🏷️ Basic Information

Make:

Jeep

Model:

Wrangler TJ

Year:

2003

Chassis Code:

TJ

Engine Code Primary:

4.0L (ID: ERH)

👋 Introduction

Vehicle Segment:

Compact SUV / Off-Road Vehicle

Jeep Philosophy:

The TJ Wrangler embodies Jeep's legacy of ruggedness, off-road capability, and open-air freedom, distinguishing it from mainstream SUVs.

Direct Competitors 2003:

Toyota 4Runner, Ford Explorer Sport Trac, Chevrolet Tracker (though less direct).

Key Differentiators:

Solid front axle (a significant off-road advantage), coil spring suspension, iconic design, superior off-road articulation and capability.

Design Philosophy:

Evolution of the classic CJ, retaining classic Jeep styling cues with modern mechanicals and safety features. Distinctive round headlights and seven-slot grille.

Frame Chassis:

Body-on-frame construction providing robust durability and off-road resilience.

Powertrain Options:

Renowned 4.0L inline-six engine and available 2.4L four-cylinder engine.

Convertibility:

Standard soft top with removable doors and windshield, optional hardtop for all-weather use, offering unparalleled open-air driving experience.

📋 Manual Details

Systems Covered Overview:

Comprehensive coverage of all major mechanical, electrical, and body systems.

Specific Systems Covered:

Engine Mechanical, Engine Lubrication, Engine Cooling, Fuel System, Ignition System, Exhaust System, Clutch, Manual Transmission, Automatic Transmission, Transfer Case, Drive Axles, Suspension (Front and Rear), Steering, Brakes, Wheels and Tires, Body and Frame, Heating and Air Conditioning (HVAC), Electrical System (Power Distribution, Lighting, Instrumentation, Body Control Modules, Engine Control Modules), Powertrain Control Module (PCM), Audio Systems, Security Systems.

Estimated Pages:

1000+

Type:

Service and Repair Manual

Manual Scope:

Factory-level service and repair information.

Language:

English

Format:

Digital Download (PDF)

📖 Manual Coverage

Engine Mechanical:

Detailed procedures for engine assembly, disassembly, inspection, and repair of all internal components (pistons, rings, connecting rods, crankshaft, camshaft, valves, cylinder heads, etc.).

Engine Lubrication:

Oil pump operation, oil filter replacement, oil pan removal/installation, lubrication system diagnostics.

Engine Cooling:

Radiator, coolant pump, thermostat, hoses, fan operation, coolant type and capacity specifications, flushing and refilling procedures.

Fuel System:

Fuel pump, fuel injectors, fuel filter, fuel pressure testing, evaporative emission control (EVAP) system.

Ignition System:

Spark plugs, ignition coils, crankshaft position sensor, camshaft position sensor, ignition timing.

Exhaust System:

Exhaust manifold, catalytic converter, muffler, oxygen sensors, exhaust system inspection and repair.

Transmission Manual:

NV3550 5-speed manual transmission: disassembly, assembly, clutch replacement, shift linkage adjustment.

Transmission Automatic:

42RLE 4-speed automatic transmission: component identification, fluid capacity and type, transmission service, torque converter replacement.

Transfer Case:

NV241OR 'Atlas' (or similar) 4WD transfer case: operation, maintenance, fluid type and capacity, removal and installation.

Suspension:

Front coil spring suspension (Solid Dana 30 axle), rear coil spring suspension (Solid Dana 35 axle), control arms, track bar, sway bar links, shock absorbers, bushings.

Steering:

Power steering pump, steering gear, tie rods, steering column, alignment specifications.

Brakes:

Front disc brakes, rear drum brakes (or optional rear discs depending on trim/options), ABS system, brake fluid type and bleeding procedures, parking brake.

Electrical System:

Wiring diagrams, fuse box layouts, battery, alternator, starter motor, lighting circuits, power windows, power locks, horn, wipers.

Body And Frame:

Body panel removal/installation, door hinges, tailgate, soft top/hardtop removal/installation, frame inspection and repair.

HVAC:

A/C system components, refrigerant type and capacity, heater core, blower motor, control panel operation, diagnostic procedures.

Maintenance Procedures:

Oil and filter changes, air filter replacement, fuel filter replacement, spark plug replacement, coolant flushes, brake fluid service, tire rotation and balancing, battery inspection, belt inspection/replacement.

Repair Procedures:

Engine component repair (e.g., head gasket replacement, piston ring replacement), transmission overhaul and repair, clutch replacement, suspension component replacement (shocks, springs, ball joints, tie rods), brake caliper/rotor/drum replacement, power steering system repair, HVAC component replacement.

Troubleshooting:

Diagnostic procedures for engine performance issues, starting problems, electrical faults, braking issues, HVAC malfunctions, based on symptom analysis and diagnostic codes.

Diagnostics:

OBD-II diagnostic trouble code (DTC) interpretation, sensor testing, actuator testing, wiring harness continuity checks, use of diagnostic scan tools.

Installation Procedures:

Component replacement and installation, accessory installation, some aftermarket modification guidance.

Depth Level:

Comprehensive and in-depth, suitable for both DIY mechanics and professional technicians.

Diagnostic Tools Required:

Includes information on required specialized tools, torque wrenches, diagnostic scanners, multimeters, and fluid evacuation equipment.

📊 Manual Specifications

File Type:

PDF

Searchability:

Searchable text content for quick information retrieval.

Resolution:

High-resolution, clear and legible text and diagrams.

Illustrations:

Profusely illustrated with clear, step-by-step diagrams, schematics, and photographs.

Digital Format:

Downloadable PDF, no physical binding.

Digital Equivalent:

Simulates high-quality service manual pages.

⚙️ Engine Specifications

Engine Type:

Inline 6-Cylinder (I6), Overhead Valve (OHV)

Engine Name:

PowerTech

Displacement:

3952 cc (241 cu in)

Bore X Stroke:

3.88 x 3.58 in (98.5 x 91.0 mm)

Compression Ratio:

8.8:1

Horsepower 4.0L:

190 hp @ 4600 rpm

Torque 4.0L:

235 lb-ft @ 3200 rpm

Fuel Delivery:

Multi-port Fuel Injection (MPI)

Fuel Type:

Unleaded Gasoline

Engine Type:

Inline 4-Cylinder (I4)

Engine Displacement:

2429 cc (148 cu in)

Engine Performance:

122 hp @ 4800 rpm / 147 lb-ft @ 3200 rpm (approximate, depending on spec)

🔧 Transmission

Transmission Type:

NV3550 5-Speed Manual

Transmission Type:

42RLE 4-Speed Automatic

Transfer Case Standard:

NV241OR (Command-Trac) 2-Speed, Part-Time 4WD

Transfer Case Optional:

NV241OR-HD (Rock-Trac) 4WD with 4:1 low range (typically on Rubicon models, though rare for '03 TJ)

Fluid Type:

NV3550: Mopar Manual Transmission Lubricant or equivalent (e.g., Castrol Syntrans FE 75W-80 GL-4)

Fluid Type:

42RLE: ATF+4 (MS-9602)

Fluid Type:

NV241OR: Mopar NV241 Transfer Case Lubricant or equivalent (e.g., Castrol Syntrans XYZ 75W-90 GL-5)

📐 Dimensions

Length:

158.5 in (4026 mm)

Width:

73.4 in (1864 mm)

Height:

70.3 in (1786 mm) (with soft top)

Wheelbase:

93.4 in (2372 mm)

Passenger Volume:

80.1 cu ft (2.27 m³)

Cargo Volume Behind Rear Seat:

13.2 cu ft (0.37 m³)

Cargo Volume With Rear Seat Folded:

46.0 cu ft (1.30 m³)

Curb Weight:

3380 - 3650 lbs (1533 - 1656 kg) (approximate, varies by configuration)

Towing Capacity:

2000 lbs (907 kg)

Payload Capacity:

800 lbs (363 kg)

Minimum Ground Clearance:

10.1 in (257 mm)

Approach Angle:

38.4°

Breakover Angle:

23.5°

Departure Angle:

30.2°

🛡️ Safety Features

NHTSA Front Crash Test:

4/5 Stars (Driver/Passenger)

NHTSA Side Impact Test:

Not rated or N/A due to vehicle design characteristics (often open body/lack of B-pillar)

ABS:

Standard Anti-lock Braking System (ABS) on rear wheels (4-wheel ABS optional or standard on some trims)

Traction Control:

Optional Traction Control System (TCS)

Airbags:

Driver and Passenger front airbags

Seatbelts:

3-point seat belts with pretensioners

Rollover Protection:

Sport roll bar integrated into the interior structure.

💡 Technology Features

Audio System:

Standard AM/FM stereo with CD player. Optional premium audio systems available.

Speakers:

Typically 4 or 6 speaker configurations.

ABS:

Standard rear ABS, optional 4-wheel ABS.

Traction Control:

Optional TCS.

Navigation:

No factory-integrated navigation system; aftermarket solutions required.

Bluetooth:

No factory Bluetooth connectivity.

Aux Input:

Optional auxiliary input jack available on some audio systems.

🔧 Maintenance

Oil Change Interval:

Every 3,000-5,000 miles (4,800-8,000 km) or 6 months, depending on driving conditions. Consult manual for specific guidance.

Air Filter Replacement:

Every 15,000 miles (24,000 km) or annually, or more frequently in dusty conditions.

Fuel Filter Replacement:

Every 30,000 miles (48,000 km)

Spark Plug Replacement 4.0L:

Every 60,000 miles (96,000 km) (use Champion copper core spark plugs, e.g., RC12LYC)

Coolant Flush And Replace:

Every 30,000 miles (48,000 km) or 2 years.

Engine Oil Type 4.0L:

API SP/SN or ILSAC GF-6A SAE 10W-30 or 10W-40 (check owner's manual for exact recommendation based on temperature)

Engine Oil Capacity 4.0L:

6 US quarts (5.7 L) with filter

Brake Fluid Type:

DOT 3

Power Steering Fluid Type:

Mopar Power Steering Fluid or equivalent (e.g., ATF+4 for some models/years, confirm with manual)

Common Issues 4.0L Engine:

Cracking exhaust manifolds, heater core leaks, oil filter adapter housing leaks, occasional valve seat recession issues in higher mileage examples.

Common Issues Suspension Steering:

Worn control arm bushings, track bar wear, ball joint wear, steering stabilizer failure, frame rust (particularly in areas exposed to road salt).

Common Issues Transmission:

Manual transmission wear (especially clutch), automatic transmission solenoid issues, transfer case seal leaks.

Common Issues Electrical:

Corrosion on electrical connectors, particularly under the dashboard and in the engine bay, ABS sensor failures, instrument cluster failures.

Common Issues Body:

Soft top leaks, door seal degradation, windshield seal leaks, rust on body tub and fenders.

📚 Vehicle History

Jeep Legacy:

Jeep's heritage dates back to World War II with the Willys MB, establishing a long-standing reputation for ruggedness and off-road capability.

Tj Introduction:

The TJ Wrangler was introduced for the 1997 model year as a successor to the YJ Wrangler, marking a significant return to the classic CJ design cues, including round headlights.

Tj Distinctive Features:

Key to the TJ's advancement was the adoption of coil spring suspension, replacing the YJ's leaf springs, significantly improving ride quality and off-road articulation.

Tj Design Changes 2003:

While major redesigns occurred in earlier TJ years, 2003 saw minor updates and continued refinement of existing systems. The 42RLE automatic transmission became more prevalent, replacing the older 32RH.

Production Years:

1997-2006

Manufacturing Location:

Toledo, Ohio, USA

🏆 Awards & Recognition

Off Road Capability:

Consistently recognized by off-road enthusiasts and publications for its superior off-road prowess and ruggedness.

Design Icon:

The TJ Wrangler's design has become iconic, celebrated for its blend of classic Jeep aesthetics and modern functionality.

Resale Value:

Jeep Wranglers generally hold strong resale value due to their enduring popularity and off-road capability.

Manual Quality:

This manual is a high-quality reproduction of factory service information, ensuring accuracy and completeness for repair and maintenance tasks.