1995 JEEP CHEROKEE steering

INSTALLATION
(1) Install the muffler onto the catalytic converter
outlet. Ensure that the locator on the converter
aligns with the notch on the muffler, if so equipped.
Install the clamp and tighten the nuts finger tight.
(2) Install the exhaust tailpipe into the muffler
outlet. Ensure that the locator on the exhaust
tailpipe aligns with the notch on the muffler, if so
equipped. Install the clamp and tighten the nuts fin-
ger tight.
(3) Install the front exhaust tailpipe supports and
the rear exhaust tailpipe hanger. Ensure that the ex-
haust tailpipe has sufficient clearance from the floor
pan and shields.
(4) Tighten the nuts on the muffler-to-catalytic
converter and the muffler-to-exhaust tailpipe clamps
to 61 Nzm (45 ft. lbs.) torque.
(5) Lower the vehicle.
(6) Start the engine and inspect for exhaust leaks
and contact with the body panels and shields.
ENGINE EXHAUST MANIFOLDÐ2.5L ENGINE
REMOVAL
(1) Disconnect the battery negative cable.
(2) Remove all components attached to the intake
manifold.
(3) Raise the vehicle.
(4) Disconnect the exhaust pipe from the engine
exhaust manifold.
(5) Lower the vehicle.
(6) Remove fasteners 2 through 5 and remove the
intake manifold (Fig. 11).
(7) Remove fasteners 1, 6 and 7 and remove the
engine exhaust manifold (Fig. 11).
CLEANING
Clean the intake and engine exhaust manifolds and
cylinder head mating surfaces.DO NOT allow for-eign material to enter either the intake mani-
fold or the ports in the cylinder head.
INSTALLATION
(1) Install a new intake manifold gasket over the
alignment dowels on the cylinder head.
(2) Install the engine exhaust manifold assembly.
Exhaust manifold must be centrally located
over the end studs and spacer (Fig. 11).
(3) Tighten bolt No.1 to 41 Nzm (30 ft. lbs.) torque
(Fig. 11).
(4) Install the intake manifold on the cylinder
head dowels (Fig. 11).
(5) Install bolts 2 through 5 (Fig. 11). Tighten
these bolts to 31 Nzm (23 ft. lbs.) torque.
(6) Install new engine exhaust manifold spacers
over the engine exhaust manifold mounting studs in
the cylinder head (Fig. 11).
(7) Tighten nuts 6 and 7 to 31 Nzm (23 ft. lbs.)
torque (Fig. 11).
(8) Install all components to the intake manifold.
(9) Raise the vehicle.
(10) Connect the exhaust pipe to the engine ex-
haust manifold. Tighten the bolts to 31 Nzm (23 ft.
lbs.) torque.
(11) Lower the vehicle.
(12) Connect the battery negative cable.
(13) Start the engine and check for leaks.
ENGINE EXHAUST MANIFOLDÐ4.0L ENGINE
The intake and engine exhaust manifolds on the
4.0L engine must be removed and installed together.
The manifolds use a common gasket at the cylinder
head.
Refer to Intake ManifoldÐ4.0L Engine in this sec-
tion for the proper removal and installation proce-
dures.
INTAKE MANIFOLDÐ2.5L ENGINE
REMOVAL
(1) Disconnect the battery negative cable.
(2) Remove the air inlet hose from the throttle
body and air cleaner.
(3) Loosen the accessory drive belt tension and re-
move the belt from the power steering pump.
(4) Remove the power steering pump and brackets
from the water pump and intake manifold. Support
power steering pump and bracket with mechanics
wire attached to the radiator upper crossmember.
(5) Remove the fuel tank filler cap to relieve the
fuel tank pressure.
(6) Install the fuel tank filler cap.
(7) Disconnect fuel supply and return tube from
the fuel rail (refer to Group 14, Fuel System - Quick
Connect Fittings).
(8) Disconnect the accelerator cable from the throt-
tle body and the holddown bracket.
Fig. 11 Intake/Engine Exhaust Manifold Installation
(2.5L Engine)
JEXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 7

CAUTION: When disconnecting the cruise control
connector at the throttle body, DO NOT pry the con-
nector off with pliers or screwdriver. Use finger
pressure only. Prying the connector off could break
it.
(9) Disconnect the electrical connectors. Pull the
harnesses away from the manifold.
²The throttle position sensor.
²The idle speed control motor.
²The coolant temperature sensor at the thermostat.
²The manifold air temperature sensor at the intake
manifold.
²The fuel injectors.
²The oxygen sensor.
(10) Disconnect the crankcase ventilation (CCV)
vacuum hose and manifold absolute pressure (MAP)
sensor vacuum hose connector at the intake mani-
fold.
(11) Disconnect vacuum hose from vacuum port on
the intake manifold.
(12) Disconnect CCV hose at the cylinder head
cover (Fig. 12).
(13) Remove the molded vacuum harness.
(14) Disconnect the vacuum brake booster hose at
the intake manifold.
(15) Remove bolts 2 through 5 securing the intake
manifold to the cylinder head (Fig. 11). Slightly
loosen bolt No.1 and nuts 6 and 7.
(16) Remove the intake manifold and gaskets.
Drain the coolant from the manifold.
CLEANING
Clean the intake manifold and cylinder head mat-
ing surfaces.DO NOT allow foreign material to
enter either the intake manifold or the ports in
the cylinder head.
INSTALLATION
(1) Install the new intake manifold gasket over the
locating dowels.
(2) Position the manifold in place and finger
tighten the mounting bolts.
(3) Tighten the fasteners in sequence and to the
specified torque (Fig. 11).
²Fastener No.1ÐTighten to 41 Nzm (30 ft. lbs.)
torque.
²Fasteners Nos.2 through 7ÐTighten to 31 Nzm (23
ft. lbs.) torque.
(4) Connect the fuel return and supply tube to the
connector next to the fuel rail. Push them into the
fitting until a click is heard. Verify that the connec-
tions are complete.
²First, ensure only the retainer tabs protrude from
the connectors.
²Second, pull out on the fuel tubes to ensure they
are locked in place.
(5) Connect the molded vacuum hoses to the vac-
uum port on the intake manifold and the cylinder
head cover.
(6) Connect the electrical connectors.
²The throttle position sensor.
²The automatic idle speed control motor.
²The coolant temperature sensor at the thermostat
housing.
²The fuel injectors.
²The air manifold temperature sensor.
²The oxygen sensor.
(7) Connect the CCV vacuum hose and MAP sen-
sor vacuum hose connectors to the throttle body.
(8) Install the power steering pump and bracket
assembly to the water pump and intake manifold.
(9) Connect the accelerator cable and cruise control
cable to the holddown bracket and the throttle arm.
CAUTION: Ensure that the accessory drive belt is
routed correctly. Failure to do so can cause the wa-
ter pump to turn in the opposite direction resulting
in engine overheating. Refer to Group 7, Cooling
System for the proper procedure.
(10) Tension the accessory drive belt. Refer to
Group 7, Cooling System for the proper procedure.
(11) Connect the air inlet hose to the throttle body
and the air cleaner.
(12) Connect the battery negative cable.
(13) Start the engine and check for leaks.
INTAKE MANIFOLDÐ4.0L ENGINE
The intake and engine exhaust manifolds on the
4.0L engine must be removed and installed together.
The two manifolds use a common gasket at the cyl-
inder head.
REMOVAL
(1) Disconnect the battery negative cable.
Fig. 12 Crankcase Ventilation (CCV) Hose (2.5L
Engine)
11 - 8 EXHAUST SYSTEM AND INTAKE MANIFOLDJ

(2) Remove air cleaner inlet hose from throttle
plate assembly.
(3) Remove the air cleaner assembly.
(4) Remove the throttle cable, cruise control cable
(if equipped) and the transmission line pressure ca-
ble.
(5) Disconnect all electrical connectors on the in-
take manifold.
(6) Disconnect and remove the fuel supply and re-
turn lines from the fuel rail assembly (refer to Group
14, Fuel System).
(7) Loosen the accessory drive belt (refer to Group
7, Cooling System). Loosen the tensioner.
(8) Remove the power steering pump and bracket
from the intake manifold and set aside.
(9) Remove the fuel rail and injectors (refer to
Group 14, Fuel System).
(10) Raise the vehicle.
(11) Disconnect the exhaust pipe from the engine
exhaust manifold. Discard the seal.
(12) Lower the vehicle.
(13) Remove the intake manifold and engine ex-
haust manifold.
CLEANING
Clean the mating surfaces of the cylinder head and
the manifold if the original manifold is to be in-
stalled.
If the manifold is being replaced, ensure all the fit-
ting, etc. are transferred to the replacement mani-
fold.
INSTALLATION
(1) Install a new exhaust/intake manifold gasket
over the alignment dowels on the cylinder head.
(2) Position the engine exhaust manifold to the cyl-
inder head. Install fastener No.3 and finger tighten
at this time (Fig. 13).
(3) Install intake manifold on the cylinder head
dowels.
(4) Install washers and fasteners Nos.1, 2, 4, 5, 8,
9, 10 and 11 (Fig. 13).
(5) Install washers and fasteners Nos.6 and 7 (Fig.
13).
(6) Tighten the fasteners in sequence and to the
specified torque (Fig. 13).
²Fasteners Nos.1 through 5ÐTighten to 33 Nzm (24
ft. lbs.) torque.
²Fasteners Nos.6 and 7ÐTighten to 31 Nzm (23 ft.
lbs.) torque.²Fasteners Nos.8 through 11ÐTighten to 33 Nzm
(24 ft. lbs.) torque.
(7) Install the fuel rail and injectors.
(8) Install the power steering pump and bracket to
the intake manifold. Tighten the belt to specification.
Refer to Group 7, Cooling System for the proper pro-
cedures.
(9) Install the fuel supply and return lines to the
fuel rail assembly.Before connecting the fuel
lines to the fuel rail replace the O-rings in the
quick-connect fuel line couplings.Refer to Group
14, Fuel System for the proper procedure.
(10) Connect all electrical connections on the in-
take manifold.
(11) Connect the vacuum connector on the intake
manifold and install it in the bracket.
(12) Install throttle cable, cruise control cable (if
equipped).
(13) Install the transmission line pressure cable (if
equipped). Refer to Group 21, Transmission for the
adjustment procedures.
(14) Install air cleaner assembly.
(15) Connect air inlet hose to the throttle plate as-
sembly.
(16) Raise the vehicle on a side mounted hoist.
(17) Using a new seal, connect the exhaust pipe to
the engine exhaust manifold. Tighten the bolts to 31
Nzm (23 ft. lbs.) torque.
(18) Lower the vehicle.
(19) Connect the battery negative cable.
(20) Start the engine and check for leaks.
Fig. 13 Intake/Engine Exhaust Manifold Installation
(4.0L Engine)
JEXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 9

The retaining screws and the steering gear
skid plate must be removed before the left
strap can be removed from the sillmember.
(5) Detach the tow hook straps from the sillmem-
ber.
(6) Support the bumper.
(7) Remove the bolts that attach the bumper sup-
port brackets to the right and left sillmembers (Fig.
5).
(8) Remove the support and the bumper from the
vehicle (Fig. 5).
(9) Remove the nuts and bolts that attach the tow
hooks to the bumper support brackets.
(10) Remove the support brackets (Fig. 6), bumper
guards (Fig. 7) and caps (Fig. 8) from the bumper
rail.(11) Remove the license plate bracket (Fig. 9), if
equipped, from the bumper rail.
Fig. 5 Front Bumper Removal/Installation
Fig. 6 Bumper Support Bracket Removal/Installation
Fig. 7 Bumper Guard Removal/Installation
Fig. 8 Bumper End Cap Removal/Installation
Fig. 9 Bumper License Plate Bracket Removal/
Installation
13 - 6 XJÐBUMPERSJ

(12) Remove the fog lamps (Fig. 10) from the
bumper rail.
(13) If necessary, remove the vacuum reservoir(s)
from the bumper rail.
(14) If necessary, remove the sill crossmember re-
inforcement brackets from the sillmembers.
ASSEMBLY/INSTALLATION
(1) If removed, install the sill crossmember rein-
forcement brackets on the sillmembers (Fig. 11).
Tighten bolts to 56 Nzm (41 ft. lbs.) torque.
(2) If equipped, install the bumper support brack-
ets and bumper guards on the bumper rail. Tighten
hardware in the sequence indicated in (Fig. 6).
Tighten the locknuts with 20 Nzm (15 ft. lbs.) torque.
Tighten bolts to 56 Nzm (41 ft. lbs.) torque.
(3) If not equipped with bumper guards, install the
bumper support brackets on the bumper rail. Tighten
bolts to 56 Nzm (41 ft. lbs.) torque.
(4) Install tow hooks. Tighten nuts with 100 Nzm
(74 ft. lbs.) torque.
(5) Install the bumper end caps on the bumper
rail. Tighten nuts with 8 Nzm (72 in. lbs.) torque.(6) Install the license plate bracket on the bumper
rail. Tighten the nuts securely.
(7) Install the fog lamps on the bumper rail.
Tighten the nuts to 20 Nzm (15 ft. lbs.) torque.
(8) If removed, install the vacuum reservoir(s) on
the bumper rail. Tighten the retaining screws and
bolts to 8 Nzm (72 in. lbs.) torque.
(9) Position and support the bumper at the front of
the vehicle.
(10) Attach the bumper support brackets to the
right and left sillmembers and reinforcement brack-
ets. Tighten screws and bolts to 56 Nzm (41 ft. lbs.)
torque.
(11) Install the Torx-head bolts and locknuts that
attach the tow hook straps to the underbody sillmem-
ber. Tighten locknuts with 30 Nzm (22 ft. lbs.) torque.
Install the steering gear skid plate and screws
after the left tow hook strap has been installed.
(12) Connect the fog lamp wire harness connectors.
(13) Connect the vacuum reservoir tube harness
connectors.
(14) Remove the bumper support.
FRONT TOW HOOKS
If a tow hook must be replaced or removed only for
service access, remove the nuts and bolts that attach
it to the bumper support bracket. When installing a
tow hook, tighten nuts with 100 Nzm (74 ft. lbs.)
torque.
If a tow hook/bumper support bracket must be re-
placed, refer to the following removal and installation
procedures.
REMOVAL
If equipped with a brush guard, refer to the Brush
Guard Removal within Group 23, Body Components.
(1) Disconnect the fog lamp wire harness connec-
tors, if equipped.
(2) Disconnect the vacuum reservoir tube harness
connectors.
(3) Support the bumper.
(4) Remove the bolts that attach the bumper sup-
port brackets to the right and left sillmembers.
(5) Remove the locknuts and Torx-head bolts that
attach the tow hook straps to the underbody sillmem-
ber.
The retaining screws and the steering gear
skid plate must be removed before the left
strap can be removed from the sillmember.
(6) Detach the tow hook straps from the sillmem-
ber.
(7) Remove the support and the bumper from the
vehicle.
(8) Remove the nuts and bolts that attach the tow
hooks to the bumper support brackets.
(9) Remove the tow hook from the bumper support
bracket.
Fig. 10 Fog Lamp
Fig. 11 Reinforcement Brackets
JXJÐBUMPERS 13 - 7

(10) Remove the support bracket from the bumper
rail.
INSTALLATION
(1) Install the bumper guard and bumper support
bracket on the bumper rail. Tighten the retaining
hardware in the sequence indicated in Figure 7.
Tighten locknuts to 20 Nzm (15 ft. lbs.) torque.
Tighten bolts to 56 Nzm (41 ft. lbs.) torque.
(2) If not equipped with bumper guards, install the
bumper support bracket on the bumper rail. Tighten
bolts to 56 Nzm (41 ft. lbs.) torque.
(3) Position the tow hook at the support bracket.
Install the bolts and nuts that attach tow hook to the
bumper support bracket. Tighten nuts to 100 Nzm (74
ft. lbs.) torque.
(4) Position and support the bumper at the front of
the vehicle.
(5) Attach the bumper support brackets to the
right and left sillmembers and reinforcement brack-
ets. Tighten screws and bolts to 56 Nzm (41 ft. lbs.)
torque.
(6) Install the Torx-head bolts and locknuts that
attach the tow hook straps to the underbody sillmem-
ber. Tighten locknuts to 30 Nzm (22 ft. lbs.) torque.
Install the steering gear skid plate and screws
after the left tow hook strap has been installed.
(7) Connect the fog lamp wire harness connectors.
Connect the vacuum reservoir tube harness connec-
tors.
(8) Remove the bumper support.
REAR BUMPER
REMOVAL
(1) For vehicles equipped with a trailer hitch, re-
move the hitch before removing the bumper. If neces-
sary, refer to the removal procedure within Group 23,
Body Components.
(2) Raise and support the rear of the vehicle.
(3) Support the bumper.
(4) Remove the bolts that attach the bumper sup-
port brackets to the sill crossmember (Fig. 12).
(5) Remove the support and the rear bumper from
the vehicle.
(6) Remove the bumper support brackets and
splash shield the bumper, if necessary (Fig. 13).
(7) Remove the bumper end caps (Fig. 14) and
bumper guards from the bumper (Fig. 15), if neces-
sary.
INSTALLATION
(1) As applicable, install the splash shield and
bumper support brackets, the bumper end caps and
the bumper guards.
(2) Tighten the bumper support bolts to 56 Nzm (41
ft. lbs.).(3) Tighten the nuts in the sequence depicted in
Figure 14. Tighten the bumper end cap plate bolt
Fig. 12 Rear Bumper Removal/InstallationÐXJ
Vehicles
Fig. 13 Bumper Bracket & Splash Shield Removal/
InstallationÐXJ Vehicles
Fig. 14 Bumper End Cap Removal/InstallationÐXJ
Vehicles
13 - 8 XJÐBUMPERSJ

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

The MAP sensor is mounted on the dash panel.
The sensor is connected to the throttle body with a
vacuum hose and to the PCM electrically.
OXYGEN (O2S) SENSORÐPCM INPUT
The O2S sensor is located in the exhaust down pipe
(Fig. 11). It provides an input voltage to the power-
train control module (PCM) relating the oxygen con-
tent of the exhaust gas. The PCM uses this
information to fine tune the air-fuel ratio by adjust-
ing injector pulse width.
The O2S sensor produces voltages from 0 to 1 volt.
This voltage will depend upon the oxygen content of
the exhaust gas in the exhaust manifold. When a
large amount of oxygen is present (caused by a lean
air-fuel mixture), the sensor produces a low voltage.
When there is a lesser amount present (rich air-fuel
mixture) it produces a higher voltage. By monitoring
the oxygen content and converting it to electrical
voltage, the sensor acts as a rich-lean switch.
The oxygen sensor is equipped with a heating ele-
ment that keeps the sensor at proper operating tem-
perature during all operating modes. Maintaining
correct sensor temperature at all times allows the
system to enter into closed loop operation sooner.
In Closed Loop operation, the powertrain control
module (PCM) monitors the O2S sensor input (along
with other inputs). It then adjusts the injector pulse
width accordingly. During Open Loop operation, the
PCM ignores the O2S sensor input and adjusts injec-
tor pulse width to a preprogrammed value (based on
other sensor inputs).
PARK/NEUTRAL SWITCHÐPCM INPUT
The park/neutral switch is located on the transmis-
sion housing and provides an input to the powertrain
control module (PCM). This will indicate that the au-
tomatic transmission is in Park, Neutral or a drive
gear selection. This input is used to determine idle
speed (varying with gear selection), fuel injector
pulse width, ignition timing advance and vehiclespeed control operation. Refer to Group 21, Transmis-
sions, for testing, replacement and adjustment infor-
mation.
POWER GROUND
The power ground is used to control ground circuits
for the following powertrain control module (PCM)
loads:
²Generator Field Winding
²8 volt (PCM) power supply
²Fuel Injectors
²Ignition Coil
POWER STEERING PRESSURE SWITCHÐPCM
INPUT
A pressure sensing switch is included in the power
steering system (mounted on the high-pressure line).
This switch will be on vehicles equipped with a 2.5L
engine and power steering. The switch (figure 12, YJ
models or figure 13, XJ models) provides an input to
the PCM. This input is provided during periods of
high pump load and low engine rpm; such as during
parking maneuvers. The PCM will then increase the
idle speed through the idle air control (IAC) motor.
This is done to prevent the engine from stalling un-
der the increased load.
When steering pump pressure exceeds 1896 kPa6
172 kPa (275625 psi) the PCM will increase the en-
gine idle speed. This will prevent the engine from
stalling.
SCI RECEIVEÐPCM INPUT
SCI Receive is the serial data communication re-
ceive circuit for the DRB scan tool. The powertrain
control module (PCM) receives data from the DRB
through the SCI Receive circuit.
Fig. 11 Heated Oxygen Sensor LocationÐTypicalFig. 12 Power Steering Pump Pressure SwitchÐYJ
Models
14 - 24 FUEL SYSTEM COMPONENT DESCRIPTION/SYSTEM OPERATIONJ