2003 JEEP GRAND CHEROKEE multiple

operates the front wipers at the programmed speed
and intervals requested by the RSM to maintain vis-
ibility through the windshield.
²Continuous Wipe Mode- The control knob on
the control stalk of the right (wiper) multi-function
switch has two continuous wipe positions, Low and
High. When selected, these switch positions will
cause the two-speed front wiper motor to operate in a
continuous low or high speed cycle.
²Headlamps On With Wipers- The BCM pro-
vides an automatic headlamps on with wipers feature
for models equipped with the optional automatic
headlamps. This is a customer programmable fea-
ture. If this feature is enabled, the headlamps will
turn on automatically when the windshield wipers
are turned on; and, if the headlamps were turned on
automatically when the wipers were turned on, they
will turn off automatically when the wipers are
turned off. In models equipped with the optional
automatic wiper feature, when the automatic wiper
mode is selected the headlamps will turn on auto-
matically only after the wipers complete three auto-
matic wipe cycles within about thirty seconds, and
they will turn off automatically after three minutes
elapse without any automatic wipe cycles. (Refer to 8
- ELECTRICAL/OVERHEAD CONSOLE - STAN-
DARD PROCEDURE - ELECTRONIC VEHICLE
INFORMATION CENTER PROGRAMMING).
²Mist Wipe Mode- The control stalk of the right
(wiper) multi-function switch has a momentary Mist
position. When selected, this switch position will
operate the front wipers in a low speed continuous
cycle for as long as the switch is held closed, then
will complete the current wipe cycle and park the
front wiper blades near the base of the windshield
when the switch is released.
²Speed Sensitive Intermittent Wipe Mode-
Except on models equipped with the optional auto-
matic wiper system, the internal circuitry of both the
right (wiper) multi-function switch and the BCM
work in concert to provide an intermittent wipe mode
with five delay interval selections. The BCM auto-
matically adjusts each manually selected delay inter-
val to compensate for vehicle speed.
²Washer Mode- When the momentary front
wash position of the control stalk for the right
(wiper) multi-function switch is selected with the
front wiper system operating in a continuous wipe
mode, washer fluid will be dispensed onto the wind-
shield glass through the washer nozzles for as long
as the washer switch is held closed. When the front
washer switch is actuated with the front wiper sys-
tem operating in an intermittent wipe mode, washer
fluid is still dispensed until the switch is released;
however, the front wipers will operate in a low speed
continuous cycle from the time the washer switch isclosed until several wipe cycles after the switch is
released, before returning to the selected intermit-
tent wipe mode.
²Wipe-After-Wash Mode- When the momentary
front wash position of the control stalk for the right
(wiper) multi-function switch is selected with the
front wiper system turned Off, the internal circuitry
of the BCM provides a wipe-after-wash feature.
When selected, this feature will operate the front
washer pump/motor and the front wipers for as long
as the front washer switch is held closed, then pro-
vide several additional wipe cycles after the switch is
released before parking the front wiper blades near
the base of the windshield.
OPERATION
The front wiper and washer system is designed to
provide the vehicle operator with a convenient, safe,
and reliable means of maintaining visibility through
the windshield glass. The various components of this
system are designed to convert electrical energy pro-
duced by the vehicle electrical system into the
mechanical action of the wiper blades to wipe the
outside surface of the glass, as well as into the
hydraulic action of the washer system to apply
washer fluid stored in an on-board reservoir to the
area of the glass to be wiped. When combined, these
components provide the means to effectively main-
tain clear visibility for the vehicle operator by remov-
ing excess accumulations of rain, snow, bugs, mud, or
other minor debris that might be encountered while
driving the vehicle under numerous types of inclem-
ent operating conditions from the outside windshield
glass surface.
The vehicle operator initiates all front wiper and
washer system functions with the control stalk of the
right (wiper) multi-function switch that extends from
the right side of the steering column, just below the
steering wheel. Rotating the control knob on the end
of the right (wiper) multi-function switch control
stalk selects the Off, Delay (on models not equipped
with the optional automatic wiper system), Auto (on
models equipped with the optional automatic wiper
system), Low, or High front wiper system operating
modes. In the Delay mode, the control knob also
allows the vehicle operator to select from one of five
intermittent wipe Delay intervals. In the Auto mode,
the control knob also allows the vehicle operator to
select from one of five automatic wiper sensitivity
levels. Pulling the right control stalk downwards
actuates the momentary front wiper system Mist
mode switch, while pulling the right control stalk
towards the steering wheel actuates the front washer
system switch. The multi-function switch provides
hard wired resistor multiplexed inputs to the Body
Control Module (BCM) for all of the front wiper sys-
8R - 4 FRONT WIPERS/WASHERSWJ
FRONT WIPERS/WASHERS (Continued)

²Continuous Rear Wipe Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control sleeve provides one continu-
ous rear wipe switch position.
²Front Washer Mode- The internal circuitry
and hardware of the right (wiper) multi-function
switch control stalk provide front washer system
operation.
²Front Wipe-After-Wash Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control stalk provide a wipe-after-
wash mode.
²Front Wiper Mist Mode- The internal cir-
cuitry and hardware of the right (wiper) multi-func-
tion switch control stalk provide a front wiper system
mist mode.
²Intermittent Front Wipe Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control knob provide an intermittent
front wipe mode with five delay interval positions,
except on models equipped with the optional auto-
matic wiper system.
²Intermittent Rear Wipe Mode- The internal
circuitry and hardware of the right (wiper) multi-
function switch control ring provide one fixed inter-
val intermittent rear wipe mode switch position.
²Rear Washer Mode- The internal circuitry and
hardware of the right (wiper) multi-function switch
control stalk provide rear washer system operation.
OPERATION
The right (wiper) multi-function switch uses a com-
bination of resistor multiplexed and conventionally
switched outputs to control the many functions and
features it provides. The switch receives battery cur-
rent on a fused ignition switch output (run-acc) cir-
cuit from a fuse in the Junction Block (JB) whenever
the ignition switch is in the On or Accessory posi-
tions, and receives ground from the Body Control
Module (BCM) on a windshield wiper switch return
circuit. The right (wiper) multi-function switch may
be diagnosed using conventional diagnostic tools and
methods.
Following are descriptions of how the right (wiper)
multi-function switch control stalk operates to control
the functions and features it provides:
²Automatic Wipe Mode- On models equipped
with the optional automatic wiper system, the control
knob on the end of the right (wiper) multi-function
switch control stalk is rotated to one of five minor
intermediate detents to select the desired automatic
wipe sensitivity level. The control knob is rotated
rearward (counterclockwise) to reduce the sensitivity
(increase the interval between wipes), or forward
(clockwise) to increase the sensitivity (decrease the
interval between wipes). The right (wiper) multi-function switch provides a resistor multiplexed out-
put to the Body Control Module (BCM) on a
windshield wiper switch mux circuit. The BCM
responds by sending an electronic message to the
Rain Sensor Module (RSM) over the Programmable
Communications Interface (PCI) data bus indicating
the selected sensitivity level, and by operating the
front wiper system based upon electronic wipe com-
mands received from the RSM over the PCI data bus.
²Continuous Front Wipe Modes- The control
knob on the end of the right (wiper) multi-function
switch control stalk is rotated to an intermediate
detent that is one detent rearward (counterclockwise)
from the full forward (clockwise) detent to select the
low speed continuous front wiper mode, or to its full
forward (clockwise) detent to select the high speed
continuous front wiper mode. For the low speed
mode, the multi-function switch provides a resistor
multiplexed output to the Body Control Module
(BCM) on a windshield wiper switch mux circuit, and
the BCM responds by energizing the wiper on/off
relay in the Power Distribution Center (PDC) for the
front low speed continuous wipe mode. For the high
speed mode, the multi-function switch provides the
same resistor multiplexed output to the BCM on the
windshield wiper switch mux circuit as the low speed
mode, but also provides a ground output to the BCM
on a wiper high control circuit. The BCM responds to
these inputs by energizing the wiper on/off relay and
the wiper high/low relay in the PDC for the front
high speed continuous wipe mode.
²Continuous Rear Wipe Mode- The control
ring on the right (wiper) multi-function switch con-
trol stalk is rotated to the most forward (clockwise)
detent to select the continuous rear wiper mode. The
multi-function switch provides a battery current out-
put to the rear wiper motor on a rear wiper motor
control circuit to signal the rear wiper module to
operate the rear wiper motor in the continuous wipe
mode.
²Front Washer Mode- The control stalk of the
right (wiper) multi-function switch is pulled toward
the steering wheel to momentarily activate the front
washer pump/motor in the front washer mode. The
front washer pump will continue to operate in the
front washer mode until the control stalk is released.
The right (wiper) multi-function switch provides a
battery current output on a washer pump motor
switch output circuit to energize the front washer
pump in the front washer mode.
²Front Wiper Mist Mode- The control stalk of
the right (wiper) multi-function switch is pushed
towards the floor to momentarily activate the front
wiper motor in the mist mode. The front wiper motor
will continue to operate in the mist mode until the
control stalk is released. The right (wiper) multi-
WJFRONT WIPERS/WASHERS 8R - 21
RIGHT MULTI-FUNCTION SWITCH (Continued)

function switch provides a resistor multiplexed out-
put to the Body Control Module (BCM) on a
windshield wiper switch mux circuit, and the BCM
responds by energizing the wiper on/off relay in the
Power Distribution Center (PDC) to operate the front
wiper motor momentarily at low speed to provide the
front wiper mist mode.
²Intermittent Front Wipe Mode- On models
not equipped with the optional automatic wiper sys-
tem, the control knob on the end of the right (wiper)
multi-function switch control stalk is rotated to one
of five minor intermediate detents to select the
desired intermittent front wipe delay interval. The
control knob is rotated rearward (counterclockwise)
to increase the delay, or forward (clockwise) to
decrease the delay. The right (wiper) multi-function
switch provides a resistor multiplexed output to the
Body Control Module (BCM) on a windshield wiper
switch mux circuit. The BCM responds by monitoring
electronic vehicle speed messages received from the
Powertrain Control Module (PCM) over the Program-
mable Communications Interface (PCI) data bus,
then energizing the wiper on/off relay in the Power
Distribution Center (PDC) to operate the front wiper
motor at the proper delay intervals.
²Intermittent Rear Wipe Mode- The control
ring on the right (wiper) multi-function switch con-
trol stalk is rotated to the center detent to select the
intermittent rear wiper mode. The right (wiper)
multi-function switch provides a battery current out-
put to the rear wiper motor on a rear wiper motor
delay control circuit to signal the rear wiper module
to operate the rear wiper in the intermittent wipe
mode.
²Rear Washer Mode- The right (wiper) multi-
function switch control stalk is pushed forward
toward the instrument panel to a momentary posi-
tions to activate the rear washer pump/motor in the
rear washer mode. The rear washer pump will con-
tinue to operate in the rear washer mode until the
control stalk is released. The right (wiper) multi-
function switch provides battery current on a rear
washer pump motor control circuit to energize the
rear washer pump in the rear washer mode.DIAGNOSIS AND TESTING - RIGHT MULTI-
FUNCTION SWITCH
Be certain to perform the diagnosis for the front
wiper system, front washer system, rear wiper sys-
tem, and/or rear washer system before testing the
right multi-function switch. (Refer to 8 - ELECTRI-
CAL/FRONT WIPERS/WASHERS - DIAGNOSIS
AND TESTING) or (Refer to 8 - ELECTRICAL/REAR
WIPERS/WASHERS - DIAGNOSIS AND TESTING).
Refer to the appropriate wiring information. The wir-
ing information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE PASSIVE RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG. SIDE CURTAIN AIRBAG,
FRONT IMPACT SENSOR, SIDE IMPACT SENSOR,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE PASSIVE RESTRAINT
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the right multi-function switch from
the steering column and disconnect the instrument
panel wire harness connector for the switch from the
switch connector receptacle.
(3) Using an ohmmeter, check the right multi-func-
tion switch continuity and resistances at the switch
terminals as shown in the Right Multi-Function
Switch test chart (Fig. 17).
8R - 22 FRONT WIPERS/WASHERSWJ
RIGHT MULTI-FUNCTION SWITCH (Continued)

DESCRIPTION - CONNECTOR, GROUND AND
SPLICE INFORMATION
CAUTION: Not all connectors are serviced. Some
connectors are serviced only with a harness. A typ-
ical example might be the Supplemental Restraint
System connectors. Always check parts availability
before attempting a repair.
IDENTIFICATION
In-line connectors are identified by a number, as
follows:
²In-line connectors located in the engine compart-
ment are C100 series numbers
²In-line connectors located in the Instrument
Panel area are C200 series numbers.
²In-line connectors located in the body are C300
series numbers.
²Jumper harness connectors are C400 series
numbers.
²Grounds and ground connectors are identified
with a ªGº and follow the same series numbering as
the in-line connectors.
²Splices are identified with an ªSº and follow the
same series numbering as the in-line connectors.
²Component connectors are identified by the com-
ponent name instead of a number. Multiple connec-
tors on a component use a C1, C2, etc. identifier.
LOCATIONS
Section 8W-91 contains connector/ground/splice
location illustrations. The illustrations contain the
connector name (or number)/ground number/splice
number and component identification. Connector/
ground/splice location charts in section 8W-91 refer-
ence the figure numbers of the illustrations.
The abbreviation T/O is used in the component
location section to indicate a point in which the wir-
ing harness branches out to a component. The abbre-
viation N/S means Not Shown in the illustrations
WARNING
WARNINGS - GENERAL
WARNINGSprovide information to prevent per-
sonal injury and vehicle damage. Below is a list of
general warnings that should be followed any time a
vehicle is being serviced.
WARNING: ALWAYS WEAR SAFETY GLASSES FOR
EYE PROTECTION.
WARNING: USE SAFETY STANDS ANYTIME A PRO-
CEDURE REQUIRES BEING UNDER A VEHICLE.WARNING: BE SURE THAT THE IGNITION SWITCH
ALWAYS IS IN THE OFF POSITION, UNLESS THE
PROCEDURE REQUIRES IT TO BE ON.
WARNING: SET THE PARKING BRAKE WHEN
WORKING ON ANY VEHICLE. AN AUTOMATIC
TRANSMISSION SHOULD BE IN PARK. A MANUAL
TRANSMISSION SHOULD BE IN NEUTRAL.
WARNING: OPERATE THE ENGINE ONLY IN A
WELL-VENTILATED AREA.
WARNING: KEEP AWAY FROM MOVING PARTS
WHEN THE ENGINE IS RUNNING, ESPECIALLY THE
FAN AND BELTS.
WARNING: TO PREVENT SERIOUS BURNS, AVOID
CONTACT WITH HOT PARTS SUCH AS THE RADIA-
TOR, EXHAUST MANIFOLD(S), TAIL PIPE, CATA-
LYTIC CONVERTER AND MUFFLER.
WARNING: DO NOT ALLOW FLAME OR SPARKS
NEAR THE BATTERY. GASES ARE ALWAYS
PRESENT IN AND AROUND THE BATTERY.
WARNING: ALWAYS REMOVE RINGS, WATCHES,
LOOSE HANGING JEWELRY AND AVOID LOOSE
CLOTHING.
DIAGNOSIS AND TESTING - WIRING HARNESS
TROUBLESHOOTING TOOLS
When diagnosing a problem in an electrical circuit
there are several common tools necessary. These tools
are listed and explained below.
²Jumper Wire - This is a test wire used to con-
nect two points of a circuit. It can be used to bypass
an open in a circuit.
WARNING: NEVER USE A JUMPER WIRE ACROSS
A LOAD, SUCH AS A MOTOR, CONNECTED
BETWEEN A BATTERY FEED AND GROUND.
²Voltmeter - Used to check for voltage on a cir-
cuit. Always connect the black lead to a known good
ground and the red lead to the positive side of the
circuit.
CAUTION: Most of the electrical components used
in today's vehicles are Solid State. When checking
voltages in these circuits, use a meter with a 10 -
megohm or greater impedance rating.
WJ8W-01 WIRING DIAGRAM INFORMATION 8W - 01 - 7
WIRING DIAGRAM INFORMATION (Continued)

INSTALLATION........................253
OUTPUT SPEED SENSOR
DESCRIPTION........................254
OPERATION..........................254
REMOVAL............................254
INSTALLATION........................254
OVERDRIVE SWITCH
DESCRIPTION........................254
OPERATION..........................254
PARK LOCK CABLE
REMOVAL............................255
INSTALLATION........................255
PISTONS
DESCRIPTION........................256
OPERATION..........................256
PLANETARY GEARTRAIN
DESCRIPTION........................258
OPERATION..........................260
DISASSEMBLY........................260
CLEANING...........................260
INSPECTION.........................260
ASSEMBLY...........................261
SHIFT MECHANISM
DESCRIPTION........................261
OPERATION..........................261
REMOVAL............................261
INSTALLATION........................263
SOLENOID SWITCH VALVE
DESCRIPTION........................263
OPERATION..........................263
SOLENOIDS
DESCRIPTION........................263OPERATION..........................264
TORQUE CONVERTER
DESCRIPTION........................264
OPERATION..........................268
REMOVAL............................269
INSTALLATION........................269
TRANSMISSION CONTROL RELAY
DESCRIPTION........................270
OPERATION..........................270
TRANSMISSION RANGE SENSOR
DESCRIPTION........................270
OPERATION..........................270
TRANSMISSION SOLENOID/TRS ASSEMBLY
DESCRIPTION........................271
OPERATION..........................271
REMOVAL............................272
INSTALLATION........................272
TRANSMISSION TEMPERATURE SENSOR
DESCRIPTION........................272
OPERATION..........................272
VALVE BODY
DESCRIPTION........................273
OPERATION..........................273
REMOVAL............................274
DISASSEMBLY........................275
CLEANING...........................277
INSPECTION.........................277
ASSEMBLY...........................278
INSTALLATION........................279
AUTOMATIC TRANSMISSION -
545RFE
DESCRIPTION
The 545RFE automatic transmission is a sophisti-
cated, multi-range, electronically controlled transmis-
sion which combines optimized gear ratios for
responsive performance, state of the art efficiency
features and low NVH. Other features include driver
adaptive shifting and three planetary gear sets to
provide wide ratio capability with precise ratio steps
for optimum driveability. The three planetary gear
sets also make available a unique alternate second
gear ratio. The primary 2nd gear ratio fits between
1st and 3rd gears for normal through-gear accelera-
tions. The alternate second gear ratio (2prime) allows
smoother 4-2 kickdowns at high speeds to provide
2nd gear passing performance over a wider highway
cruising range. An additional overdrive ratio (0.67:1)
is also provided for greater fuel economy and less
NVH at highway speeds.The hydraulic portion of the transmission consists
of the transmission fluid, fluid passages, hydraulic
valves, and various line pressure control components.
The primary mechanical components of the trans-
mission consist of the following:
²Three multiple disc input clutches
²Three multiple disc holding clutches
²Five hydraulic accumulators
²Three planetary gear sets
²Dual Stage Hydraulic oil pump
²Valve body
²Solenoid pack
The TCM is the ªheartº or ªbrainº of the electronic
control system and relies on information from vari-
ous direct and indirect inputs (sensors, switches, etc.)
to determine driver demand and vehicle operating
conditions. With this information, the TCM can cal-
culate and perform timely and quality shifts through
various output or control devices (solenoid pack,
transmission control relay, etc.).
21 - 178 AUTOMATIC TRANSMISSION - 545RFEWJ

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Depress locking tab and unplug the wire har-
ness connector from the blower motor controller.
(3) Depress locking tab and unplug the controller
connector from the blower motor.
(4) Remove the 2 screws that secure the blower
motor controller to the HVAC housing.
(5) Remove the blower motor controller from the
HVAC housing (Fig. 15).
INSTALLATION
(1) Install the blower motor controller in the
HVAC housing. The housing is indexed to allow con-
troller mounting in only one position. Tighten the
mounting screws to 2.2 N´m (20 in. lbs.).
(2) Plug in the wire harness connector to the
blower motor controller.
(3) Plug in the connector from the blower motor
controller to the blower motor.
(4) Connect the battery negative cable.
BLOWER MOTOR RESISTOR
BLOCK
DESCRIPTION
Models with the standard manual temperature
control system have a blower motor resistor. The
blower motor resistor is mounted to the bottom of the
HVAC housing, under the instrument panel and just
inboard of the blower motor. It can be accessed for
service without removing any other components.
OPERATION
The resistor has multiple resistor wires, each of
which will reduce the current flow to the blower
motor to change the blower motor speed by changing
the resistance in the blower motor ground path. The
blower motor switch directs the ground path through
the correct resistor wire to obtain the selected speed.
With the blower motor switch in the lowest speed
position, the ground path for the motor is applied
through all of the resistor wires. Each higher speed
selected with the blower motor switch applies the
blower motor ground path through fewer of the resis-
tor wires, increasing the blower motor speed. When
the blower motor switch is in the highest speed posi-
tion, the blower motor resistor is bypassed and the
blower motor receives a direct path to ground.
The blower motor resistor cannot be repaired and,
if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR BLOCK
For circuit descriptions and diagrams, refer to the
appropriate wiring information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the
blower motor resistor.
Fig. 15 BLOWER MOTOR CONTROLLER REMOVE/
INSTALL
1 - BLOWER MOTOR CONTROLLER
2 - BLOWER MOTOR
3 - GROUND STRAP
4 - ELECTRICAL CONNECTORS
5 - HEATER CORE TUBES
WJCONTROLS 24 - 27
BLOWER MOTOR CONTROLLER (Continued)

(M)Malfunction Indicator Lamp (MIL) illuminated during engine operation if this DTC was recorded
(depending if required by CARB and/or EPA). MIL is displayed as an engine icon on instrument panel.
(G)Generator lamp illuminated
Generic Scan
Tool P-CodeDRB Scan Tool Display Brief Description of DTC
P0219 Crankshaft Position Sensor
Overspeed SignalEngine has exceeded rpm limits.
P0222 (M) Idle Validation Signals Both Low Problem detected with idle validation circuits within APPS.
P0223 (M) Idle Validation Signals Both High
(Above 5 Volts)Problem detected with idle validation circuits within APPS.
P0230 Transfer Pump (Lift Pump) Circuit
Out of RangeProblem detected in fuel transfer pump circuits.
P0232 Fuel Shutoff Signal Voltage Too High Fuel shut-off signal voltage too high from ECM to fuel
injection pump.
P0234 (M) Turbo Boost Limit Exceeded Problem detected in turbocharger wastegate.
P0236 (M) Map Sensor Too High Too Long Problem detected in turbocharger wastegate.
P0237 (M) Map Sensor Voltage Too Low MAP sensor voltage input below the minimum acceptable
voltage.
P0238 (M) Map Sensor Voltage Too High MAP sensor voltage input above the maximum
acceptable voltage.
PO243 Wastegate Solenoid Circuit
P0251 (M) Fuel Inj. Pump Mech. Failure Fuel
Valve Feedback CircuitProblem sensed with fuel circuit internal to fuel injection
pump.
P0253 (M) Fuel Injection Pump Fuel Valve
Open CircuitProblem sensed with fuel circuit internal to fuel injection
pump.
P0254 Fuel Injection Pump Fuel Valve
Current Too HighProblem caused by internal fuel injection pump failure.
P0300 (M) Multiple Cylinder Mis-fire Misfire detected in multiple cylinders.
P0301 (M) CYLINDER #1 MISFIRE Misfire detected in cylinder #1.
P0302 (M) CYLINDER #2 MISFIRE Misfire detected in cylinder #2.
P0303 (M) CYLINDER #3 MISFIRE Misfire detected in cylinder #3.
P0304 (M) CYLINDER #4 MISFIRE Misfire detected in cylinder #4.
P0305 (M) CYLINDER #5 MISFIRE Misfire detected in cylinder #5.
P0306 (M) CYLINDER #6 MISFIRE Misfire detected in cylinder #6.
P0307 (M) CYLINDER #7 MISFIRE Misfire detected in cylinder #7
P0308 (M) CYLINDER #8 MISFIRE Misfire detected in cylinder #8.
P0309 (M) CYLINDER #9 MISFIRE Misfire detected in cylinder #9.
P0310 (M) CYLINDER #10 MISFIRE Misfire detected in cylinder #10.
P0320 (M) No Crank Referance Signal at PCM No reference signal (crankshaft position sensor) detected
during engine cranking.
P0320 (M) No RPM Signal to PCM (Crankshaft
Position Sensor Signal to JTEC)A CKP signal has not been detected at the PCM.
P0325 Knock Sensor #1 Circuit Knock sensor (#1) signal above or below minimum
acceptable threshold voltage at particular engine speeds.
P0330 Knock Sensor #2 Circuit Knock sensor (#2) signal above or below minimum
acceptable threshold voltage at particular engine speeds.
25 - 6 EMISSIONS CONTROLWJ
EMISSIONS CONTROL (Continued)

set a temporary fault without turning on the MIL
and continue the leak portion of the test. However,
the PCM will assume that the system is already
pressurized and skip the rapid pump cycles.
Always diagnose leaks, if possible, before discon-
necting connections. Disconnecting connections may
mask a leak condition.
Keep in mind that if the purge solenoid seat is
leaking, it could go undetected since the leak would
end up in the intake manifold. Disconnect the purge
solenoid at the manifold when leak checking. In addi-
tion, a pinched hose fault (P1486) could set if the
purge solenoid does not purge the fuel system prop-
erly (blocked seat). The purge solenoid must vent the
fuel system prior to the LDP system test. If the
purge solenoid cannot properly vent the system the
LDP cannot properly complete the test for P1486 and
this fault can set due to pressure being in the EVAP
system during the test sequence.
Multiple actuation's of the DRB IIItLeak Detec-
tion Pump (LDP) Monitor Test can hide a 0.020 leak
because of excess vapor generation. Additionally, any
source for additional vapor generation can hide a
small leak in the EVAP system. Excess vapor gener-
ation can delay the fall of the LDP diaphragm thus
hiding the small leak. An example of this condition
could be bringing a cold vehicle into a warm shop for
testing or high ambient temperatures.
Fully plugged and partially plugged underhood
vacuum lines have been known to set MIL condi-
tions. P1494 and P0456 can be set for this reason.
Always, thoroughly, check plumbing for pinches or
blockage before condemning components.
TEST EQUIPMENT The Evaporative Emission
Leak Detector (EELD) Miller Special Tool 8404 is
capable of visually detecting leaks in the evaporative
system and will take the place of the ultrasonic leak
detector 6917A. The EELD utilizes shop air and a
smoke generator to visually detect leaks down to
0.020 or smaller. The food grade oil used to make the
smoke includes an UV trace dye that will leave tell-
tale signs of the leak under a black light. This is
helpful when components have to be removed to
determine the exact leak location. For detailed test
instructions, follow the operators manual packaged
with the EELD.
NOTE: Be sure that the PCM has the latest software
update. Reprogram as indicated by any applicable
Technical Service Bulletin. After LDP repairs are
completed, verify the repair by running the DRB IIIT
Leak Detection Pump (LDP) Monitor Test as
described in Technical Service Bulletin 18-12-99.REMOVAL
The Leak Detection Pump (LDP) is located under
the left quarter panel behind the left/rear wheel (Fig.
16). It is attached to a two-piece support bracket
(Fig. 17). The LDP and LDP filter are replaced (ser-
viced) as one unit.
(1) Remove stone shield behind left/rear wheel
(Fig. 18). Drill out plastic rivets for removal.
(2) Remove 3 LDP mounting bolts (Fig. 19).
(3) Remove support bracket brace bolt (Fig. 17).
(4) Loosen, but do not remove 2 support bracket
nuts at frame rail (Fig. 19).
(5) To separate and lower front section of two-piece
support bracket, remove 3 attaching bolts on bottom
of support bracket (Fig. 17). While lowering support
bracket, disconnect LDP wiring clip (Fig. 20).
(6) Disconnect electrical connector at LDP (Fig.
20).
(7) Carefully remove vapor/vacuum lines at LDP
(Fig. 20).
(8) Remove LDP.
INSTALLATION
The LDP is located in the left quarter panel behind
the left/rear wheel. It is attached to a two-piece sup-
port bracket (Fig. 17). The LDP and LDP filter are
replaced (serviced) as one unit.
(1) Position LDP and carefully install vapor/vac-
uum lines to LDP and LDP filter.The vapor/vac-
uum lines and hoses must be firmly connected.
Fig. 16 LOCATION, LDP / EVAP CANISTER
1 - LEAK DETECTION PUMP
2 - EVAP CANISTER
WJEVAPORATIVE EMISSIONS 25 - 35
LEAK DETECTION PUMP (Continued)