IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION - IGNITION SYSTEM..........1
OPERATION - IGNITION SYSTEM...........1
SPECIFICATIONS
TORQUE.............................2
SPARK PLUG CABLE RESISTANCE........2
SPARK PLUG.........................2
FIRING ORDER........................3
AUTO SHUT DOWN RELAY
DESCRIPTION..........................3
OPERATION............................3
CAMSHAFT POSITION SENSOR
DESCRIPTION..........................4
OPERATION............................4
REMOVAL
REMOVAL - 2.4L.......................5
REMOVAL - 3.3/3.8L....................5
INSTALLATION
INSTALLATION - 2.4L...................6
INSTALLATION - 3.3/3.8L.................6
IGNITION COIL
DESCRIPTION..........................6
OPERATION............................6
REMOVAL
REMOVAL - 2.4L.......................7REMOVAL - 3.3/3.8L....................7
INSTALLATION
INSTALLATION - 2.4L...................7
INSTALLATION - 3.3/3.8L.................8
KNOCK SENSOR
DESCRIPTION..........................8
OPERATION............................8
REMOVAL
REMOVAL - 2.4L.......................8
REMOVAL - 3.8L.......................8
INSTALLATION
INSTALLATION - 2.4L...................8
INSTALLATION - 3.8L...................8
SPARK PLUG
DESCRIPTION
DESCRIPTION - STANDARD 4 CYLINDER . . . 9
DESCRIPTION - PLATINUM PLUGS........9
REMOVAL.............................10
INSTALLATION.........................10
SPARK PLUG CABLE
DESCRIPTION.........................10
REMOVAL - 2.0/2.4L.....................10
INSTALLATION - 2.0/2.4L.................10
IGNITION CONTROL
DESCRIPTION - IGNITION SYSTEM
NOTE: All engines use a fixed ignition timing sys-
tem. Basic ignition timing is not adjustable. All
spark advance is determined by the Powertrain
Control Module (PCM).
The ignition system used on these engines is
referred to as the Direct Ignition System (DIS). The
system's three main components are the coils, crank-
shaft position sensor, and camshaft position sensor. If
equipped with the coil on plug ignition system it uti-
lizes an ignition coil for every cylinder, it is mounted
directly over the each spark plug.
OPERATION - IGNITION SYSTEM
The crankshaft position sensor and camshaft posi-
tion sensor are hall effect devices. The camshaft posi-
tion sensor and crankshaft position sensor generate
pulses that are inputs to the PCM. The PCM deter-
mines engine position from these sensors. The PCM
calculates injector sequence and ignition timing from
crankshaft & camshaft position. For a description of
both sensors, refer to Camshaft Position Sensor and
Crankshaft Position Sensor.
RSIGNITION CONTROL8I-1
FIRING ORDERAUTO SHUT DOWN RELAY
DESCRIPTION
The relay is located in the Power Distribution Cen-
ter (PDC). For the location of the relay within the
PDC, refer to the PDC cover for location. Check elec-
trical terminals for corrosion and repair as necessary
OPERATION
The engine switched battery (NGC vehicles)
informs the PCM when the ASD relay energizes. A 12
volt signal at this input indicates to the PCM that
the ASD has been activated. This input is also used
to power certain drivers on NGC vehicles.
When energized, the ASD relay on NGC vehicles
provides power to operate the injectors, ignition coil,
generator field, O2 sensor heaters (both upstream
and downstream), evaporative purge solenoid, EGR
solenoid (if equipped) wastegate solenoid (if
equipped), and NVLD solenoid (if equipped).
The ASD relay also provides a sense circuit to the
PCM for diagnostic purposes. If the PCM does not
receive 12 volts from this input after grounding the
control side of the ASD relay, it sets a Diagnostic
Trouble Code (DTC). The PCM energizes the ASD
any time there is an engine speed that exceeds a pre-
determined value (typically about 50 rpm). The ASD
relay can also be energized after the engine has been
turned off to perform an O2 sensor heater test, if
vehicle is equipped with OBD II diagnostics.
As mentioned earlier, the PCM energizes the ASD
relay during an O2 sensor heater test. On NGC vehi-
cles it checks the O2 heater upon vehicle start. The
PCM still operates internally to perform several
checks, including monitoring the O2 sensor heaters.
FIRING ORDER 2.4L
Firing Order 1-2-3-4-5-6 3.3/3.8L
1 - Electrical Connector
RSIGNITION CONTROL8I-3
IGNITION CONTROL (Continued)
REMOVAL
REMOVAL - 2.4L
The camshaft position sensor is mounted to the
rear of the cylinder head.
(1) Remove the negative battery cable.
(2) Disconnect electrical connectors from the cam-
shaft position sensor (Fig. 3).
(3) Remove camshaft position sensor mounting
screws. Remove sensor.
(4) Loosen screw attaching target magnet to rear
of camshaft and remove magnet (Fig. 4).
REMOVAL - 3.3/3.8L
(1) Disconnect the negative battery cable.
(2) Remove the air box cover and inlet tube (Fig.
5).
(3) Disconnect camshaft position sensor electrical
connector from the wiring harness connector (Fig. 6).
(4) Remove bolt holding sensor.
(5) Rotate sensor away from block.
Fig. 3 EGR/CAM SENSOR 2.4L
Fig. 4 Target Magnet Removal/Installation
1 - TARGET MAGNET
2 - MOUNTING BOLT
3 - REAR OF CYLINDER HEAD
Fig. 5 AIR BOX COVER
Fig. 6 CAMSHAFT POSITION SENSOR
RSIGNITION CONTROL8I-5
CAMSHAFT POSITION SENSOR (Continued)
INSTALLATION - 3.3/3.8L
(1) Install coil over studs on bracket.
(2) Install 2 nuts to the ignition coil studs. Tighten
nuts and bolts.
(3) Connect the electrical connector to the ignition
coil.
(4) Install the ignition cables to the ignition coil.
(5) Reposition the Power steering reservoir. Slide
bracket over the mounting stud (Fig. 11).
(6) Install 2 bolts to the Power steering reservoir
to intake manifold.
(7) Tighten the lower nut to stud on ignition coil
bracket.
(8) Install the throttle and speed control cables to
clip.
(9) Connect the negative battery cable.
KNOCK SENSOR
DESCRIPTION
The knock sensor threads into the cylinder block.
The knock sensor is designed to detect engine vibra-
tion that is caused by detonation.
OPERATION
When the knock sensor detects a knock in one of
the cylinders, it sends an input signal to the PCM. In
response, the PCM retards ignition timing for all cyl-
inders by a scheduled amount.
Knock sensors contain a piezoelectric material
which constantly vibrates and sends an input voltage
(signal) to the PCM while the engine operates. As the
intensity of the crystal's vibration increases, the
knock sensor output voltage also increases.
The voltage signal produced by the knock sensor
increases with the amplitude of vibration. The PCM
receives as an input the knock sensor voltage signal.
If the signal rises above a predetermined level, the
PCM will store that value in memory and retard
ignition timing to reduce engine knock. If the knock
sensor voltage exceeds a preset value, the PCM
retards ignition timing for all cylinders. It is not a
selective cylinder retard.
The PCM ignores knock sensor input during engine
idle conditions. Once the engine speed exceeds a
specified value, knock retard is allowed.
Knock retard uses its own short term and long
term memory program.
Long term memory stores previous detonation
information in its battery-backed RAM. The maxi-
mum authority that long term memory has over tim-
ing retard can be calibrated.
Short term memory is allowed to retard timing up
to a preset amount under all operating conditions (as
long as rpm is above the minimum rpm) except WOT.The PCM, using short term memory, can respond
quickly to retard timing when engine knock is
detected. Short term memory is lost any time the
ignition key is turned off.
NOTE: Over or under tightening affects knock sen-
sor performance, possibly causing improper spark
control.
REMOVAL
REMOVAL - 2.4L
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 12).
(1) Disconnect electrical connector from knock sen-
sor.
(2) Use a crow foot socket to remove the knock
sensors.
REMOVAL - 3.8L
The knock sensor threads into the side of the cyl-
inder block in the rear.
(1) Disconnect the negative battery cable.
(2) Raise vehicle and support.
(3) On All Wheel Drive vehicles remove the PTU
(Power Transfer Unit), refer to the Transmission sec-
tion for more information.
(4) Disconnect electrical connector from knock sen-
sor.
(5) Use a crow foot socket to remove the knock
sensor.
INSTALLATION
INSTALLATION - 2.4L
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 12).
(1) Install knock sensor. Tighten knock sensor to
10 N´m (7 ft. lbs.) torque.Over or under tighten-
ing effects knock sensor performance, possibly
causing improper spark control.
(2) Attach electrical connector to knock sensor.
INSTALLATION - 3.8L
The knock sensor threads into the side of the cyl-
inder block in the rear.
(1) Install knock sensor. Tighten knock sensor to
10 N´m (7 ft. lbs.) torque.Over or under tighten-
ing effects knock sensor performance, possibly
causing improper spark control.
(2) Attach electrical connector to knock sensor.
(3) On All Wheel Drive vehicles install the PTU
(Power Transfer Unit) for the rear wheels, refer to
the Transmission section for more information.
8I - 8 IGNITION CONTROLRS
IGNITION COIL (Continued)
REMOVAL
When replacing the spark plugs and spark plug
cables, route the cables correctly and secure them in
the appropriate retainers. Failure to route the cables
properly can cause the radio to reproduce ignition
noise, cross ignition of the spark plugs orshort cir-
cuit the cables to ground.
Always remove cables by grasping at the boot,
rotating the boot 1/2 turn, and pulling straight back
in a steady motion.
(1) Prior to removing the spark plug, spray com-
pressed air around the spark plug hole and the area
around the spark plug.
(2) Remove the spark plug using a quality socket
with a foam insert.
(3) Inspect the spark plug condition.
INSTALLATION
When replacing the spark plugs and spark plug
cables, route the cables correctly and secure them in
the appropriate retainers. Failure to route the cables
properly can cause the radio to reproduce ignition
noise, cross ignition of the spark plugs orshort cir-
cuit the cables to ground.
(1) Coat threads of spark plug with anti-seize. Be
sure not to get anti-seizeANYWHERE BUT ON
THE THREADS OF THE SPARK PLUG as
shown in (Fig. 13).
(2) To avoid cross threading, start the spark plug
into the cylinder head by hand.
(3) Tighten spark plugs to 17.5 N´m (13 ft. lbs.)
torque.
(4) Install spark plug cables over spark plugs. A
click will be heard and felt when the cable properly
attaches to the spark plug.
SPARK PLUG CABLE
DESCRIPTION
Spark Plug cables are sometimes referred to as
secondary ignition wires. The wires transfer electri-
cal current from the ignition coil pack to individualspark plugs at each cylinder. The resistive spark plug
cables are of nonmetallic construction. The cables
provide suppression of radio frequency emissions
from the ignition system.
Check the spark plug cable connections for good
contact at the coil, and spark plugs. Terminals should
be fully seated. The insulators should be in good con-
dition and should fit tightly on the coil, and spark
plugs. Spark plug cables with insulators that are
cracked or torn must be replaced.
Clean Spark Plug cables with a cloth moistened
with a non-flammable solvent. Wipe the cables dry.
Check for brittle or cracked insulation. The spark
plug cables and spark plug boots are made from high
temperature materials.
REMOVAL - 2.0/2.4L
Failure to route the cables properly could cause the
radio to reproduce ignition noise, cross ignition of the
spark plugs or short circuit the cables to ground.
Remove spark plug cable from coil first.
Always remove the spark plug cable by grasping
the top of the spark plug insulator, turning the boot
1/2 turn and pulling straight up in a steady motion.
INSTALLATION - 2.0/2.4L
Failure to route the cables properly could cause the
radio to reproduce ignition noise, cross ignition of the
spark plugs or short circuit the cables to ground.
Install spark plug insulators over spark plugs.
Ensure the top of the spark plug insulator covers the
upper end of the spark plug tube, then connect the
other end to coil pack.
8I - 10 IGNITION CONTROLRS
SPARK PLUG (Continued)
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - SELF-
DIAGNOSTICS
The instrument clusters are equipped with a self
diagnostic test feature to help identify electronic
problems. Prior to any test, perform the Self-Diag-
nostic Test. The self diagnostic system displays
instrument cluster stored fault codes in the odometer
display, sweeps the gauges to the calibration points,
and bulb checks the warning indicators. When the
key is in the ON position with the engine not run-
ning, the MIL will remain illuminated for regulatory
purposes.
To activate the Self-Diagnostic program:
(1) With the ignition switch in the OFF position,
depress the TRIP ODOMETER RESET button.
(2) Continue to hold the TRIP ODOMETER
RESET button untilSofand a number (software ver-
sion number (i.e.Sof 3.2) appears in the odometer
window then release the button. If a fault code is
present, the cluster will display it in the odometer
display. When all fault codes have been displayed,
the cluster will displayªendºin the odometer dis-
play. Refer to the INSTRUMENT CLUSTER DTC'S
table to determine what each trouble code means.
INSTRUMENT CLUSTER DTC'S
DTC DESCRIPTION
100.0 LOOP-BACK FAILURE
100.1 ABS COMMUNICATION FAULT
100.2 BCM COMMUNICATION FAULT
100.3 EATX COMMUNICATION FAULT
100.4 FCM COMMUNICATION FAULT
100.5 ORC COMMUNICATION FAULT
100.6SBEC/DEC/MCM COMMUNICATION
FAULT
200.0 AIRBAG LED SHORT
200.1 AIRBAG LED OPEN
200.2 ABS LED SHORT
200.3 ABS LED OPEN
200.6 EL INVERTER TIME-OUT
200.7 EATX MISMATCH
400.0 EEPROM READ/WRITE FAILURE
400.1IMPROPER POWER DOWN
DETECTED
CALIBRATION TEST
The CLUSTER CALIBRATION table contains the
proper calibration points for each gauge. If the gauge
pointers are not calibrated, a problem exists in the
cluster. If any gauge is out of calibration, replace the
cluster.
CLUSTER CALIBRATION
SPEEDOMETER CALIBRATION POINT
1 0 MPH (0 KM/H)
2 20 MPH (40 KM/H)
3 60 MPH (100 KM/H)
4 100 MPH (160 KM/H)
TACHOMETER
1 0 RPM
2 1000 RPM
3 3000 RPM
4 6000 RPM
FUEL GAUGE
1 EMPTY
2 1/4 FILLED
3 1/2 FILLED
4 FULL
TEMPERATURE
GAUGE
1 COLD
2 1/4
3 3/4
4 HOT
ODOMETER SEGMENT TEST
If a segment in the odometer does not illuminate
normally, a problem exists in the display.
ELECTRONIC TRANSMISSION RANGE INDICATOR
SEGMENT TEST
If a segment in the transmission range indicator
does not illuminate normally, a problem exists in the
display.
8J - 2 INSTRUMENT CLUSTERRS
INSTRUMENT CLUSTER (Continued)
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION
LAMP SYSTEMS
Lighting circuits are protected by fuses. Lighting
circuits require an overload protected power and high
side drivers source, ON/OFF device, lamps and body
grounds to operate properly. Plastic lamps require a
wire in the harness to supply body ground to the
lamp socket. Replace sockets and bulbs that are cor-
roded.
Some of the interior and exterior lighting functions
are governed by the Body Control Module (BCM).
The headlamp, dome, and the door ajar switches pro-
vide signals to the BCM. The BCM in turn sends a
Programmable Communication Interface (PCI) bus
message to the Front Control Module (FCM) to
enable the necessary drivers to set the required illu-
mination configuration.
Wire connectors can make intermittent contact or
become corroded. Before coupling wire connectors,
inspect the terminals inside the connector. Male ter-
minals should not be bent or disengaged from the
insulator. Female terminals should not be sprung
open or disengaged from the insulator. Bent and
sprung terminals can be repaired using needle nose
pliers and pick tool. Corroded terminals appear
chalky or green. Corroded terminals should be
replaced to avoid recurrence of the problem symp-
toms.
Begin electrical system failure diagnosis by testing
related fuses in the fuse block and intelligent power
module. Verify that bulbs are in good condition and
test continuity of the circuit ground. Refer to the
appropriate wiring information.
AUTOMATIC HEADLAMP SYSTEM
The Automatic Headlamp system turns the instru-
mentation and exterior illumination lamps ON when
the ambient light levels are Night and the engine
RPM is 450 or above, and OFF when light levels are
Day.
DAYTIME RUNNING LAMPS
Operating the high-beam headlamps at reduced
power provides daytime running lamps, which are
required on all new Canadian vehicles. Daytime run-
ning lamps are functional when 450 rpm's are
reached.
HEADLAMPS ON WITH WINDSHIELD WIPERS
For vehicles equipped with the Automatic Head-
lamp System, the instrumentation and exterior illu-
mination lamps will be turned ON when the
headlamp switch is in the AUTO position, RPM >450 and the windshield wipers have been in the
intermittent, low or high mode of operation for more
than ten seconds. When the windshield wipers are
turned OFF the Body Control Module will determine
if the instrumentation and exterior illumination
lamps should remain ON base upon the current
ambient light level.
HEADLAMP SYSTEM
The configuration of the headlamp system of head-
lamps, park lamps and fog lamps is determined by
the BCM. The BCM determines the lighting configu-
ration as a result of the inputs from the ignition
switch, headlamp switch and multi-function switch. A
PCI bus is transmitted from the BCM to the FCM to
enable the necessary drivers to set the illumination
configuration. Four wires are connected between the
headlamp switch and the BCM. The first wire con-
tains information regarding the position of the head-
lamp switch (Off, Automatic Headlamps, Automatic
Headlamp switch fog, Park with Fog, Head, or Head
with Fog Lamps). The second wire contains informa-
tion regarding the position of the dimmer switch
(Dome Lamp, Daytime Brightness, Dimming Level or
Off). The third wire is a dedicated signal return
(ground) wire. The fourth wire provides power to the
front fog lamp indicator.
HEADLAMP TIME DELAY SYSTEM
The headlamp time delay system is controlled by
the Body Control Module (BCM) via a PCI bus mes-
sage transmitted by the BCM to the FCM to turn off
the headlamps.
OPERATION
AUTOMATIC HEADLAMP SYSTEM
Automatic headlamps are controlled by the Body
Control Module (BCM). With the headlamp switch in
the AUTO position, the BCM will control the head-
lamp, parking, side marker, tail and instrumentation
lamps based on ambient light levels. Ambient light
levels are monitored by the BCM using the Day/
Night signal and Electrochromatic Mirror (ECM)
present from the Compass Mini Trip (CMTC) located
on the front windshield in front of the rear view mir-
ror ECM. Ambient light readings are averaged to
limit cycling the lamps ON and OFF when passing
through areas with varying light levels. The auto-
matic headlamps will only function when the engine
is running with RPM > 450. When the headlamp
switch is in the AUTO position (Automatic mode), the
Headlamp Time Delay system will function when the
ignition switch is placed in any position other than
run/start.
8L - 2 LAMPS/LIGHTING - EXTERIORRS
(3) Install the retaining screws.
(4) Reconnect the battery negative cable.
FRONT FOG LAMP
DIAGNOSIS AND TESTING - FRONT FOG LAMP
When a vehicle experiences problems with the
front fog lamp system, verify the condition of the bat-
tery connections, fuses, charging system, fog lamp
bulbs, wire connectors, relay, high beam switch, and
headlamp switch. Refer to the appropriate wiring
information.
Each vehicle is equipped with various lamp assem-
blies. A good ground is necessary for proper lighting
operation. Grounding is provided by the lamp socket
when it comes in contact with the metal body, or
through a separate ground wire.
When changing lamp bulbs check the socket for
corrosion. If corrosion is present, clean it with a wire
brush.
When it is necessary to remove components to ser-
vice another, it should not be necessary to apply
excessive force or bend a component to remove it.
Before damaging a trim component, verify hidden
fasteners or captured edges are not holding the com-
ponent in place.
FRONT FOG LAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery
cables.1. Clean and secure battery cable clamps and
posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of-charge. Refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical, Battery
System.
6. Poor lighting circuit Z349/Z248
ground.6. Test for voltage drop across Z349/248
ground locations. Refer to Electrical, Wiring
Information.
FOG LAMP BULBS
BURN OUT
FREQUENTLY1. Charging system output too
high.1. Test and repair charging system. Refer to
Electrical, Charging.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
Fig. 7 CHMSL ELECTRICAL CONNECTOR
1 - CHMSL UNIT
2 - CHMSL ELECTRICAL CONNECTOR
RSLAMPS/LIGHTING - EXTERIOR8L-7
CENTER HIGH MOUNTED STOP LAMP UNIT (Continued)