative cable to the battery.
SPARK PLUGS
0 - 18 LUBRICATION AND MAINTENANCEJ

(4) Inspect ignition coil connections. Verify that
coil secondary cable is firmly connected to coil (Figs.
5or6).(5) Verify that distributor cap is correctly attached
to distributor. Be sure that spark plug cables are
firmly connected to the distributor cap and the spark
plugs in their correct firing order. Be sure that coil
cable is firmly connected to distributor cap and coil.
Be sure that camshaft position sensor wire connector
is firmly connected to harness connector (Figs. 7 or
8). Inspect spark plug condition. Refer to Group 8D,
Ignition System. Connect vehicle to an oscilloscope
and inspect spark events for fouled or damaged spark
plugs or cables.
(6) Verify that generator output wire, generator
connector and ground wire are firmly connected to
the generator (Fig. 9).
(7) Inspect the system ground connections at the
cylinder block behind the engine oil dipstick tube
(Fig. 10).
Fig. 4 PDCÐXJ Models
Fig. 5 Ignition CoilÐ2.5L Engine
Fig. 6 Ignition CoilÐ4.0L Engine
Fig. 7 Distributor and WiringÐ2.5L Engine
Fig. 8 Distributor and WiringÐ4.0L Engine
JFUEL SYSTEM 14 - 33

87 and 30. Continuity should not be present between
terminals number 87A and 30.
(8) Disconnect jumper wires from relay and 12
Volt power source.
If continuity or resistance tests did not pass, re-
place relay. If tests passed, refer to Group 8W, Wir-
ing Diagrams for additional circuit information. Also
refer to the appropriate Powertrain Diagnostic Proce-
dures manual for operation of the DRB scan tool.
STARTER MOTOR RELAY TEST
Refer to Group 8A, Battery/Starting/Charging/Sys-
tem Diagnostics, for starter motor relay testing.
INJECTOR TEST
Disconnect the injector wire connector from the in-
jector. Place an ohmmeter on the injector terminals.
Resistance reading should be approximately 14.5
ohms61.2 ohms at 20ÉC (68ÉF). Proceed to following
Injector Diagnosis chart.
FUEL SYSTEM PRESSURE TEST
Refer to the Fuel Delivery System section of this
group. See Fuel System Pressure Test.
ON-BOARD DIAGNOSTICS (OBD)
The Powertrain Control Module (PCM) has been
programmed to monitor many different circuits of the
fuel injection system. If a problem is sensed in a
monitored circuit often enough to indicate an actual
problem, a Diagnostic Trouble Code (DTC) is stored.
The DTC will be stored in the PCM memory for
eventual display to the service technician. If the
problem is repaired or ceases to exist, the PCM can-
cels the DTC after 51 engine starts.
Certain criteria must be met for a diagnostic trou-
ble code (DTC) to be entered into PCM memory. The
criteria may be a specific range of engine rpm, en-
gine temperature and/or input voltage to the PCM.
It is possible that a DTC for a monitored circuit
may not be entered into memory even though a mal-
function has occurred. This may happen because one
of the DTC criteria for the circuit has not been met.
Example: assume that one of the criteria for the
MAP sensor circuit is that the engine must be oper-
ating between 750 and 2000 rpm to be monitored for
a DTC. If the MAP sensor output circuit shorts to
ground when the engine rpm is above 2400 rpm, a 0
volt input will be seen by the PCM. A DTC will not
be entered into memory because the condition does
not occur within the specified rpm range.
A DTC indicates that the powertrain control mod-
ule (PCM) has recognized an abnormal signal in a
circuit or the system. A DTC may indicate the result
of a failure, but never identify the failed component
directly.There are several operating conditions that the
PCM does not monitor and set a DTC for. Refer to
the following Monitored Circuits and Non-Monitored
Circuits in this section.
MONITORED CIRCUITS
The powertrain control module (PCM) can detect
certain problems in the fuel injection system.
Open or Shorted Circuit- The PCM can deter-
mine if sensor output (which is the input to PCM) is
within proper range. It also determines if the circuit
is open or shorted.
Output Device Current Flow- The PCM senses
whether the output devices are hooked up.
If there is a problem with the circuit, the PCM
senses whether the circuit is open, shorted to ground
(-), or shorted to (+) voltage.
Oxygen Sensor- The PCM can determine if the
oxygen sensor is switching between rich and lean.
This is, once the system has entered Closed Loop. Re-
fer to Open Loop/Closed Loop Modes Of Operation in
the Component Description/System Operation section
for an explanation of Closed (or Open) Loop opera-
tion.
NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems or conditions that could have malfunctions
that result in driveability problems. A Diagnostic
Trouble Code (DTC) may not be displayed for these
conditions.
Fuel Pressure: Fuel pressure is controlled by the
vacuum assisted fuel pressure regulator. The PCM
cannot detect a clogged fuel pump inlet filter, clogged
in-line fuel filter, or a pinched fuel supply or return
line. However, these could result in a rich or lean
condition causing an oxygen sensor DTC to be stored
in the PCM.
Secondary Ignition Circuit: The PCM cannot
detect an inoperative ignition coil, fouled or worn
spark plugs, ignition cross firing, or open circuited
spark plug cables.
Engine Timing: The PCM cannot detect an incor-
rectly indexed timing chain, camshaft sprocket or
crankshaft sprocket. The PCM also cannot detect an
incorrectly indexed distributor. However, these could
result in a rich or lean condition causing an oxygen
sensor DTC to be stored in the PCM.
Cylinder Compression: The PCM cannot detect
uneven, low, or high engine cylinder compression.
Exhaust System: The PCM cannot detect a
plugged, restricted or leaking exhaust system.
Fuel Injector Malfunctions: The PCM cannot de-
termine if the fuel injector is clogged, or the wrong
injector is installed. However, these could result in a
rich or lean condition causing an oxygen sensor DTC
to be stored in the PCM.
14 - 48 FUEL SYSTEMJ

Leakage Test. Do this if it is certain that coolant is
being lost and no leaks can be detected.
²Drops Slowly: Shows a small leak or seepage is oc-
curring. Examine all connections for seepage or
slight leakage with a flashlight. Inspect the radiator,
hoses, gasket edges and heater. Seal any small leak
holes with a Sealer Lubricant or equivalent. Repair
leak holes and reinspect the system with pressure
applied.
²Drops Quickly: Shows that a serious leakage is oc-
curring. Examine the system for serious external
leakage. If no leaks are visible, inspect for internal
leakage. Large radiator leak holes should be repaired
by a reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove the oil pan drain plug and drain a small
amount of engine oil. Coolant, being heavier will
drain first, or operate engine to churn oil, then ex-
amine dipstick for water globules. Inspect the trans-
mission dipstick for water globules. Inspect the
transmission fluid cooler for leakage. Operate the en-
gine without the pressure cap on the radiator until
thermostat opens.
Attach a Pressure Tester to the filler neck. If pres-
sure builds up quickly, a leak exists as result of a
faulty cylinder head gasket or crack in the engine.
Repair as necessary.
WARNING: DO NOT ALLOW PRESSURE TO EX-
CEED 124 KPA (18 PSI). TURN THE ENGINE OFF.
TO RELEASE THE PRESSURE, ROCK THE TESTER
FROM SIDE TO SIDE. WHEN REMOVING THE
TESTER, DO NOT TURN THE TESTER MORE THAN
1/2 TURN IF THE SYSTEM IS UNDER PRESSURE.
If there is no immediate pressure increase, pump
the Pressure Tester until the indicated pressure is
within the system range. Vibration of the gauge
pointer indicates compression or combustion leakage
into the cooling system.WARNING: DO NOT DISCONNECT THE SPARK
PLUG WIRES WHILE THE ENGINE IS OPERATING.
CAUTION: Do not operate the engine with a spark
plug shorted for more than a minute. The catalytic
converter may be damaged.
Isolate the compression leak by shorting each
spark plug to the cylinder block. The gauge pointer
should stop or decrease vibration when spark plug
for leaking cylinder is shorted. This happens because
of the absence of combustion pressure.
COMBUSTION LEAKAGE TEST (WITHOUT
PRESSURE TESTER)
DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
Drain sufficient coolant to allow for thermostat re-
moval. Refer to Thermostat Replacement. Disconnect
the water pump drive belt.
Disconnect the upper radiator hose from the ther-
mostat housing. Remove the housing and thermostat.
Install the thermostat housing.
Add coolant to the radiator to bring the level to
within 6.3 mm (1/4 in) of the top of the thermostat
housing.
CAUTION: Avoid overheating. Do not operate the
engine for an excessive period of time. Open the
draincock immediately after the test to eliminate
boil over of coolant.
Start the engine and accelerate rapidly three times
(to approximately 3000 rpm) while observing the
coolant. If internal engine combustion gases are leak-
ing into the cooling system, bubbles will appear in
the coolant. If bubbles do not appear, there is no in-
ternal combustion gas leakage.
COOLANT RESERVE/OVERFLOW SYSTEM
The system works along with the radiator pressure
cap. This is done by using thermal expansion and
contraction of the coolant to keep the coolant free of
trapped air. It provides:
²A volume for coolant expansion and contraction.
²A convenient and safe method for checking/adjust-
ing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
²Some reserve coolant to cover minor leaks and
evaporation or boiling losses.
Fig. 20 Pressurizing SystemÐTypical
JCOOLING SYSTEM 7 - 19

IGNITION SYSTEMS
CONTENTS
page page
COMPONENT IDENTIFICATION/SYSTEM
OPERATION.......................... 1
COMPONENT REMOVAL/INSTALLATION..... 20DIAGNOSTICS/SERVICE PROCEDURES....... 8
IGNITION SWITCH...................... 30
SPECIFICATIONS....................... 33
COMPONENT IDENTIFICATION/SYSTEM OPERATION
INDEX
page page
Automatic Shut Down (ASD) Relay............ 1
Camshaft Position Sensor................... 1
Crankshaft Position Sensor.................. 2
Distributors.............................. 3
Engine Coolant Temperature Sensor........... 4
General Information........................ 1Ignition Coil.............................. 4
Intake Manifold Air Temperature Sensor........ 5
Manifold Absolute Pressure (MAP) Sensor...... 5
Powertrain Control Module (PCM)............. 6
Throttle Position Sensor.................... 6
GENERAL INFORMATION
Throughout this group, references are made to par-
ticular vehicle models by alphabetical designation
(XJ or YJ) or by the particular vehicle nameplate. A
chart showing a breakdown of alphabetical designa-
tions is included in the Introduction group at the be-
ginning of this manual.
This section of the group, Component Identifica-
tion/System Operation, will discuss ignition system
operation and will identify ignition system compo-
nents.
For diagnostic procedures and adjustments, refer to
the Diagnostics/Service Procedures section of this
group.
For removal and installation of ignition system
components, refer to the Component Removal/Instal-
lation section of this group.
For other useful information, refer to On-Board Di-
agnostics in the General Diagnosis sections of Group
14, Fuel System in this manual.
For operation of the DRB Scan Tool, refer to the
appropriate Powertrain Diagnostic Procedures ser-
vice manual.
An Ignition specifications section is included at the
end of this group. A general Maintenance Schedule
(mileage intervals) for ignition related items can be
found in Group 0, Lubrication and Maintenance. This
schedule can also be found in the Owners Manual.
IGNITION SYSTEMS
A multi-port, fuel injected engine is used on all
models. The ignition system is controlled by the Pow-
ertrain Control Module (PCM) on all engines. The
PCM was formerly referred to as the SBEC or engine
controller.
The ignition system consists of:
²Spark Plugs
²Ignition Coil
²Secondary Ignition Cables
²Ignition distributor (contains rotor and camshaft
position sensor)
²Powertrain Control Module (PCM)
²Crankshaft Position Sensor
AUTOMATIC SHUT DOWN (ASD) RELAY
The automatic shut down (ASD) relay is located in
the Power Distribution Center (PDC) near the bat-
tery (Fig. 1 or 2). As one of its functions, it will sup-
ply battery voltage to the ignition coil. The ground
circuit for the ASD relay is controlled by the Power-
train Control Module (PCM). The PCM regulates
ASD relay operation by switching the ground circuit
on-and-off.
CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the igni-
tion distributor (Figs. 3 or 4) on all engines.
The camshaft position sensor contains a hall effect
device called a sync signal generator to generate a
fuel sync signal. This sync signal generator detects a
JIGNITION SYSTEMS 8D - 1