The 2003 Highlander is a versatile mid-size SUV built on the reliable MC platform, offering seating for up to seven passengers and available in front-wheel drive or full-time all-wheel drive configurations. Powered by a robust 3.0L V6 engine producing 220 horsepower, this vehicle combines a comfortable ride with practical utility, making it a strong contender in its segment. Known for its exceptional reliability, quality engineering, and strong safety ratings, the Highlander was designed to meet the needs of families and individuals seeking a capable and dependable vehicle for everyday use and varied driving conditions. This comprehensive service manual provides detailed information for the maintenance, diagnosis, and repair of the 2003 Highlander. It covers all essential vehicle systems, including the powertrain, chassis, and electrical components, offering in-depth guidance on procedures such as scheduled maintenance, troubleshooting common issues, and performing complex repairs. With extensive technical specifications, diagnostic flowcharts, and clear instructions, this manual serves as an indispensable resource for owners, technicians, and mechanics aiming to ensure the optimal performance, longevity, and safety of their Highlander. 🏷️ Basic Information Identification Make: Toyota Model: Highlander Year: 2003 Generation First Generation Designation: XU20 Codes Chassis Code: MCU20/MCU25 (V6), MHU20/MHU25 (Hybrid) 👋 Introduction Market Position Segment: Mid-size SUV / Crossover Utility Vehicle Target Audience: Families, individuals seeking versatile transportation, all-weather capability Competitive Analysis Key Competitors: Honda CR-V, Ford Escape, Chevrolet Equinox, Nissan Murano, Subaru Forester Key Features Vehicle Platform: Camry/Solara platform (MC platform) Drivetrain Options: Front-Wheel Drive (FWD), Full-Time All-Wheel Drive (AWD) Body Styles: 5-door SUV Notable Distinction: Offered with a hybrid powertrain (Highlander Hybrid) in some markets, though the 2003 model primarily focused on the gasoline V6. 📋 Manual Details Coverage Areas Primary Focus: Mechanical, Electrical, Body, Chassis, Maintenance, Diagnostics Page Count Estimated Pages: Approx. 2000+ pages (typical for comprehensive service manuals) Manual Type Type: Official Factory Service Manual (FSM) / Repair Manual Software Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Powertrain: Engine (3.0L V6 1MZ-FE), Transmission (5-speed Automatic, Hybrid Synergy Drive), Fuel System, Exhaust System Chassis: Suspension (Front MacPherson Strut, Rear Independent Multi-link), Steering (Power Rack and Pinion), Brakes (Front Ventilated Disc, Rear Disc, ABS, EBD) Electrical: 12V Battery System, Charging System, Starting System, Lighting, Instrumentation, Audio System, HVAC Controls, Power Accessories (Windows, Locks, Seats), SRS Airbag System, Immobilizer System Body: Body Panel Repair, Door Assemblies, Interior Trim, Exterior Trim, Bumpers, Glass, Sealing Procedures Included Maintenance: Scheduled Maintenance (Oil Changes, Filter Replacements, Fluid Checks), Tune-Up Procedures, Belt Inspections, Spark Plug Replacement Diagnostics: Troubleshooting Flowcharts, Diagnostic Trouble Codes (DTCs), Scan Tool Usage, Component Testing Procedures Repair: Engine Mechanical (Timing Belt, Head Gasket, Piston/Ring Replacement), Transmission Overhaul, Brake Caliper/Rotor Replacement, Suspension Component Replacement, Electrical Component Diagnosis and Replacement Specifications: Torque Specifications, Electrical Schematics, Component Locations, Fluid Capacities, Diagnostic Data Technical Depth Depth: Comprehensive: Covers basic maintenance to full engine and transmission rebuilds, including electrical diagnostics and bodywork. Suitable for professional technicians and advanced DIYers. 📊 Manual Specifications File Format File Type: PDF Searchability: Text-searchable (optimally for quick information retrieval) Print Quality Printability: Printable pages for easy workshop reference Binding Type Binding: N/A (Digital Download) Paper Type Paper: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Code: 1MZ-FE Configuration: 3.0L V6, 24-valve, DOHC with VVT-i Performance Horsepower: 220 hp @ 5800 rpm Torque: 222 lb-ft @ 4400 rpm Fuel System Induction: Electronic Fuel Injection (EFI) Fuel Type: Unleaded Gasoline Engine Management ECU: Denso Maintenance Timing Belt Replacement Interval: 90,000 miles or 9 years (whichever comes first) Spark Plug Type: Iridium (e.g., Denso PK20TR11) 🔧 Transmission Standard Type: U151E (5-speed Automatic) Optional Type: N/A (Hybrid variant had a unique system) Features Mode: Electronically Controlled Transmission (ECT), AI Shift Control Fluid Specifications Transmission Fluid Type: Toyota Genuine ATF WS (World Standard) or equivalent Fluid Capacities Automatic Transmission Fluid Capacity: Approx. 3.7 quarts (drain and fill) 📐 Dimensions Exterior Length: 188.4 inches Width: 72.0 inches Height: 67.5 inches Wheelbase: 106.1 inches Interior Seating Capacity: 7-passenger (optional third row) Cargo Cargo Volume Behind Second Row: Approx. 39.7 cubic feet Weights Curb Weight FWD: Approx. 3,805 lbs Curb Weight AWD: Approx. 3,950 lbs Towing Capacity: 3,500 lbs (with proper towing package) 🛡️ Safety Features Ratings NHTSA Front Impact: 5-star NHTSA Side Impact: 5-star IIHS Moderate Overlap Front: Good Active Features ABS: Standard Anti-lock Braking System (ABS) Ebd: Standard Electronic Brake-force Distribution (EBD) Traction Control: Optional Traction Control System (TRAC) Stability Control: Optional Vehicle Stability Control (VSC) Passive Features Airbags: Standard front airbags, available front side-impact airbags and side-curtain airbags Seatbelts: 3-point seatbelts with pretensioners and force limiters 💡 Technology Features Infotainment Audio System: Standard AM/FM/CD player, optional premium JBL audio system with amplifier and subwoofer. Navigation: Optional factory-installed GPS navigation system. Driver Assistance Cruise Control: Standard cruise control. Connectivity Power Accessories: Power windows, power door locks, remote keyless entry. 🔧 Maintenance Service Intervals Oil Change Interval:...