🏷️ Basic Information

Make:

Mercedes-Benz

Model:

S-Class

Chassis Code:

W221

Model Year:

2009

Product Name:

Mercedes Benz S-Class W221 Complete Workshop Service Repair Manual 2009

👋 Introduction

Market Position:

The W221 S-Class represents the pinnacle of Mercedes-Benz luxury sedans, a flagship model known for its advanced technology, supreme comfort, and executive presence. This manual caters to owners and technicians servicing these sophisticated vehicles.

Target Audience:

Professional automotive technicians, Mercedes-Benz dealerships, DIY enthusiasts with advanced mechanical skills, and fleet maintenance facilities.

Competitive Analysis:

Competed directly with other top-tier luxury sedans such as the BMW 7 Series, Audi A8, Lexus LS, and Porsche Panamera. The W221 distinguished itself with its blend of opulent interior, cutting-edge safety and comfort features, and robust engineering.

Key Features:

Advanced driver-assistance systems (DISTRONIC PLUS, LANE KEEPING ASSIST), COMAND infotainment system, multi-contour seats with massage functions, ambient lighting, optional rear-seat entertainment, premium sound systems (e.g., Harman Kardon, Bang & Olufsen), extensive use of luxury materials, and powerful yet refined engine options.

4Matic All Wheel Drive:

Optional permanent all-wheel drive system, enhancing traction and stability in various road conditions. The manual covers its maintenance and troubleshooting.

📋 Manual Details

Coverage Areas:

Engine, Transmission, Drivetrain, Suspension, Steering, Brakes, Electrical Systems, HVAC, Bodywork, Interior, Diagnostics, Maintenance, Repair Procedures, Troubleshooting, Specifications, Wiring Diagrams.

Page Count:

Extensive (Exact count not specified in product info, but implies comprehensive)

Manual Type:

Workshop Service Repair Manual

Language:

English

Format:

Downloadable

📖 Manual Coverage

Systems Covered:

Engine mechanical (M272, M273, M156, M275, M276), engine management (ME-SFI), fuel injection, ignition, exhaust, cooling, lubrication, transmission (7G-TRONIC 722.9, NAG2), drivetrain (RWD, 4MATIC AWD), suspension (AIRMATIC, ACTIVE BODY CONTROL), steering (SRS, EPS), braking (ABS, ESP, SBC), hydraulic systems, pneumatic systems, electrical systems (CAN-Bus, LIN-Bus, MOST), body control modules, climate control (THERMATIC, THERMOTRONIC), infotainment, lighting, safety systems (Airbags, Seatbelts), diagnostics (OBD-II, XENTRY/DAS).

Procedures Included:

Routine maintenance (oil changes, filter replacements, fluid checks), tune-ups, engine overhaul, transmission service and repair, brake system maintenance and repair, suspension component replacement, steering system diagnostics and repair, electrical component testing and replacement, HVAC system servicing, body panel repair and alignment, interior trim removal and installation, diagnostic trouble code interpretation, wiring diagram troubleshooting, component testing, calibration procedures.

Climate Control System Repair:

Comprehensive coverage of the THERMATIC and THERMOTRONIC automatic climate control systems, including refrigerant handling, component replacement (compressor, evaporator, heater core), and diagnostic checks.

Technical Depth:

Comprehensive: Covers everything from basic preventative maintenance and scheduled services to advanced diagnostics, component-level repairs, and complete overhauls. Includes detailed technical specifications, torque values, diagnostic procedures, and wiring diagrams essential for professional-level repairs.

Diagnostic Tools And Procedures:

Detailed procedures for using Mercedes-Benz diagnostic tools like XENTRY/DAS (equivalent). Covers reading and clearing fault codes, live data monitoring, component activation, and system resets/adaptations.

Body And Chassis Repair:

Includes procedures for body panel alignment, rust repair, frame straightening principles (where applicable), and maintenance of underbody coatings.

Wiring Diagrams:

Extensive, color-coded wiring diagrams for all major systems (engine, transmission, ABS, airbags, lighting, infotainment, etc.), crucial for diagnosing electrical faults.

Interior Trim And Upholstery:

Procedures for removing and installing interior trim panels, headliner, seats, and dashboard components, including care instructions for leather and wood accents.

Tire And Wheel Service:

Specifications for tire sizes, pressures, wheel torque values, and procedures for tire rotation and balancing.

📊 Manual Specifications

File Format:

Likely PDF (digital download), optimized for searchability and printing.

Searchability:

Likely includes a searchable PDF index or text layer for quick access to specific topics and components.

Print Quality:

High-resolution, clear diagrams and text, suitable for professional printing.

Binding Type:

N/A (Downloadable format)

Paper Type:

N/A (Downloadable format)

⚙️ Engine Specifications

Engine Variants Covered:

S350 (M272 V6, 3.5L), S550 (M273 V8, 5.5L), S600 (M275 V12 Bi-Turbo, 5.5L), S63 AMG (M156 V8, 6.2L), S65 AMG (M275 V12 Bi-Turbo, 6.0L).

Typical Performance Figures:

Varies by engine: Horsepower ranges from ~270 hp (S350) to ~600 hp (S65 AMG). Torque figures are similarly impressive, reflecting the luxury and performance mandate.

Fuel System Type:

Electronic fuel injection (EFI) with sophisticated engine management systems (ME-SFI, CGI for newer variants). Specifics on fuel pressure, injector types, and pump specifications are detailed within the manual.

Catalytic Converter And Emission Controls:

Details on emission control systems, including catalytic converters, oxygen sensors, and evaporative emission control (EVAP) systems, along with diagnostic procedures.

Engine Control Unit ECU:

ME-SFI (Motorelektronik - Sequentielle Kraftstoffeinspritzung) for gasoline engines, CD I (Common Rail Diesel Injection) for diesel variants if applicable, and specialized ECUs for AMG models. Manual provides detailed system descriptions.

Amg Engine Details:

Detailed specifications for naturally aspirated 6.2L V8 (M156) in the S63 AMG and twin-turbocharged 5.5L V12 (M275) in the S600/S65 AMG, including performance outputs and unique components.

🔧 Transmission

Standard Transmission Type:

7-speed automatic transmission (7G-TRONIC, 722.9) for most models.

7G Tronic Features:

Features like DIRECT SELECT gear selector, electronically controlled shift points, and efficiency-oriented programming are covered.

Optional Transmission Type:

Some AMG models may feature different AMG SPEEDSHIFT transmissions (e.g., MCT). The V12 models may also have specific transmission variants.

Transmission Features:

Adaptive shift logic, manual mode (Tiptronic), Sport and Comfort modes. Fluid type and change intervals are critical for longevity.

Transmission Control Module:

Details on the operation and diagnostics of the Transmission Control Module (TCM) and its interaction with the engine and chassis control units.

📐 Dimensions

Wheelbase:

Standard: 3035 mm (119.5 in); Long Wheelbase (V221): 3165 mm (124.6 in).

Length:

Standard: 5079 mm (200.0 in); Long Wheelbase: 5209 mm (205.1 in).

Width:

1872 mm (73.7 in)

Height:

1477 mm (58.1 in)

Front Headroom:

Approx. 1010 mm (39.8 in)

Rear Legroom:

Standard Wheelbase: Approx. 965 mm (38.0 in); Long Wheelbase: Approx. 1035 mm (40.7 in).

Curb Weight:

Varies significantly by engine and options, typically starting from around 1900 kg (4189 lbs) for V6 models up to over 2100 kg (4630 lbs) for V12 models.

Gross Vehicle Weight Rating Gvwr:

Specifies the maximum allowable weight of the vehicle, including passengers and cargo. Detailed in the manual for specific configurations.

🛡️ Safety Features

NHTSA Ratings:

Generally received high safety ratings from NHTSA and IIHS, benefiting from advanced safety structures and occupant protection.

IIHS Top Safety Pick:

The W221 S-Class models often achieved the 'Top Safety Pick' designation from the Insurance Institute for Highway Safety (IIHS) due to their strong performance in crash tests.

Active Safety Systems:

Anti-lock Braking System (ABS), Electronic Stability Program (ESP), Brake Assist (BAS), ATTENTION ASSIST, tire pressure monitoring system (TPMS), Adaptive Brake Lights.

Adaptive Brake Lights:

Brake lights flash rapidly under heavy deceleration to alert following traffic, a feature detailed in the electrical system section.

Passive Safety Features:

Multiple airbags (front, side, curtain, knee), Active head restraints, advanced crumple zones, high-strength passenger cell, ISOFIX child seat anchors.

Pre Safe System:

Mercedes-Benz's anticipatory occupant protection system that prepares the vehicle and occupants for an imminent collision. Covered in detail regarding its function and diagnostics.

💡 Technology Features

Infotainment System:

COMAND APS (Cockpit Management and Navigation system) with integrated radio, CD/DVD changer, navigation, Bluetooth connectivity, and optional Harman Kardon or Bang & Olufsen surround sound systems.

Voice Control System:

Linguatronic voice control system for operating various functions of the COMAND system, radio, and climate control. Covered in the manual's electronics section.

Instrument Cluster And Displays:

Information on the digital instrument cluster, central display unit, and their diagnostic functions and potential faults.

Driver Assistance Features:

Optional DISTRONIC PLUS (adaptive cruise control with emergency braking), PARKTRONIC (parking sensors), LANE KEEPING ASSIST, BLIND SPOT ASSIST, NIGHT VIEW ASSIST.

Active Park Assist:

Optional system that assists the driver in finding and entering parking spaces. Manual provides operational and diagnostic details.

Connectivity Options:

Bluetooth interface for hands-free calling and audio streaming, optional media interface for connecting external devices (e.g., iPod).

🔧 Maintenance

Scheduled Maintenance Intervals:

Service A/B intervals typically every 10,000 miles or 12 months. More specific intervals for transmission fluid, brake fluid, coolant, and other components are detailed within the manual, often linked to vehicle data (e.g., ASSYST PLUS system).

Brake Fluid Change Interval:

Typically every 2 years or as recommended by the ASSYST PLUS system.

Engine Oil Specification:

MB 229.5 or MB 229.51 approved synthetic oil (e.g., Mobil 1 ESP 0W-40, Castrol Edge 0W-40). Always consult the manual for exact specifications based on engine type and regional requirements.

Transmission Fluid Specification:

MB 236.14 for 7G-TRONIC (722.9) transmissions. Crucial to use the correct fluid to prevent premature wear.

Coolant Specification:

Glycol-based antifreeze/coolant meeting MB 325.0 or MB 326.0 specification (typically blue).

Brake Fluid Specification:

DOT 4 PLUS (MB 331.0) approved brake fluid.

Power Steering Fluid:

Specific hydraulic fluid requirements for the power steering system, usually a Pentosin CHF type or similar approved fluid, depending on specific steering rack configuration.

Common Issues W221 2009:

Coil spring (non-airmatic) breakage, ABC suspension leaks/failures, electronic module failures (e.g., SAM units), thermostat housing leaks (M272/M273), transmission conductor plate issues, A/C blower motor failures, O2 sensor failures, parking brake actuator issues.

Air Suspension Failures:

Common issues with the AIRMATIC air suspension system, including compressor failure, air strut leaks, and sensor malfunctions, with detailed troubleshooting steps.

Oil Filter Part Number Example:

Example for M272/M273 V6/V8: A2721800009 (actual part numbers vary by specific engine variant and may be superseded).

Air Filter Part Number Example:

Example for M272/M273 V6/V8: A2730940501 (actual part numbers vary by specific engine variant and may be superseded).

📚 Vehicle History

Brand Heritage:

Mercedes-Benz has a long and storied history of producing luxury and safety-focused vehicles, with the S-Class line representing its technological flagship for decades. The brand is synonymous with innovation and quality.

Model Evolution W221:

The W221 succeeded the W220 and introduced significant technological advancements, a more imposing design, and enhanced safety features. It was part of Mercedes-Benz's strategy to re-establish the S-Class as the definitive luxury sedan. It received a facelift (MOPF) for the 2010 model year, but this manual covers the pre-facelift 2009 model.

Chassis Code Origin:

W221 designation follows Mercedes-Benz's internal chassis code nomenclature, where 'W' indicates a sedan and '221' is the specific series for this S-Class generation.

Production Period:

W221 generation produced from 2005 to 2013.

🏆 Awards & Recognition

Industry Awards:

The S-Class consistently receives accolades for luxury, technology, and safety from various automotive publications and organizations globally. While specific awards for the 2009 model year are numerous, it's recognized as a benchmark in its segment.