JEEP CHEROKEE 1988 Service Repair Manual

Fig. 124: Transmission Wiring Diagram (Cherokee)

Fig. 125: TCM Connector Terminals I.D., Circuits & Functions
Courtesy of Chrysler Corp.
REMOVAL & INSTALLATION
BRAKE SWITCH
Removal
Remove lower steering column cover or trim panels for access
to brake switch (if necessary). Disconnect brake switch electrical
connector. Thread brake switch from retainer and remove.

Installation
1) Install brake switch in retainer. Reconnect brake switch
electrical connector.
2) To check brake switch adjustment, slightly depress brake
pedal and note operation of brake switch plunger. Brake switch plunger
should fully extend when brake pedal free play is taken up and brake
application begins.
3) Clearance between brake switch plunger and brake pedal
should be approximately 1/8". If clearance is not within
specification, pull brake pedal rearward as far as possible.
4) Brake pedal should contact brake switch plunger, pushing
brake switch backward in retainer to provide proper adjustment. Ensure
brake lights operate.
5) Recheck clearance between brake switch plunger and brake
pedal with brake pedal depressed and free play taken up. Reinstall
lower steering column cover or trim panels.
NEUTRAL SAFETY SWITCH
NOTE: Neutral safety switch may be referred to as park/neutral or
gear select switch.
Removal
1) Apply parking brake. Raise and support vehicle. Disconnect
electrical connector at neutral safety switch. Pry lock washer tabs
away from retaining nut. See Fig. 126.
2) Remove retaining nut, lock washer and adjusting bolt. See
Fig. 126 . Remove neutral safety switch from manual valve shaft.
Installation
1) Disconnect shift control rod from transmission shift
lever. Rotate transmission shift lever fully rearward and then forward
2 detents to Neutral position.
2) Install neutral safety switch on manual valve shaft.
Install adjusting bolt but DO NOT tighten at this time.
3) Install lock washer and retaining nut. Tighten retaining
nut to specification. See TORQUE SPECIFICATIONS. DO NOT bend over lock
washer tabs at this time.
4) Ensure transmission is still in Neutral. Rotate neutral
safety switch and align neutral standard line with vertical groove on
manual valve shaft. See Fig. 126.
5) Tighten the adjusting bolt to specification. Refer to the
TORQUE SPECIFICATIONS table. Bend lock washer tabs over. Reconnect
shift control rod and electrical connector. Ensure vehicle starts in
Park and Neutral only.
Fig. 126: Installing Neutral Safety Switch
Courtesy of Chrysler Corp.
SPEED SENSOR

Removal & Installation
1) Disconnect electrical connector at speed sensor located on
adapter housing or extension housing. Remove bolt and speed sensor.
Remove "O" ring from speed sensor.
2) To install, reverse removal procedure using NEW "O" ring.
Tighten bolt to specification. See TORQUE SPECIFICATIONS at end of
article.
THROTTLE POSITION SENSOR (TPS)
Removal & Installation
1) Note location of TPS electrical connector. See Fig. 127.
Disconnect electrical connector. Remove screws and TPS.
Fig. 127: Identifying TPS Electrical Connector
Courtesy of Chrysler Corp.
2) To install, reverse removal procedure. Ensure throttle
shaft on throttle body engages socket tangs on TPS. See Fig. 128.
Tighten screws. Manually operate throttle and ensure no binding
exists. Reinstall electrical connector.
NOTE: TPS must be installed so it can be rotated a few degrees. If

TPS cannot be rotated, reinstall TPS with end of throttle
shaft on other side of TPS socket tangs.
Fig. 128: Installing Throttle Position Sensor (TPS)
Courtesy of Chrysler Corp.
TRANSMISSION CONTROL MODULE (TCM)
Removal & Installation (Cherokee)
Ensure ignition is off. Disconnect electrical connector from
TCM, located behind right side of instrument panel. See Fig. 129.
Remove fastener and TCM from instrument panel. To install, reverse
removal procedure.
Fig. 129: Transmission Control Module (TCM) I.D. (Cherokee)
Courtesy of Chrysler Corp.
VALVE BODY SOLENOID

Removal
1) Raise and support vehicle. Remove drain plug and drain
transmission fluid. Remove bolts and oil pan. Remove bolts, oil screen
and gasket.
2) Disconnect electrical connectors from valve body solenoid.
Mark electrical connector location for reassembly reference if more
than one valve body solenoid is being removed. Remove bolt, valve body
solenoid and "O" ring.
CAUTION: DO NOT allow components to fall from valve body when
removing valve body solenoid.
Installation
1) To install, reverse removal procedure using NEW "O" ring
and NEW gaskets. Tighten valve body solenoid bolt and oil screen bolt
to specification. See TORQUE SPECIFICATIONS at end of article.
2) Ensure magnet is installed in oil pan and does not
interfere with valve body oil tubes. Apply 1/8" bead of Loctite 599
sealant on oil pan mounting flange. Install oil pan. Install and
tighten bolts to specification. See TORQUE SPECIFICATIONS.
3) Install NEW gasket and drain plug. Tighten drain plug to
specification. See TORQUE SPECIFICATIONS at end of article. Fill
transmission to proper fluid level with Mopar Dexron-IIE/Mercon ATF.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS








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Application Ft. Lbs. (N.m)
Drain Plug ....................................... 15 (20)
INCH Lbs. (N.m)
Neutral Safety Switch Adjusting Bolt .......... 108 (12.2)
Neutral Safety Switch Retaining Nut ............. 61 (6.9)
Oil Pan Bolt .................................... 65 (7.3)
Oil Screen Bolt ................................. 84 (9.5)
Speed Sensor Bolt ............................... 65 (7.3)
Valve Body Solenoid Bolt ........................ 84 (9.5)









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BRAK E S YSTE M B LE ED IN G

1988 J e ep C hero ke e
1988 BRAKES
Jeep - Brake System Bleeding
Cherokee, Comanche, Grand Wagoneer, Wagoneer, Wrangler
BRAKE SYSTEM BLEEDING
Hydraulic system bleeding is necessary any time air has been
introduced into system. Bleed brakes at all 4 wheels if master
cylinder lines have been disconnected or master cylinder has run dry.
Bleed brakes with vacuum bleeding equipment, pressure bleeding
equipment or by manually pumping brake pedal while using bleeder
tubes. Always bleed brake lines in sequence. See BLEEDING SEQUENCE
table.
MASTER CYLINDER BLEEDING
Bench Bleeding
1) Master cylinder must be bled before installation to
prevent excessive amounts of air from entering the brake system,
creating poor brake operation.
2) Place master cylinder in soft-jawed vise. DO NOT tighten
vise enough to damage master cylinder. Install bleeder tubes in both
outlets of master cylinder. See Fig. 1.
Fig. 1: Bleeding Master Cylinder
Courtesy of American Motors/Jeep Corp.
3) Fill master cylinder with clean brake fluid that meets DOT
3 specifications. Ensure that the end of bleeder tubes are submerged

in the brake fluid.
4) Using proper sized rod, apply and release master cylinder
until no air bubbles exist in brake fluid flow. Once all air bubbles
are gone from master cylinder secure cap and install.
5) Bleeder tubes should be left installed on master cylinder
until master cylinder in installed. Master cylinder must be bled at
brake lines and wheels after installation.
Bleeding On Vehicle
1) Install master cylinder on vehicle after bench bleeding.
Remove bleeder lines and install brake lines. DO NOT fully tighten
brake lines at this time.
2) Slowly force brake pedal to the floor and hold in this
position. Tighten brake lines and release brake pedal. Repeat
procedure until no air bubbles exist at brake lines. Remaining wheel
cylinder or calipers may be require bleeding.
HYDRAULIC CONTROL VALVES
Hold Off Valve
1) Prior to the pressure tank bleeding procedure, the hold
off valve incorporated in the combination valve must be correctly
positioned. This allows brake fluid to flow through the combination
valve to the entire brake system.
2) The valve stem of the hold off valve may be retained using
tools available from Chrysler Motors (C-4121) or General Motors
(J-23709) during bleeding procedure. See Figs. 2 and 3. Remove valve
retainer once brake bleeding procedure is complete.
CAUTION: DO NOT use rigid clamp to position valve stem. Damage to
the valve assembly may result causing brake failure.
Fig. 2: Positioning Hold Off Valve
Courtesy of American Motors/Jeep Corp.

Fig. 3: Positioning Hold Off Valve
Courtesy of American Motors/Jeep Corp.
VACUUM BLEEDING
Fill master cylinder. Install vacuum bleed equipment to first
bleeder valve to be serviced. Open bleeder valve 3/4-1 turn. Depress
vacuum pump and pull fluid into reservoir jar. Bleed each bleeder
valve in sequence. See BLEEDING SEQUENCE table.
PRESSURE BLEEDING
1) Clean master cylinder cap and surrounding area. Remove
cap. With pressure tank at least 1/2 full, connect to master cylinder
with adapters. Attach bleeder hose to first bleeder valve to be
serviced. See BLEEDING SEQUENCE table.
2) Place other end of hose in clean glass jar partially
filled with clean brake fluid so end of hose is submerged in fluid.
The hold off valve must be positioned properly before pressure
bleeding (if equipped). See HYDRAULIC CONTROL VALVES under BRAKE
SYSTEM BLEEDING in this article.
3) Open release valve on pressure bleeder. Follow equipment
manufacturer's pressure instructions or see PRESSURE BLEEDER SETTINGS
table. Open bleeder screw 3/4-1 turn and note fluid flow.
4) Close bleeder screw when fluid flowing is free of bubbles.
Repeat procedure on remaining wheels in proper sequence. Check brake
pedal operation after bleeding has been completed.
5) Remove pressure bleeding equipment and valve retainer from
hold off valve. Ensure that master cylinder is full of fluid.
PRESSURE BLEEDER SETTINGS TABLE









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Application psi (kg/cm)

All Models ............................... 15-20 (1.1-1.4)








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MANUAL BLEEDING
NOTE: When bleeding disc brakes, air may tend to cling to caliper
walls. Lightly tap caliper, while bleeding, to aid in
removal of air.
1) Fill master cylinder. Install bleeder hose to first
bleeder valve to be serviced. See BLEEDING SEQUENCE table. Submerge
other end of hose in clean glass jar partially filled with clean brake
fluid. See Fig. 4.
2) Open bleeder valve 3/4-1 turn. Depress brake pedal slowly
through full travel. Close bleeder valve and release pedal. Repeat
procedure until flow of fluid shows no signs of air bubbles.
NOTE: When bleeding brake system manually, ensure bleeder valve is
closed when brake pedal is released.
Fig. 4: Wheel Cylinder Bleeding Procedure
Courtesy of American Motors/Jeep Corp.
BLEEDING SEQUENCE