1995 JEEP CHEROKEE key battery

MULTI-PORT FUEL INJECTION (MFI)ÐCOMPONENT DESCRIPTION/SYSTEM
OPERATION
INDEX
page page
Air Cleaner.............................. 29
Air Conditioning (A/C) Clutch RelayÐPCM Output . 26
Air Conditioning (A/C) ControlsÐPCM Input...... 21
Auto Shutdown (ASD) RelayÐPCM Output...... 26
Automatic Shutdown (ASD) SenseÐPCM Input . . . 21
Battery VoltageÐPCM Input................. 21
Brake SwitchÐPCM Input................... 22
Camshaft Position SensorÐPCM Input......... 22
Crankshaft Position SensorÐPCM Input........ 22
Data Link ConnectorÐPCM Input............. 22
Data Link ConnectorÐPCM Output............ 27
EMR LampÐPCM Output................... 27
Engine Coolant Temperature SensorÐPCM Input . 23
Extended Idle SwitchÐPCM Input............. 23
Fuel InjectorsÐPCM Output................. 27
Fuel Pressure Regulator.................... 33
Fuel Pump RelayÐPCM Output.............. 27
Fuel Rail................................ 33
General Information....................... 19
Generator FieldÐPCM Output................ 27
Generator LampÐPCM Output............... 27
Idle Air Control (IAC) MotorÐPCM Output....... 27
Ignition Circuit SenseÐPCM Input............. 23
Ignition CoilÐPCM Output................... 28Intake Manifold Air Temperature SensorÐ
PCM Input............................. 22
Malfunction Indicator LampÐPCM Output....... 28
Manifold Absolute Pressure (MAP) SensorÐPCM
Input................................. 23
Open Loop/Closed Loop Modes of Operation..... 30
Oxygen (O2S) SensorÐPCM Input............ 24
Park/Neutral SwitchÐPCM Input.............. 24
Power Ground........................... 24
Power Steering Pressure SwitchÐPCM Input.... 24
Powertrain Control Module (PCM)............. 20
Radiator Fan RelayÐPCM Output............. 28
SCI ReceiveÐPCM Input................... 24
SCI TransmitÐPCM Output.................. 29
Sensor ReturnÐPCM Input.................. 25
Shift IndicatorÐPCM Output................. 29
Speed ControlÐPCM Input.................. 25
Speed ControlÐPCM Output................. 29
TachometerÐPCM Output................... 29
Throttle Body............................ 33
Throttle Position Sensor (TPS)ÐPCM Input...... 25
Torque Converter Clutch RelayÐPCM Output.... 29
Vehicle Speed SensorÐPCM Input............ 25
GENERAL INFORMATION
All 2.5L 4-cylinder and 4.0L 6-cylinder engines are
equipped with sequential Multi-Port Fuel Injection
(MFI). The MFI system provides precise air/fuel ra-
tios for all driving conditions.
The Powertrain Control Module (PCM) operates
the fuel system. The PCM was formerly referred to
as the SBEC or engine controller. The PCM is a pre-
programmed, dual microprocessor digital computer. It
regulates ignition timing, air-fuel ratio, emission con-
trol devices, charging system, speed control, air con-
ditioning compressor clutch engagement and idle
speed. The PCM can adapt its programming to meet
changing operating conditions.
Powertrain Control Module (PCM) Inputsrep-
resent the instantaneous engine operating conditions.
Air-fuel mixture and ignition timing calibrations for
various driving and atmospheric conditions are pre-
programmed into the PCM. The PCM monitors and
analyzes various inputs. It then computes engine fuel
and ignition timing requirements based on these in-
puts. Fuel delivery control and ignition timing will
then be adjusted accordingly.
Other inputs to the PCM are provided by the brake
light switch, air conditioning select switch and the
speed control switches. All inputs to the PCM are
converted into signals.
Electrically operated fuel injectors spray fuel inprecise metered amounts into the intake port directly
above the intake valve. The injectors are fired in a
specific sequence by the PCM. The PCM maintains
an air/fuel ratio of 14.7 to 1 by constantly adjusting
injector pulse width. Injector pulse width is the
length of time that the injector opens and sprays fuel
into the chamber. The PCM adjusts injector pulse
width by opening and closing the ground path to the
injector.
Manifold absolute pressure (air density) and engine
rpm (speed) are the primary inputs that determine
fuel injector pulse width. The PCM also monitors
other inputs when adjusting air-fuel ratio.
Inputs That Effect Fuel Injector Pulse Width:
²Exhaust gas oxygen content
²Engine coolant temperature
²Manifold absolute pressure (MAP)
²Engine speed
²Throttle position
²Battery voltage
²Air conditioning selection
²Transmission gear selection (automatic transmis-
sions only)
²Speed control
The powertrain control module (PCM) adjusts igni-
tion timing by controlling ignition coil operation. The
ignition coil receives battery voltage when the igni-
tion key is in the run or starter position. The PCM
JFUEL SYSTEM COMPONENT DESCRIPTION/SYSTEM OPERATION 14 - 19

EXAMPLES:
²If the lamp (Figs. 45 or 46) flashes 1 time, pauses
and flashes 2 more times, a flashing Diagnostic Trou-
ble Code (DTC) number 12 is indicated. If this code is
observed, it is indicating that the battery has been
disconnected within the last 50 key-on cycles. It
could also indicate that battery voltage has been dis-
connected to the PCM. In either case, other DTC's
may have been erased.
²If the lamp flashes 4 times, pauses and flashes 1
more time, a flashing Diagnostic Trouble Code (DTC)
number 41 is indicated.
²If the lamp flashes 4 times, pauses and flashes 6
more times, a flashing Diagnostic Trouble Code
(DTC) number 46 is indicated.
After any stored DTC information has been ob-
served, the display will end with a flashing DTC
number 55. This will indicate the end of all stored in-
formation.
Refer to the Diagnostic Trouble Code (DTC) charts
for DTC identification.If the problem is repaired or ceases to exist, the
Powertrain Control Module (PCM) cancels the DTC
after 51 engine starts.
Diagnostic Trouble Codes indicate the results of a
failure, but never identify the failed component di-
rectly.
The circuits of the data link connector are shown in
(Fig. 49).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB
scan tool to erase a Diagnostic Trouble Code (DTC).
Refer to the appropriate Powertrain Diagnostic Pro-
cedures service manual for operation of the DRB
scan tool.
DRB SCAN TOOL
For operation of the DRB scan tool, refer to the ap-
propriate Powertrain Diagnostic Procedures service
manual.
DIAGNOSTIC TROUBLE CODE (DTC)
On the following pages, a list of diagnostic trouble
codes is provided for the 2.5L 4-cylinder and 4.0L
6-cylinder engines. A DTC indicates that the power-
train control module (PCM) has recognized an abnor-
mal signal in a circuit or the system. A DTC may
indicate the result of a failure, but never identify the
failed component directly.
Fig. 47 Data Link ConnectorÐYJ ModelsÐTypical
Fig. 48 Data Link ConnectorÐXJ ModelsÐTypical
Fig. 49 Data Link Connector Schematic
14 - 54 FUEL SYSTEM GENERAL DIAGNOSISJ

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
Diagnostic
Trouble CodeDRB Scan Tool Description of Diagnostic Trouble Code
11* No Crank Reference Signal at PCM No crank reference signal detected during en-
gine cranking.
12* Battery Disconnect Direct battery input to PCM was disconnected
within the last 50 Key-on cycles.
13** No Change in MAP From Start to Run No difference recognized between the engine
MAP reading and the barometric (atmospheric)
pressure reading at start-up.
14** MAP Sensor Voltage Too Low MAP sensor input below minimum acceptable
voltage.
or
MAP Sensor Voltage Too High MAP sensor input above maximum acceptable
voltage.
15** No Vehicle Speed Sensor Signal No vehicle distance (speed) sensor signal de-
tected during road load conditions.
17* Engine is Cold Too Long Engine coolant temperature remains below
normal operating temperatures during vehicle
travel (thermostat).
21** O2S Stays at Center Neither rich or lean condition detected from
the oxygen sensor input.
or
O2S Shorted to Voltage Oxygen sensor input voltage maintained above
the normal operating range.
22** ECT Sensor Voltage Too High Engine coolant temperature sensor input
above maximum acceptable voltage.
or
ECT Sensor Voltage Too Low Engine coolant temperature sensor input below
minimum acceptable voltage.
23** Intake Air Temp Sensor Voltage Low Intake manifold air temperature sensor input
below the minimum acceptable voltage.
or
Intake Air Temp Sensor Voltage High Intake manifold air temperature sensor input
above the maximum acceptable voltage.
24** Throttle Position Sensor Voltage High Throttle position sensor input above the maxi-
mum acceptable voltage.
or
Throttle Position Sensor Voltage Low Throttle position sensor input below the mini-
mum acceptable voltage.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key
as described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
JFUEL SYSTEM GENERAL DIAGNOSIS 14 - 55

DIAGNOSTIC TROUBLE CODE DESCRIPTIONSÐCONTINUED
Diagnostic
Trouble CodeDRB Scan Tool Description of Diagnostic Trouble Code
44* Battery Temp Sensor Volts out of Limit An open or shorted condition exists in the en-
gine coolant temperature sensor circuit or a
problem exists in the PCM's battery tempera-
ture voltage circuit.
46** Charging System Voltage Too High Battery voltage sense input above target
charging voltage during engine operation.
47** Charging System Voltage Too Low Battery voltage sense input below target
charging during engine operation. Also, no sig-
nificant change detected in battery voltage
during active test of generator output.
51** O2S Signal Stays Below Center (Lean) Oxygen sensor signal input indicates lean air/
fuel ratio condition during engine operation.
52** O2S Signal Stays Above Center (Rich) Oxygen sensor signal input indicates rich air/
fuel ratio condition during engine operation.
53* Internal PCM Failure PCM Internal fault condition detected.
or
PCM Failure SRI Communications PCM Internal fault condition detected.
54* No Cam Sync Signal at PCM No fuel sync (camshaft signal) detected during
engine cranking.
55* Display not shown on DRB scan tool Completion of diagnostic trouble code display
on the Malfunction Indicator Lamp (Check En-
gine Lamp).
62* PCM Failure SRI miles not stored Unsuccessful attempt to update SRI (service
reminder indicator) miles in the PCM EE-
PROM.
63* PCM Failure EEPROM Write Denied Unsuccessful attempt to write to an EEPROM
location by the PCM.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle
Ignition key as described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
JFUEL SYSTEM GENERAL DIAGNOSIS 14 - 57

(7) Install wiring harness connectors onto clock
spring and ignition switch assembly (Fig. 20).
(8) Install shaft coupler pinch bolt loose, load col-
umn up to panel bracket.(9) Be sure both spacers are fully seated in the col-
umn support bracket. Tighten the column panel
bracket support nuts to 12 Nzm (105 in. lbs.) torque.
(10) Tighten the coupler pinch bolt to 47 Nzm (35
ft. lbs.) torque.
(11) Install the upper and lower shrouds. Install
the tilt lever (if equipped).
(12) Install rely box.
(13) Install the knee blocker.
(14) Install the steering wheel, refer to Steering
Wheel Installation and observe cautions.
(15) Remove the column shaft shipping lock pin
(installed in service column).
(16) Arm airbag, refer to Arming/Disarming Airbag
in this section.
(17) Connect the battery ground (negative) cable.
COLUMN COMPONENT SERVICE
The Acustar columns have been designed to be ser-
viced as an assembly; less wiring, switches, shrouds,
steering wheel, etc. Also most steering column com-
ponents can be serviced without removing the col-
umn from the vehicle. For additional information on
electrical components refer to Group 8, Electrical.
IGNITION SWITCH SERVICE
TEST AND REPAIR
If the ignition switch effort seems to be excessive
due to binding. Follow the procedure outlined below
to determine the cause.
When service procedures are performed on the
Acustar steering column there are certain areas of
the column that can not be tampered with. If a prob-
lem related to these areas of the steering column are
detected. The entire steering column (less the remov-
able components) should be replaced see (Fig. 1 and
2).
Fig. 17 Ground Clip & Spacer Installation
Fig. 18 Multi Function Switch Wiring Harness
Connector Installed
Fig. 19 Wiring Harness Connection For Key Light
Switch
Fig. 20 Wiring Harness Connection To Clock Spring
And Ignition Switch
19 - 54 STEERINGJ

(6) Column shift vehicles, install the shift cable
grommet on the shift lever.
(7) Install and tighten the toe plate to floor pan
bolts/nuts to 21.5 Nzm (192 in. lbs.) torque (Fig. 5).
(8) Install the lower portion of the instrument
panel, refer to Group 8E, Instrument Panel.
(9) Install steering wheel on column, refer to Steer-
ing Wheel-Installation.
(10) Connect the negative (ground) cable to the
battery.
NON-TILT STEERING COLUMN
DISASSEMBLYÐCOLUMN OR CONSOLE SHIFT
Steering column removal from the vehicle is not
necessary for;
²Lockplate cover
²Lockplate
²Steering shaft retaining ring
²Canceling cam
²Turn signal switch
²Upper bearing preload spring
²Ignition key/lock cylinder service
The steering column must be removed from
the vehicle to service any other component.
(1) If the column is removed for service, fabricate a
support fixture to clamp it in a vise (Fig. 1).
(2) Remove the steering wheel. Refer to the re-
moval procedure.
(3) Remove the lockplate cover.
WARNING: THE LOCKPLATE RETAINS A VERY
STRONG, SPRING FORCE. DO NOT ATTEMPT TOREMOVE THE STEERING SHAFT RETAINING SNAP
RING WITHOUT USING LOCKPLATE COMPRESSOR
C-4156.
(4) Compress the lockplate with Compressor
C-4156 and release the steering shaft retaining snap
ring (Fig. 2).
(5) Remove the lockplate compressor tool and the
retaining snap ring. Discard the snap ring.
CAUTION: When the steering shaft retaining snap
ring is removed, the steering shaft is no longer re-
tained within the column.
(6) Remove the lockplate, canceling cam, upper
bearing preload spring, and the thrust washer from
the steering column/shaft (Fig. 3).
(7) Remove the hazard warning switch knob. Press
the knob inward and remove it from the column by
turning it counterclockwise.
(8) Remove the turn signal/wiper/cruise control
stalk by pulling it out straight from the column.
Wiper must be in the off position.
(9) Disconnect the turn signal wire harness con-
nector from the bracket.
CAUTION: Wrap tape around the turn signal
switch wire harness connector (Fig. 4) to prevent it
from becoming entangled during removal.
(10) Remove the turn signal switch retaining
screws (Fig. 5), dimmer switch actuator arm, to re-
move the switch. Guide the switch straight up and
out of the steering column.
Fig. 1 Steering Column Support Fixture
Fig. 2 Retaining Snap Ring Removal
19 - 60 STEERINGJ

(6) Position the turn signal switch and wire har-
ness in the cylinder housing. Fold the wires against
the connector. Route the connector down through the
steering column jacket.
(7) Install the windshield wiper wire harness and
switch. Route the wire harness down through steer-
ing column jacket.
(8) Align the turn signal switch in the housing and
secure the switch with the attaching screws. Tighten
the screws to 4 Nzm (35 in. lbs.) torque.
(9) Install the dimmer switch actuator arm.
Tighten the attaching screws to 4 Nzm (35 in. lbs.)
torque.
(10) If equipped, install the cruise control wire har-
ness. Install the turn signal stalk by pushing it
straight into the column.
(11) Position the thrust washer, the upper bearing
preload spring and the canceling cam on the steering
shaft (Fig. 18).
(12) Place the turn signal switch in the neutral
(OFF) position and install the hazard warning switch
knob.
(13) Position the lockplate on the steering shaft.
Install a replacement lockplate retaining snap ring
on the sleeve of the Lock Plate Compressor C-4156.
Install the tool on the steering shaft (Fig. 19).
(14) Compress the lockplate with the compressor
tool and position the retaining snap ring in the steer-
ing shaft groove.
(15) Ensure that the retaining snap ring is com-
pletely seated in the groove before removing the tool.
Remove the tool and install the lockplate cover.(16) Install the steering wheel. Refer to the instal-
lation procedure. Tighten the steering wheel retain-
ing nut to 34 Nzm (25 ft. lbs.) torque.
(17) If removed, install the steering column in the
vehicle. Refer to the installation procedure.
(18) If disconnected, connect the battery negative
cable and, if equipped, reset the clock
Fig. 17 Key/Lock Cylinder InstallationFig. 18 Canceling Cam Position
Fig. 19 Lockplate Snap Ring Installation
JSTEERING 19 - 65

TILT STEERING COLUMN
DISASSEMBLY
(1) Remove the steering column from the vehicle, if
necessary. Refer to the removal procedure.
(2) If the column is removed for service, fabricate a
support fixture to clamp it in a vise (Fig. 1).
(3) If the steering column has not been removed
from the vehicle, place the front wheels in the
straight-ahead position. Disconnect the battery nega-
tive cable.
(4) Protect the painted areas on the steering col-
umn.
(5) Remove the steering wheel. Refer to the re-
moval procedure.
(6) Column shift: Remove the gear selector lever
retaining pin and the lever from the housing.
(7) Remove the lockplate cover. Use two small pry
bars to pry the cover off the lockplate.
WARNING: THE LOCKPLATE RETAINS A VERY
STRONG, SPRING FORCE. DO NOT ATTEMPT TO
REMOVE THE STEERING SHAFT RETAINING SNAP
RING WITHOUT USING LOCKPLATE COMPRESSOR
C-4156.
(8) Compress the lockplate with Lock Plate Com-
pressor C-4156 and release the steering shaft retain-
ing snap ring (Fig. 2).
(9) Remove the lockplate compressor tool and the
retaining snap ring. Discard the snap ring.
(10) Remove the lockplate, canceling cam, upper
bearing preload spring, and the thrust washer from
the steering column/shaft.(11) Remove the hazard warning switch knob.
Press the knob inward and remove it from the steer-
ing column by turning it counterclockwise.
(12) If the steering column is the column shift
type, remove the two retaining screws and the gear
selector indicator cover.
(13) If the steering column is the column shift
type, remove the gear selector indicator lamp bracket
retaining screw. Do not remove the lamp and bracket
at this time.
(14) Remove the tilt-release lever.
(15) Disconnect the turn signal wire harness con-
nector from the bracket located at the lower end of
the steering column (Fig. 3).
CAUTION: Wrap tape around the turn signal switch
wire harness connector to prevent it from becoming
entangled during removal.
(16) Remove the plastic protector from the wire
harness.
(17) Remove the turn signal switch retaining
screws (Fig. 4), dimmer switch actuator arm, to re-
move the switch. Guide the switch straight up and
out of the steering column.
(18) Remove the windshield wiper switch wire har-
ness and all the other wire harnesses located within
the steering column.
(19) Insert the ignition switch key into the key/lock
cylinder. Turn the key to the ON position.
CAUTION: Do not attempt to remove the key warn-
ing buzzer switch and contacts separately. If sepa-
rated, the contacts can detach and drop into the
steering column.
Fig. 1 Steering Column Support Fixture
Fig. 2 Lockplate Snap Ring Removal
19 - 66 STEERINGJ