Powertrain:
Engine diagnostics, repair, overhaul, fuel system, ignition system, exhaust system, cooling system, lubrication system for all W221 engine variants (e.g., M272, M273, M156, M275, M279).
Transmission:
Automatic transmission (7G-TRONIC, 7G-TRONIC PLUS) diagnostics, repair, overhaul, fluid specifications, torque converter, mechatronics unit.
Drivetrain:
All-wheel drive (4MATIC) system, rear-wheel drive, differential service, driveshafts, CV joints.
Suspension:
Active Body Control (ABC) system, air suspension (AIRMATIC), hydraulic components, shock absorbers, control arms, bushings, alignment specifications.
Brakes:
Hydraulic brake system, ABS, ESP, SBC (Sensotronic Brake Control where applicable in early models), brake discs, pads, calipers, lines, bleeding procedures, parking brake system.
Steering:
Power steering system, steering rack, tie rods, steering column, steering angle sensor.
Electrical System:
12V and optional higher voltage systems, battery, alternator, starter, wiring diagrams, fuse box locations, lighting systems, horn, sensors, actuators.
Body:
Body construction, interior trim, exterior panels, doors, windows, sunroof, body sealing, corrosion protection, hood, trunk lid.
HVAC:
Automatic climate control, A/C system, refrigerant, compressor, evaporator, condenser, heater core, cabin filter replacement, diagnostic procedures.
Infotainment:
COMAND system, audio components, navigation, Bluetooth, telematics, control modules, speaker diagnostics.
Comfort Features:
Power seats, seat heating/ventilation, massage seats, power mirrors, power windows, ambient lighting, keyless-go system, soft-close doors.
Safety Systems:
Airbag system (SRS), seat belt pretensioners, occupant classification sensors, ADAPTIVE BRAKE, DISTRONIC PLUS, PARKTRONIC, LANE KEEPING ASSIST, BLIND SPOT ASSIST diagnostics.
Scheduled Maintenance:
Detailed service intervals, oil change procedures, filter replacements (oil, air, cabin, fuel), spark plug replacement, brake fluid service, coolant service, transmission fluid service.
Diagnostics Troubleshooting:
System-by-system troubleshooting flowcharts, diagnostic trouble codes (DTCs), symptom-based diagnostics, component testing procedures, use of diagnostic tools (e.g., XENTRY).
Repair Overhaul:
Component removal and installation procedures, engine rebuild specifications, transmission overhaul, suspension component replacement, brake system repair, electrical component repair.
Electrical Diagnostics:
Wiring diagrams for all circuits, component testing, sensor calibration, module programming and coding (where applicable).
Body Repairs:
Panel replacement, door and window adjustments, sunroof servicing, interior trim removal and installation, welding procedures, painting specifications.
Special Tool Procedures:
Use of Mercedes-Benz specific tools for various repair and diagnostic procedures (e.g., ABC system bleeding, engine timing).
Depth:
Comprehensive from basic maintenance to complete engine and transmission rebuilds, including complex electronic systems and hydraulics.
Accuracy:
Authoritative and precise, reflecting factory-level repair standards.
Detail Level:
Includes torque specifications, alignment data, diagnostic flowcharts, electrical schematics, and component testing parameters.
Oil Change Interval:
Typically every 10,000-15,000 miles or 12 months, whichever comes first (depending on engine oil specification and driving conditions).
Major Service Intervals:
Every 20,000-40,000 miles for items like spark plugs, brake fluid, transmission fluid (though some sources recommend earlier transmission service for longevity).
Engine Oil Spec:
MB 229.5 or MB 229.51 (synthetic, e.g., 0W-40, 5W-40, 5W-30 depending on engine and climate).
Coolant Spec:
MB Specification 325.0 (Glysantin G48 or equivalent).
Brake Fluid Spec:
DOT 4 Plus (MB Specification 331.0).
Common Issues Powertrain:
Camshaft magnetic adjuster wear (M272/M273 engines), balance shaft wear, ignition coil failure, early 7G-TRONIC mechatronics issues.
Common Issues Suspension:
ABC suspension leaks, pump failure, hydraulic line issues, airmatic strut leaks, control arm bushing wear.
Common Issues Electrical:
EIS (Electronic Ignition Switch) failure, SAM (Signal Acquisition Module) issues, COMAND system glitches, parking sensor failures.
Common Issues Body:
Water ingress through sunroof drains, trunk seal issues, interior trim rattles.
