🏷️ Basic Information Identification Make: Mercedes-Benz Model: W126 SEC Year: 1988 Codes Chassis Code: W126 Body Style Code: C126 👋 Introduction Market Position Target Audience: Mercedes-Benz W126 SEC owners, independent repair shops, enthusiasts. Competitive Analysis Advantage: Vehicle-specific, factory-level data, a significant advantage over generic repair guides. Key Features Feature 1: Vehicle-specific information, not generic. Feature 2: Complete step-by-step instructions, diagrams, illustrations, and wiring schematics. Feature 3: All-in-one PDF format for easy access and printing. Feature 4: Designed for ease of use and accurate repair. 📋 Manual Details Coverage Areas Primary Focus: Service and Repair Scope: All Models & All Repairs A-Z Page Count Estimated Pages: Varies by specific factory publication, but comprehensive electronic manuals typically exceed 1000 pages. Manual Type Type: Factory Authorized Service and Repair Manual Language Language: English Format Format: PDF Distribution: Digital Download 📖 Manual Coverage Systems Covered Engine Mechanical: Complete overhaul, component testing, torque specifications, timing, seals, gaskets. Engine Control System: Fuel injection (CIS-E), ignition system, electronic control unit (ECU) diagnostics and repair. Fuel System: Fuel pump, injectors, fuel pressure regulator, fuel lines, filter replacement. Emission Control: Catalytic converter, EGR system, O2 sensors, evaporative emission control (EVAP). Intake Exhaust Cooling: Air intake system, exhaust manifold, muffler, radiator, cooling fan, thermostat. Lubrication: Oil pump, oil filter, oil pressure, oil capacities, oil types. Ignition Starting Charging: Spark plugs, ignition coils, distributor, starter motor, alternator, battery. Automatic Transmission: 4-speed automatic (722.3), internal components, hydraulic control, torque converter, fluid service, adjustments. Manual Transmission: Not applicable to W126 SEC models. Drive Shaft Differential: Driveshaft, universal joints, rear axle, differential service and repair. Suspension: Front and rear suspension components, shock absorbers, springs, bushings, alignment specifications. Wheels Tires: Wheel types, tire sizes, inflation pressures, bolt patterns, torque specifications. Brake System: Hydraulic system, calipers, rotors, brake pads, ABS (Anti-lock Braking System) diagnostics and repair. Parking Brake: Mechanism, adjustments, service. Steering: Steering column, power steering system, pump, rack and pinion, adjustments. Air Conditioning: Refrigerant system, compressor, controls, diagnostics, recharge procedures. Supplemental Restraint System: Airbag system (if equipped), seat belts, pretensioners. Engine Immobilizer: Security systems and immobilizer functionality. Cruise Control: System components, diagnostics, repair. Wiper Washer: Wiper motor, linkage, washer pump, fluid reservoir. Door Locks: Central locking system, actuators, vacuum system (if applicable). Meter Audio Visual: Instrument cluster, gauges, audio system, speaker wiring. Horn: Horn system, relay, button. Glass Mirrors: Windshield, side glass, rear glass, mirror replacement, adjustment. Instrument Panel: Dash panel removal, illumination, warning lights. Seats: Seat adjustment mechanisms, heating (if equipped), upholstery. Body Panels: Hood, doors, fenders, trunk lid removal and installation, adjustments. Exterior Interior Trim: Bumper removal, trim pieces, interior panels, headliner. Electrical System: Comprehensive wiring diagrams, component testing, fuse box layout, lighting systems. Multiplex Can Communication: While CAN was nascent in 1988, early multiplexing systems might be covered. Procedures Included Maintenance: Scheduled maintenance, fluid changes, filter replacements, tune-ups. Diagnostics: Troubleshooting guides, fault code interpretation, component testing procedures. Repair: Detailed step-by-step instructions for component removal, repair, and reinstallation. Installation: Procedures for installing new or replacement parts. Adjustments: Specific adjustments for engine timing, brakes, suspension, etc. Technical Depth Depth: Comprehensive, covering everything from basic fluid checks to complete engine and transmission overhauls. Detail Level: Factory-level detail with step-by-step instructions, diagrams, illustrations, and wiring schematics. 📊 Manual Specifications File Format Compatibility: Windows Vista (32/64), XP, ME, 98, NT, 2000, and Mac OS. Required Software: Adobe PDF Reader and Winzip (free online). Print Quality Printability: All pages are printable, allowing for enlarged diagrams and specific page printing. Binding Type Binding: Not Applicable (Digital PDF format). Paper Type Paper: Not Applicable (Digital PDF format). ⚙️ Engine Specifications Primary Engine Engine Type: V8 SOHC (M116/M117 Family) Engine Displacement Liter: 5.0L (for 500SEC) Engine Displacement Cubic Inch: 303 cu in (for 500SEC) Performance Horsepower: Approx. 240-270 hp (depending on market and specific engine variant) Torque: Approx. 300-325 lb-ft (depending on market and specific engine variant) Fuel System Fuel Injection Type: Bosch CIS-E (Continuous Injection System - Electronic) Fuel Type: Unleaded Gasoline 🔧 Transmission Standard Transmission Type: 4-Speed Automatic (722.3) Optional Transmission Type: Manual transmission was not offered on the W126 SEC. Features Hydraulic Control: Hydraulic valve body with electronic control for shift points. 📐 Dimensions Exterior Wheelbase Inches: 112.2 inches Length Inches: 196.9 inches Width Inches: 70.5 inches Height Inches: 54.3 inches Weights Curb Weight Lbs: Approx. 3900-4100 lbs 🛡️ Safety Features Ratings Crash Test Info: While official US NHTSA ratings for this era are less detailed, Mercedes-Benz vehicles of this period were known for robust safety engineering. Active Features ABS: Standard Anti-lock Braking System (ABS) Traction Control: ASR (Acceleration Slip Regulation) became available later in the W126 generation, but was not standard on all 1988 SEC models. Passive Features Airbags: Driver airbag became standard in 1988 for the W126 SEC. Seat Belts: Three-point inertia-reel seat belts front and rear, seat belt pretensioners. Body Construction: Reinforced safety cell, crumple...