Tools / parts needed
- Digital multimeter (DC volts)
- OBD-II scanner capable of reading/clearing DTCs and performing throttle body / TPS relearn (preferred)
- Ratchet + metric socket set (8mm, 10mm commonly)
- Torx bit set (T20/T25/T30 commonly used on TPS/throttle body fasteners)
- Small flat screwdriver or pick (for connector release)
- Extension, swivel if needed
- Needle-nose pliers
- Replacement part: TPS sensor (or complete throttle-body assembly if TPS is integral on your engine). Also new throttle-body gasket or O-ring if removed.
- Dielectric grease, shop rags, gloves, safety glasses
- Wheel chocks, jack stands (if you must get under vehicle)

Safety precautions
- Park on level ground, parking brake set; chock wheels.
- Engine cold before working around intake/throttle body.
- Disconnect negative battery terminal and wait ~2 minutes before unplugging throttle electronics to avoid accidental short or uncontrolled throttle movement. Reconnect battery only when instructed.
- Wear eye protection and gloves.
- Avoid dropping hardware or debris into intake.
- If lifting vehicle, use jack stands; do not rely on the jack.

Step A — Locate TPS and initial access
1. Open hood. Locate air intake tube and airbox on the driver’s side leading to the throttle body on the intake manifold.
2. Remove air intake duct and airbox cover as needed (loosen hose clamps, remove a few screws/bolts) to expose throttle body and electrical connector. Keep fasteners organized.

Step B — Diagnostics / test before removal
1. Connect an OBD-II scanner. Check for related codes (P0120–P0124, P2135–P2138, P2100–P2102). Note codes and clear only after repairs.
2. Backprobe the TPS connector with the multimeter (DO NOT disconnect the connector to read reference voltage).
- Set multimeter to DC volts.
- With ignition ON (engine OFF), identify: 5 V reference wire, ground, and signal wire (service manual pinout or visually compare wires).
- With key ON, signal should be about 0.4–1.0 V at closed throttle and increase smoothly to ~4.0–4.8 V at wide-open throttle. No sudden jumps or drops. If reference is not ~5 V or signal is erratic, suspect wiring/ECU or TPS.
3. If you have no smooth voltage increase or out-of-spec values, proceed to replacement/testing physical sensor.

How the multimeter is used
- Set to DC volts. Backprobe the connector pins (use paperclip or probe through the connector seam) to measure 5 V reference and signal. Gradually move throttle manually (throttle plate open) while watching voltage; it must change smoothly without steps or dropouts.

Step C — Remove TPS or throttle body
Note: On WH/WK many models use a drive-by-wire throttle body where the TPS is integrated. Check whether the TPS is serviceable separate — if not, you must replace the entire throttle body.
1. Disconnect negative battery if you haven’t already.
2. Disconnect the electrical connector(s) to the TPS/throttle body (press release tab and pull straight out). Use a small screwdriver to release clip if stuck; avoid prying on wires.
3. Remove intake duct to clear working area.
4. If TPS is a separate sensor: remove the Torx screws holding it (usually 2–3 screws). Support sensor and pull out gently. Note orientation and any O-ring/gasket.
If TPS is integrated: remove mounting bolts to the throttle body (typically 4 bolts). Support throttle body, disconnect any coolant lines (plug to avoid fluid loss) and vacuum lines, then remove throttle body from manifold.
5. Inspect mating surfaces; clean with shop rag. Replace gasket or O-ring.

Step D — Install replacement
1. Install new TPS or throttle body in the exact orientation. Replace gasket/O-ring. Do not overtighten screws — snug to manufacturer spec. If no spec available, tighten evenly and gently; sensor screws are low-torque.
2. Reconnect wiring harness until it clicks.
3. Reinstall intake duct and airbox. Reconnect any vacuum or coolant lines removed.
4. Reconnect negative battery.

Step E — Reset / relearn procedure
1. Use OBD-II scanner: clear DTCs, then perform any throttle body alignment / TPS relearn procedure specified for Jeep (recommended). Many scanners have "Throttle Body Alignment" or "Throttle Learn".
2. If you don’t have a scanner, perform this basic procedure (some models require a proper tool — this is a generic fallback and may not replace a full OEM relearn):
- With parking brake on and transmission in Park, start engine and allow to idle until stable (may be rough for a short time).
- Cycle ignition (OFF -> ON) a few times, and drive gently for several miles to let ECM adapt.
- If check engine light returns or driveability issues persist, do not rely on this — use a scanner or dealer tool.
3. Verify no related DTCs return and that throttle response is smooth.

Common pitfalls and how to avoid them
- Mistaking APP (accelerator pedal position) correlation faults for TPS — check pedal sensor codes too (P2138 etc).
- Dropping screws or debris into intake — plug inlet if throttle body out.
- Cutting wires or breaking connector tabs when forcing connectors — depress release tabs before pulling.
- Overtightening sensor screws (plastic housing can strip or crack) — snug only.
- Not performing relearn with correct tool — can leave poor idle/hesitation; use OE-capable scan tool if possible.
- Replacing only the sensor when TPS is non-serviceable (integrated) — confirm whether TPS is available separately; on many WH/WK engines you must replace the full throttle body assembly.
- Ignoring harness/connector corrosion — inspect and clean contacts; dielectric grease on reconnect is helpful.
- Not checking for vacuum leaks after reassembly (intake tubing seals, clamps).

Torque/info notes
- Sensor screws are low-torque; throttle body bolts are medium torque. If exact torque values are required, reference factory service manual for your exact engine (3.7, 4.7, 5.7, diesel etc.) — when in doubt, hand-snug then 1/8 to 1/4 turn further, or consult manual.

Final checks
- Clear codes, perform relearn, test drive and monitor for returned codes or drivability issues.
- Re-check connector tightness and for vacuum leaks.
- If problem persists after correct installation and relearn, suspect wiring, ECU, or pedal sensor and perform further diagnostics.

End.
rteeqp73

Tools & consumables
- Metric socket set (8–15 mm) + ratchet and extensions
- Torque wrench (0–50 ft·lb)
- Flat and Phillips screwdrivers
- Pliers (clamp and slip-joint)
- Hose clamp pliers or screwdriver for screw clamps
- Drain pan (3–5 gal)
- Funnel and clean coolant container
- Gasket scraper / plastic razor blade
- Wire brush or clean rag
- Rubber gloves & safety glasses
- Floor jack and jack stands (only if splash shield removal required)
- Shop towels
- Vacuum coolant fill tool (highly recommended) or long-neck funnel
- Penetrating oil (for stuck hose/clamp bolts)
- Replacement parts: engine-specific thermostat (3.7L/4.7L = mechanical; 5.7 HEMI = electronic thermostat assembly), new thermostat gasket or O‑ring, new hose clamps (recommended), coolant (Mopar‑specified long‑life coolant or equivalent — do NOT mix different chemistries)

Safety first
- Work only when engine is cold. Hot coolant under pressure will cause severe burns.
- Wear safety glasses and gloves. Keep open cuts covered.
- Support vehicle with jack stands if you raise it; never rely on a jack alone.
- Catch coolant — do not dump down drains. Dispose/recycle per local laws.
- Battery disconnect recommended when working near electrical connectors (especially with 5.7 HEMI electronic thermostat).

Overview & notes
- Location: thermostat housing is at the end of the upper radiator hose where it connects to the engine (passenger side). On 3.7L/4.7L it’s a conventional thermostat in a small housing; 5.7 HEMI uses an electronic thermostat assembly — part and procedure differ slightly.
- Always buy the thermostat specific to your engine. Replace the O‑ring / gasket with the new thermostat — do not reuse.

Step‑by‑step procedure
1) Preparation
- Park on level ground, set parking brake, chock wheels, engine cold.
- Open hood, remove engine cover and air intake components blocking access to the thermostat housing (often the airbox and upper intake snorkel; on some models you’ll need to remove the battery to gain clearance).
- Place drain pan under radiator drain or lower hose.

2) Drain coolant to below thermostat level
- Open radiator petcock (or loosen lower radiator hose) and drain enough coolant to drop level below the thermostat housing so you don’t spill when you open it. Catch used coolant.
- If unsure, remove only enough to avoid full drain; you can recover/replace remaining coolant.

3) Remove components for access (if required)
- Remove upper radiator hose from thermostat housing: loosen clamp, twist hose free. Use penetrating oil if stuck and pliers to compress spring clamps. Have shop towel ready for residual coolant.
- If access requires it, remove splash shield or brackets. Use jack/stands if needed.

4) Remove thermostat housing
- Locate and remove the housing bolts (usually 2–3 bolts). Use the appropriate socket and extension.
- Support the housing as you remove bolts — many housings are plastic and fragile.
- Carefully break the seal and lift the housing away. Expect residual coolant to pour; move drain pan.

5) Remove old thermostat and clean mating surfaces
- Note thermostat orientation before removal. For conventional thermostats: spring side faces the engine block (the thermostat valve faces the radiator outlet). For an electronic assembly, follow the part orientation instructions.
- Remove old thermostat and O‑ring/gasket.
- Clean mating surfaces on both housing and engine with a plastic scraper and rag until bare and flat. Do not gouge sealing surfaces. Remove old gasket material and corrosion.

6) Install new thermostat
- Verify new thermostat is the correct part for your engine.
- Install new thermostat in same orientation as removed (spring toward the engine for mechanical thermostats).
- Install new O‑ring/gasket — lightly lubricate O‑ring with coolant or clean engine oil so it seats without twisting.
- If replacing electronic thermostat assembly on a HEMI, make sure electrical connector harness is accessible and not pinched.

7) Reinstall housing and torque bolts
- Position housing carefully and start bolts by hand to avoid cross‑threading.
- Tighten bolts evenly in a crisscross pattern. Torque to manufacturer spec — if you don’t have the manual, torque small housing bolts to approximately 8–12 ft·lb (tighten snugly but DO NOT overtighten; plastic housings crack easily).
- Reconnect upper radiator hose and install new hose clamps if supplied.

8) Reassemble removed components
- Reinstall airbox, intake hose, battery, engine cover, splash shield, etc.
- Reconnect any electrical connectors you removed.

9) Refill and bleed cooling system
- Refill with correct coolant type to specified concentration.
- If you have a vacuum fill tool, use it — it makes bleeding straightforward and prevents air pockets.
- Without a vacuum filler: fill radiator/reservoir, start engine with heater on high, loosen any cooling system bleeder screw (if equipped on your thermostat housing or heater hose) until coolant flows steady, then tighten.
- Squeeze the upper radiator hose periodically to help dislodge trapped air.
- Monitor coolant level as thermostat opens (engine reaches operating temp) and add coolant as needed.
- Continue until no more air bubbles and level stable; top off reservoir.

10) Final checks
- With engine at operating temperature, inspect for leaks around housing and hose.
- Re‑torque bolts after cool down if necessary.
- After a short test drive, recheck coolant level and inspect for leaks again. Replace coolant cap and secure everything.

Common pitfalls & avoidance
- Opening hot system: always wait for cold engine. Hot coolant causes severe injury.
- Wrong thermostat orientation: always install spring side toward engine (mechanical). Double‑check part instructions for electronic assemblies.
- Reusing old gasket/O‑ring: leads to leak — always replace seal.
- Overtightening housing bolts: Jeep thermostat housings are often plastic — bolts strip or crack housing. Use correct torque and even tightening sequence.
- Not bleeding air: trapped air causes hot spots/overheating. Use vacuum filler or bleed procedure until no air.
- Mixing coolant types: mixing OAT/Dex‑Cool and other chemistries can cause sludge. Use manufacturer‑specified coolant.
- Damaging connectors/sensors: on 5.7 HEMI electronic thermostat, disconnect gently and avoid pulling wires.
- Ignoring corroded hoses/clamps: if hose or clamp is old/soft, replace to avoid future leaks.

Specific notes for HEMI 5.7L
- This engine uses an electronic thermostat assembly (often sold as a housing/thermostat/electronic valve). Replacement usually requires the whole assembly and may have different electrical connections and bleeding steps. Disconnect battery before replacing if working near electrical connectors. Use a scan tool if you get thermostat fault codes after replacement — some systems need the PCM to adapt.

Disposal & final
- Properly dispose of used coolant.
- Keep the vehicle monitored for several days for leaks and coolant level changes.

That’s the full, practical procedure. Follow torque specs from a factory or reputable repair manual for exact values for your engine.
rteeqp73