Multi function switch JEEP GRAND CHEROKEE 2003 WJ / 2.G Manual PDF

Component Page
DRIVER SEAT BELT SWITCH........ 8W-80-74
DRIVER SIDE IMPACT SENSOR...... 8W-80-74
EGR SOLENOID (DIESEL)........... 8W-80-74
ELECTRIC BRAKE
(EXCEPT BUILT-UP-EXPORT)...... 8W-80-74
ELECTRONIC SPEED CONTROL
SERVO ......................... 8W-80-74
ENGINE CONTROL MODULE C1
(DIESEL)....................... 8W-80-75
ENGINE CONTROL MODULE C2
(DIESEL)....................... 8W-80-76
ENGINE COOLANT TEMPERATURE
SENSOR (DIESEL)................ 8W-80-77
ENGINE COOLANT TEMPERATURE
SENSOR (GAS)................... 8W-80-77
ENGINE OIL PRESSURE
SENSOR (DIESEL)................ 8W-80-77
ENGINE OIL PRESSURE
SENSOR (GAS)................... 8W-80-78
EVAP/PURGE SOLENOID (GAS)....... 8W-80-78
FRONT POWER OUTLET............ 8W-80-78
FRONT WASHER PUMP............. 8W-80-78
FRONT WIPER MOTOR............. 8W-80-78
FUEL INJECTOR NO. 1 (DIESEL)..... 8W-80-79
FUEL INJECTOR NO. 1 (GAS)........ 8W-80-79
FUEL INJECTOR NO. 2 (DIESEL)..... 8W-80-79
FUEL INJECTOR NO. 2 (GAS)........ 8W-80-79
FUEL INJECTOR NO. 3 (DIESEL)..... 8W-80-79
FUEL INJECTOR NO. 3 (GAS)........ 8W-80-80
FUEL INJECTOR NO. 4 (DIESEL)..... 8W-80-80
FUEL INJECTOR NO. 4 (GAS)........ 8W-80-80
FUEL INJECTOR NO. 5 (DIESEL)..... 8W-80-80
FUEL INJECTOR NO. 5 (GAS)........ 8W-80-81
FUEL INJECTOR NO. 6 (GAS)........ 8W-80-81
FUEL INJECTOR NO. 7 (4.7L)........ 8W-80-81
FUEL INJECTOR NO. 8 (4.7L)........ 8W-80-81
FUEL PRESSURE SENSOR (DIESEL) . . 8W-80-82
FUEL PRESSURE SOLENOID
(DIESEL)....................... 8W-80-82
FUEL PUMP MODULE (GAS)......... 8W-80-82
FUEL TANK MODULE (DIESEL)...... 8W-80-82
GENERATOR (DIESEL).............. 8W-80-82
GENERATOR (GAS)................. 8W-80-83
GLOVE BOX LAMP................. 8W-80-83
HEADLAMP LEVELING SWITCH
(BUILT-UP-EXPORT).............. 8W-80-83
HOOD AJAR SWITCH
(BUILT-UP-EXPORT).............. 8W-80-83
HORN NO. 1....................... 8W-80-83
HORN NO. 2....................... 8W-80-84
HYDRAULIC COOLING MODULE..... 8W-80-84
IDLE AIR CONTROL MOTOR......... 8W-80-84
IGNITION SWITCH C1.............. 8W-80-84
IGNITION SWITCH C2.............. 8W-80-84
INPUT SPEED SENSOR (4.7L)........ 8W-80-85Component Page
INSTRUMENT CLUSTER............ 8W-80-85
INTAKE AIR TEMPERATURE
SENSOR (DIESEL)................ 8W-80-85
INTAKE AIR TEMPERATURE
SENSOR (GAS)................... 8W-80-85
INTAKE PORT SWIRL ACTUATOR
(DIESEL)....................... 8W-80-86
INTRUSION TRANSCEIVER MODULE
(BUILT-UP-EXPORT).............. 8W-80-86
JUNCTION BLOCK BODY
CONTROL MODULE.............. 8W-80-86
JUNCTION BLOCK C1.............. 8W-80-87
JUNCTION BLOCK C2 (LHD)......... 8W-80-88
JUNCTION BLOCK C2 (RHD)......... 8W-80-89
JUNCTION BLOCK C3.............. 8W-80-90
JUNCTION BLOCK C4.............. 8W-80-91
JUNCTION BLOCK C5.............. 8W-80-91
KNOCK SENSOR................... 8W-80-91
LEAK DETECTION PUMP (EXCEPT
BUILT-UP-EXPORT)............... 8W-80-91
LEFT COURTESY LAMP............. 8W-80-91
LEFT DOOR HANDLE COURTESY
LAMP.......................... 8W-80-92
LEFT FOG LAMP................... 8W-80-92
LEFT FRONT DOOR SPEAKER....... 8W-80-92
LEFT FRONT IMPACT SENSOR....... 8W-80-92
LEFT FRONT PARK LAMP........... 8W-80-92
LEFT FRONT PARK/TURN SIGNAL LAMP
(EXCEPT BUILT-UP-EXPORT)...... 8W-80-93
LEFT FRONT SIDE MARKER LAMP
(EXCEPT BUILT-UP-EXPORT)...... 8W-80-93
LEFT FRONT TURN SIGNAL LAMP
(BUILT-UP-EXPORT).............. 8W-80-93
LEFT FRONT WHEEL SPEED
SENSOR........................ 8W-80-93
LEFT HEADLAMP LEVELING MOTOR
(BUILT-UP-EXPORT).............. 8W-80-94
LEFT HIGH BEAM HEADLAMP....... 8W-80-94
LEFT INSTRUMENT PANEL SPEAKER . 8W-80-94
LEFT LIFTGATE AJAR SWITCH....... 8W-80-94
LEFT LOW BEAM HEADLAMP....... 8W-80-94
LEFT MULTI-FUNCTION SWITCH.... 8W-80-95
LEFT REAR DOOR LOCK
MOTOR/AJAR SWITCH............ 8W-80-95
LEFT REAR DOOR SPEAKER......... 8W-80-95
LEFT REAR LAMP ASSEMBLY........ 8W-80-95
LEFT REAR WHEEL SPEED
SENSOR........................ 8W-80-96
LEFT REMOTE RADIO SWITCH...... 8W-80-96
LEFT SIDE REPEATER LAMP
(BUILT-UP-EXPORT).............. 8W-80-96
LEFT VISOR/VANITY LAMP.......... 8W-80-96
LICENSE LAMP NO. 1.............. 8W-80-96
LICENSE LAMP NO. 2.............. 8W-80-97
LIFTGATE FLIP-UP AJAR SWITCH.... 8W-80-97
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 3

Component Page
RIGHT FRONT WHEEL SPEED
SENSOR....................... 8W-80-115
RIGHT HEADLAMP LEVELING MOTOR
(BUILT-UP-EXPORT)............. 8W-80-115
RIGHT HIGH BEAM HEADLAMP..... 8W-80-116
RIGHT INSTRUMENT PANEL
SPEAKER...................... 8W-80-116
RIGHT LIFTGATE AJAR SWITCH..... 8W-80-116
RIGHT LOW BEAM HEADLAMP..... 8W-80-116
RIGHT MULTI-FUNCTION SWITCH . . . 8W-80-116
RIGHT REAR DOOR LOCK
MOTOR/AJAR SWITCH........... 8W-80-117
RIGHT REAR DOOR SPEAKER....... 8W-80-117
RIGHT REAR LAMP ASSEMBLY...... 8W-80-117
RIGHT REAR WHEEL SPEED
SENSOR....................... 8W-80-117
RIGHT REMOTE RADIO SWITCH.... 8W-80-117
RIGHT SIDE REPEATER LAMP
(BUILT-UP-EXPORT)............. 8W-80-118
RIGHT VISOR/VANITY LAMP........ 8W-80-118
SEAT BELT SWITCH............... 8W-80-118
SEAT MODULE C1 (PREMIUM)...... 8W-80-118
SEAT MODULE C2 (PREMIUM)...... 8W-80-119
SENTRY KEY IMMOBILIZER
MODULE...................... 8W-80-119
SHIFTER ASSEMBLY
(C201 DIESEL).................. 8W-80-119
SHIFTER ASSEMBLY (GAS)......... 8W-80-120
SHIFTER ASSEMBLY C1 (DIESEL).... 8W-80-120
SHIFTER ASSEMBLY C2 (DIESEL).... 8W-80-120
SIREN (BUILT-UP-EXPORT)......... 8W-80-120
SPEED CONTROL SWITCH NO. 1.... 8W-80-120
SPEED CONTROL SWITCH NO. 2.... 8W-80-121
SUNROOF CONTROL MODULE...... 8W-80-121
SUNROOF MOTOR C1.............. 8W-80-121
SUNROOF MOTOR C2.............. 8W-80-121
SUNROOF SWITCH................ 8W-80-121Component Page
TEMPERATURE VALVE
ACTUATOR (MTC)............... 8W-80-122
THROTTLE POSITION
SENSOR (4.0L).................. 8W-80-122
THROTTLE POSITION
SENSOR (4.7L).................. 8W-80-122
TRAILER TOW BRAKE
LAMP RELAY................... 8W-80-122
TRAILER TOW CIRCUIT
BREAKER...................... 8W-80-122
TRAILER TOW CONNECTOR........ 8W-80-123
TRAILER TOW LEFT TURN
RELAY........................ 8W-80-123
TRAILER TOW RIGHT TURN
RELAY........................ 8W-80-123
TRANSFER CASE POSITION
SENSOR....................... 8W-80-123
TRANSMISSION CONTROL
MODULE (4.7L)................. 8W-80-124
TRANSMISSION CONTROL
MODULE C1 (DIESEL)........... 8W-80-125
TRANSMISSION CONTROL
MODULE C2 (DIESEL)........... 8W-80-125
TRANSMISSION SOLENOID (4.0L).... 8W-80-125
TRANSMISSION SOLENOID
ASSEMBLY (DIESEL)............ 8W-80-126
TRANSMISSION SOLENOID/TRS
ASSEMBLY (4.7L)................ 8W-80-126
UNDERHOOD LAMP............... 8W-80-126
VEHICLE INFORMATION CENTER . . . 8W-80-127
VISCOUS/CABIN HEATER
(DIESEL)...................... 8W-80-127
WASHER FLUID LEVEL SWITCH.... 8W-80-127
WASTEGATE SOLENOID
(DIESEL)...................... 8W-80-127
WATER IN FUEL SENSOR
(DIESEL)...................... 8W-80-127
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 5

LEFT MULTI-FUNCTION SWITCH - WHITE 11 WAY
CAV CIRCUIT FUNCTION
1 L27 20WT/TN FOG LAMP SWITCH SENSE
2 Z234 20BK GROUND
3- -
4 L80 20WT/DG HEADLAMP SWITCH RETURN
5 L309 20PK/LG HIGH BEAM RELAY CONTROL
6 L40 20BR HIGH BEAM SWITCH SENSE
7 L302 20LB/YL RIGHT TURN SWITCH SENSE
8 L305 20LB/WT LEFT TURN SWITCH SENSE
9 L91 20DB/PK HAZARD SWITCH SENSE
10 E19 20RD PANEL LAMPS DIMMER SIGNAL
11 G52 20YL HEADLAMP SWITCH MUX
LEFT REAR DOOR LOCK MOTOR/AJAR SWITCH - BLACK 4 WAY
CAV CIRCUIT FUNCTION
1 G77 18TN/YL LEFT REAR DOOR AJAR SWITCH SENSE
2 Z1 18BK GROUND
3 P36 18PK/VT DOOR UNLOCK DRIVER
4 P35 18OR/VT DOOR LOCK DRIVER
LEFT REAR DOOR SPEAKER - WHITE 3 WAY
CAV CIRCUIT FUNCTION
1 X51 18WT/VT (BASE) LEFT REAR DOOR SPEAKER (+)
1 X91 18WT/VT (PREMIUM) LEFT REAR DOOR SPEAKER (+)
2- -
3 X57 18TN/DG (BASE) LEFT REAR DOOR SPEAKER (-)
3 X93 18TN/DG (PREMIUM) LEFT REAR DOOR SPEAKER (-)
LEFT REAR LAMP ASSEMBLY - BLACK 6 WAY
CAV CIRCUIT FUNCTION
1 L1 18VT/BK BACK-UP LAMP FEED
2 L95 18DG/YL (BUILT-UP-EXPORT) REAR FOG LAMP RELAY OUTPUT
3 L7 18BK/YL PARK LAMP RELAY OUTPUT
4 L63 18DG/RD LEFT TURN SIGNAL
5 Z150 18BK GROUND
6 L50 18WT/TN PRIMARY BRAKE SWITCH SIGNAL
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 95

RIGHT HIGH BEAM HEADLAMP - BLACK 2 WAY
CAV CIRCUIT FUNCTION
A Z1 18BK GROUND
B L34 18RD/OR FUSED RIGHT HIGH BEAM OUTPUT
RIGHT INSTRUMENT PANEL SPEAKER - WHITE 2 WAY
CAV CIRCUIT FUNCTION
1 X86 18OR/RD RIGHT INSTRUMENT PANEL SPEAKER (+)
2 X84 18OR/BK RIGHT INSTRUMENT PANEL SPEAKER (-)
RIGHT LIFTGATE AJAR SWITCH - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 Z1 20BK GROUND
2 G78 20TN/BK LIFTGATE AJAR SWITCH SENSE
RIGHT LOW BEAM HEADLAMP - GRAY 2 WAY
CAV CIRCUIT FUNCTION
A Z1 18BK GROUND
B L44 18VT/RD FUSED RIGHT LOW BEAM OUTPUT
RIGHT MULTI-FUNCTION SWITCH - WHITE 10 WAY
CAV CIRCUIT FUNCTION
1 V23 20BR/PK FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
2 V20 18BK/WT REAR WASHER PUMP MOTOR CONTROL
3 V10 20BR WASHER PUMP SWITCH SENSE
4- -
5 V13 18BR/LG REAR WIPER MOTOR CONTROL
6 V22 18BR/YL REAR WIPER MOTOR DELAY CONTROL
7 V9 20WT/BK WINDSHIELD WIPER SWITCH RETURN
8 V52 20DG/RD WINDSHIELD WIPER SWITCH MUX
9 V48 20RD/GY WIPER HIGH CONTROL
10 - -
8W - 80 - 116 8W-80 CONNECTOR PIN-OUTWJ

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Left Front Park/Turn Signal
Lamp (Except Built-Up-Export)BK At Lamp N/S
Left Front Side Marker Lamp
(Except Built-Up-Export)WT At Lamp N/S
Left Front Turn Signal Lamp
(Built-Up-Export)WT At Lamp N/S
Left Front Wheel Speed
SensorGY At Left Front Wheel Opening 4
Left Headlamp Leveling Motor
(Built-Up-Export)BK At Motor N/S
Left High Beam Headlamp BK At Lamp N/S
Left Instrument Panel Speaker WT At Speaker 19, 20
Left Liftgate Ajar Switch BK In Liftgate 38
Left Low Beam Headlamp GY At Lamp N/S
Left Multi-Function Switch WT On Steering Column 23
Left Rear Door Lock Motor/Ajar
SwitchBK In Left Rear Door 28
Left Rear Door Speaker WT In Left Rear Door 28
Left Rear Lamp Assembly BK At Lamp Assembly 37
Left Rear Wheel Speed Sensor GY Near Left Rear Wheel 33, 35
Left Remote Radio Switch BK At Switch in Steering Wheel N/S
Left Side Impact Sensor BK Left Body N/S
Left Side Repeater Lamp
(Built-Up-Export)BK On Left Front Fender 3, 4
Left Visor/Vanity Lamp BK At Lamp N/S
License Lamp No.1 BK At Lamp N/S
License Lamp No.2 BK At Lamp N/S
Liftgate Flip-Up Ajar Switch GY In Liftgate 38
Liftgate Flip-Up Push Button
SwitchBK In Liftgate N/S
Liftgate Flip-Up Release
SolenoidBK In Liftgate 38
Liftgate Lock Motor BK In Liftgate 38
Line Pressure Sensor (4.7L) BK Rear of Transmission N/S
Manifold Absolute Pressure
Sensor (4.0L)BK At Throttle Body 9
Manifold Absolute Pressure
Sensor (4.7L)BK Right Side of Engine 13
Manual Temperature Control -
C1 (MTC)WT Center of Instrument Panel N/S
Manual Temperature Control -
C2 (MTC)WT Center of Instrument Panel N/S
Mass Air Flow sensor (Diesel) BK Near T/O for G105 8
Mode Door Motor/Actuator
(AZC)BK Right Center of Instrument Panel N/S
WJ8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 7
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Right Front Park/Turn Signal
Lamp (Except Built-Up-Export)BK At Lamp N/S
Right Front Side Marker Lamp
(Except Built-Up-Export)WT At Lamp N/S
Right Front Turn Signal Lamp
(Built-Up-Export)WT At Lamp N/S
Right Front Wheel Speed
SensorGY In Right Front Wheel Opening N/S
Right Headlamp Leveling
Motor (Built-Up-Export)BK At Motor N/S
Right High Beam Headlamp BK At Lamp N/S
Right Instrument Panel
SpeakerWT At Speaker 19, 20
Right Liftgate Ajar Switch BK In Liftgate 38
Right Low Beam Headlamp GY At Lamp N/S
Right Multi-Function Switch WT On Steering Column 23
Right Rear Door Lock
Motor/Ajar SwitchBK In Right Rear Door 29
Right Rear Door Speaker WT In Right Rear Door 29
Right Rear Lamp Assembly BK At Lamp Assembly 37
Right Rear Wheel Speed
SensorBK Near Right Rear Wheel 33, 35
Right Remote Radio Switch BK At Switch in Steering Wheel N/S
Right Side Repeater Lamp
(Built-Up-Export)BK On Right Front Fender 5
Right Visor/Vanity Lamp BK At Lamp N/S
Seat Belt Switch WT At Driver Seat N/S
Seat Module - C1 (Premium) BK Under Driver Seat N/S
Seat Module - C2 (Premium) OR Under Driver Seat N/S
Sentry Key Immobilizer Module BK On Steering Column 23
Shifter Assembly (Gas) WT Between Front Seats 23
Shifter Assembly C1 (Diesel) Between Front Seats N/S
Shifter Assembly C2 (Diesel) Between Front Seats N/S
Siren (Built-up-export) Left Front Fender 3, 4
Speed Control Switch NO. 1 BK On Steering Wheel N/S
Speed Control Switch NO. 2 BK On Steering Wheel N/S
Sunroof Control Module At Sunroof 32
Sunroof Motor C1 WT At Sunroof N/S
Sunroof Motor C2 BK In Overhead N/S
Sunroof Switch GY At Switch N/S
Temperature Valve Actuator
(MTC)BK On HVAC Housing N/S
Throttle Position Sensor (4.0L) BK Left Side of Engine 9
Throttle Position Sensor (4.7L) WT Left Side of Engine 13
8W - 91 - 10 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

(10) Disconnect the multifuction switch (Fig. 9)
and ignition switch harness.
(11) Remove the multifuction switch screw from
underneath the switch (Fig. 10). Slide the multifuc-
tion switch and clock spring off the column as an
assembly (Fig. 11).(12) Turn the ignition key to the on position then
release and remove the shifter interlock cable (Fig.
12) from the ignition lock cylinder housing.
Fig. 9 Multifuction Switch Harness
1 - MULTIFUNCTION SWITCH
2 - MULTIFUNCTION SWITCH HARNESS
Fig. 10 Multifuction
1 - CLOCK SPRING
2 - SCREW
3 - MULTI-FUNCTION SWITCH MOUNTING HOUSING
Fig. 11 Multifuction Switch And Clock Spring
1 - MULTI-FUNCTION SWITCH ASSEMBLY
2 - CLOCKSPRING
Fig. 12 Shifter Interlock Cable
1 - LOCK CYLINDER HOUSING
2 - INTERLOCK CABLE
19 - 10 COLUMNWJ
COLUMN (Continued)

(12) Remove the screw that secures the lower tilt-
ing steering column shroud to the steering column
multi-function switch mounting housing (Fig. 2).
(13) Unsnap the two halves of the tilting steering
column shroud from each other and remove both
halves from the steering column.
(14) Disconnect the instrument panel wire harness
connectors from the following steering column compo-
nents (Fig. 3):
²the two lower clockspring connector receptacles
²the left multi-function switch connector recepta-
cle
²the right multi-function switch connector recep-
tacle
²the two ignition switch connector receptacles
²the shifter interlock solenoid connector recepta-
cle
²if the vehicle is so equipped, the Sentry Key
Immobilizer Module (SKIM) connector receptacle.
(15) Turn the ignition switch to the On position,
then release and remove the shifter interlock cable
connector from the ignition lock housing receptacle.
(16) Turn the ignition switch back to the Lock
position to prevent steering wheel rotation and theloss of clockspring centering following steering col-
umn removal.
(17) Remove the bolt that secures the coupler to
the lower steering column shaft (Fig. 4).
Fig. 2 Steering Column Shrouds Remove/Install
1 - UPPER TILTING COLUMN SHROUD
2 - FIXED COLUMN SHROUD
3 - LOWER TILTING COLUMN SHROUD
4 - SCREW
Fig. 3 Steering Column Connections
1 - LEFT MULTIFUNCTION SWITCH CONNECTOR
2 - LOWER CLOCKSPRING CONNECTORS
3 - RIGHT MULTIFUNCTION SWITCH CONNECTOR
4 - SHIFTER INTERLOCK CABLE CONNECTOR
5 - SHIFTER INTERLOCK SOLENOID CONNECTOR
6 - IGNITION SWITCH CONNECTOR RECEPTACLES
7 - SKIM CONNECTOR
Fig. 4 Steering Column Mounting
1 - COLUMN MOUNTING NUTS
2 - COUPLER BOLT
23 - 38 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL SYSTEM (Continued)

(23) Reconnect the instrument panel wire harness
connectors to the following floor panel transmission
tunnel components:
²the Airbag Control Module (ACM) connector
receptacle
²the park brake switch terminal
²the transmission shifter connector receptacle.
(24) Reconnect the left and right body wire har-
ness connectors, the Ignition Off Draw (IOD) wire
harness connector and the fused B(+) wire harness
connector to the connector receptacles of the Junction
Block (JB) and tighten the connector screws (Fig. 5).
Tighten the screws to 4 N´m (36 in. lbs.).
(25) Engage the lower steering column shaft with
the steering shaft coupler and position the steering
column to the mounting studs on the instrument
panel steering column support bracket (Fig. 4).
(26) Install and tighten the four nuts that secure
the steering column to the studs on the instrument
panel steering column support bracket. Tighten the
nuts to 11.8 N´m (105 in. lbs.).
(27) Install and tighten the bolt that secures the
coupler to the lower steering column shaft. Tighten
the bolt to 49 N´m (36 ft. lbs.).
(28) Turn the ignition switch to the On position,
then install the shifter interlock cable connector into
the ignition lock housing receptacle.
(29) Reconnect the instrument panel wire harness
connectors to the following steering column compo-
nents (Fig. 3):
²the two lower clockspring connector receptacles
²the left multi-function switch connector recepta-
cle
²the right multi-function switch connector recep-
tacle
²the two ignition switch connector receptacles
²the shifter interlock solenoid connector recepta-
cle
²if the vehicle is so equipped, the Sentry Key
Immobilizer Module (SKIM) connector receptacle.
(30) Position the lower tilting steering column
shroud to the steering column multi-function switchmounting housing, then install and tighten the screw
that secures the shroud to the housing (Fig. 2).
Tighten the screw to 1.9 N´m (17 in. lbs.).
(31) Position the upper tilting steering column
shroud over the steering column. Align the upper and
lower shrouds with each other and snap the two
halves together.
(32) Reinstall the steering column bracket onto the
instrument panel steering column support bracket.
(Refer to 23 - BODY/INSTRUMENT PANEL/IP
STEERING COLUMN BRACKET - INSTALLA-
TION).
(33) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(34) Reinstall the cluster bezel onto the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/CLUSTER BEZEL - INSTALLATION).
(35) Reinstall the fuse cover onto the Junction
Block (JB). (Refer to 8 - ELECTRICAL/POWER DIS-
TRIBUTION/FUSE COVER - INSTALLATION).
(36) Reinstall the console onto the floor panel
transmission tunnel. (Refer to 23 - BODY/INTERI-
OR/FLOOR CONSOLE - INSTALLATION).
(37) Reinstall the trim panels onto the right and
left inner cowl sides. (Refer to 23 - BODY/INTERI-
OR/COWL TRIM - INSTALLATION).
(38) Reinstall the scuff plates onto the right and
left front door sills. (Refer to 23 - BODY/INTERIOR/
DOOR SILL SCUFF PLATE - INSTALLATION).
(39) Reinstall the top cover onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL TOP COVER - INSTALLA-
TION).
(40) Reinstall the trim onto the right and left
A-pillars. (Refer to 23 - BODY/INTERIOR/A-PILLAR
TRIM - INSTALLATION).
(41) Reconnect the battery negative cable.
23 - 44 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL SYSTEM (Continued)

tive system and seal the evaporative system so the
leak detection test can be run.
The primary components within the assembly are:
A three port solenoid that activates both of the func-
tions listed above; a pump which contains a switch,
two check valves and a spring/diaphragm, a canister
vent valve (CVV) seal which contains a spring loaded
vent seal valve.
Immediately after a cold start, between predeter-
mined temperature thresholds limits, the three port
solenoid is briefly energized. This initializes the
pump by drawing air into the pump cavity and also
closes the vent seal. During non test conditions the
vent seal is held open by the pump diaphragm
assembly which pushes it open at the full travel posi-
tion. The vent seal will remain closed while the
pump is cycling due to the reed switch triggering of
the three port solenoid that prevents the diaphragm
assembly from reaching full travel. After the brief
initialization period, the solenoid is de-energized
allowing atmospheric pressure to enter the pump
cavity, thus permitting the spring to drive the dia-
phragm which forces air out of the pump cavity and
into the vent system. When the solenoid is energized
and de energized, the cycle is repeated creating flow
in typical diaphragm pump fashion. The pump is con-
trolled in 2 modes:
Pump Mode:The pump is cycled at a fixed rate to
achieve a rapid pressure build in order to shorten the
overall test length.
Test Mode:The solenoid is energized with a fixed
duration pulse. Subsequent fixed pulses occur when
the diaphragm reaches the Switch closure point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5º
water. The cycle rate of pump strokes is quite rapid
as the system begins to pump up to this pressure. As
the pressure increases, the cycle rate starts to drop
off. If there is no leak in the system, the pump would
eventually stop pumping at the equalized pressure. If
there is a leak, it will continue to pump at a rate rep-
resentative of the flow characteristic of the size of the
leak. From this information we can determine if the
leak is larger than the required detection limit (cur-
rently set at .040º orifice by CARB). If a leak is
revealed during the leak test portion of the test, the
test is terminated at the end of the test mode and no
further system checks will be performed.
After passing the leak detection phase of the test,
system pressure is maintained by turning on the
LDP's solenoid until the purge system is activated.
Purge activation in effect creates a leak. The cycle
rate is again interrogated and when it increases due
to the flow through the purge system, the leak check
portion of the diagnostic is complete.The canister vent valve will unseal the system
after completion of the test sequence as the pump
diaphragm assembly moves to the full travel position.
Evaporative system functionality will be verified by
using the stricter evap purge flow monitor. At an
appropriate warm idle the LDP will be energized to
seal the canister vent. The purge flow will be clocked
up from some small value in an attempt to see a
shift in the 02 control system. If fuel vapor, indicated
by a shift in the 02 control, is present the test is
passed. If not, it is assumed that the purge system is
not functioning in some respect. The LDP is again
turned off and the test is ended.
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the Air Fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
The PCM is programmed to maintain the optimum
air/fuel ratio of 14.7 to 1. This is done by making
short term corrections in the fuel injector pulse width
based on the O2S sensor output. The programmed
memory acts as a self calibration tool that the engine
controller uses to compensate for variations in engine
specifications, sensor tolerances and engine fatigue
over the life span of the engine. By monitoring the
actual fuel-air ratio with the O2S sensor (short term)
and multiplying that with the program long-term
(adaptive) memory and comparing that to the limit,
it can be determined whether it will pass an emis-
sions test. If a malfunction occurs such that the PCM
cannot maintain the optimum A/F ratio, then the
MIL will be illuminated.
CATALYST MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide.
Normal vehicle miles or engine misfire can cause a
catalyst to decay. This can increase vehicle emissions
25 - 18 EMISSIONS CONTROLWJ
EMISSIONS CONTROL (Continued)