Segment:
Compact Executive Sedan (W203 Generation)
Target Audience:
Owners seeking DIY repairs, independent repair shops, certified Mercedes-Benz technicians.
Competitors:
BMW 3 Series (E46), Audi A4 (B6), Lexus IS300, Acura TL
Premium Appointments:
High-quality interior materials, advanced safety features, refined ride comfort.
Powertrain:
Smooth and potent 3.2L V6 engine paired with a responsive 5-speed automatic transmission.
Engineering:
Mercedes-Benz engineering hallmarks: safety, durability, and performance.
Engine:
M112.954 V6 Engine (3.2L) - Maintenance, Diagnostics, Repair, Overhaul
Transmission:
5G-TRONIC Automatic Transmission (722.6) - Operation, Maintenance, Diagnostics, Repair
Drivetrain:
Rear-Wheel Drive (RWD) System, Driveshafts, Differential
Suspension:
Front and Rear Suspension Systems (MacPherson Strut Front, Multi-Link Rear), Shock Absorbers, Springs, Bushings
Brakes:
Front and Rear Disc Brakes, ABS (Anti-lock Braking System), ESP (Electronic Stability Program), Brake Fluid Specifications, Bleeding Procedures
Steering:
Power Steering System, Steering Column, Wheel Alignment Specifications
Electrical System:
Battery, Charging System, Starter, Ignition System, Lighting, Fuses, Relays, Wiring Diagrams
Engine Management:
ME 2.8 Engine Control Module (ECM), Fuel Injection, Ignition Timing, Sensors (MAP, MAF, O2, Crankshaft, Camshaft), Emission Controls
Climate Control:
Automatic Climate Control (AAC), HVAC System Components, Refrigerant Handling, Diagnostics
Body And Interior:
Body Panels, Doors, Hood, Trunk, Bumpers, Interior Trim, Seats, Airbags
Safety Systems:
Airbag System (SRS), Seatbelt Pretensioners, Crash Sensor Diagnostics
Comfort And Convenience:
Power Windows, Power Locks, Remote Keyless Entry, Sunroof Operation
Maintenance:
Oil Changes, Filter Replacements, Spark Plug Replacement, Fluid Flushes (Coolant, Brake, Transmission), Belt Replacement
Troubleshooting:
Diagnostic Trouble Codes (DTCs), Symptom-Based Diagnostics, Component Testing
Repair:
Engine Component Replacement (Alternator, Starter, Water Pump, Ignition Coils), Transmission Service, Brake Pad/Rotor Replacement, Suspension Component Replacement, Electrical Component Diagnosis and Replacement
Rebuilds:
Engine and Transmission Overhaul Procedures
Calibration:
Steering Angle Sensor Calibration, Electronic Throttle Body Adaptation
Depth:
Comprehensive: From routine maintenance to advanced diagnostics and complete mechanical and electrical system overhauls.
Diagnostics:
In-depth diagnostic procedures using OBD-II scanners, including specific Mercedes-Benz diagnostic codes and strategies.
Wiring Diagrams:
Detailed electrical wiring schematics for all major systems, crucial for electrical troubleshooting.
Torque Specifications:
Precise torque values for all critical fasteners, ensuring proper assembly and preventing component damage.
Special Tools:
Identification and usage of specialized tools required for specific repair procedures.
Engine Type:
V6, SOHC (later M112 variants often had 3 valves per cylinder, but the core M112 is 2 valves per cylinder, though some sources might list 3 for specific implementations)
Displacement:
3.2 Liters (3199 cc)
Bore X Stroke:
89.9 mm x 84.0 mm
Compression Ratio:
10.0:1
Valvetrain:
Single Overhead Camshafts (SOHC) per bank, 2 valves per cylinder (typical for M112.954 variant)
Horsepower:
215 hp @ 5750 rpm
Torque:
229 lb-ft @ 3000-4500 rpm
Fuel Delivery:
Electronic Fuel Injection (Sequential Multi-Point)
Fuel Type:
Premium Unleaded Gasoline (91 Octane Recommended)
Ignition System:
Distributorless Electronic Ignition (Two spark plugs per cylinder)
Coolant Type:
Mercedes-Benz approved G48 (Ethylene Glycol based) or equivalent
NHTSA Front Impact:
5 Stars (Driver and Passenger)
NHTSA Side Impact:
4 Stars (Front and Rear Passengers)
ABS:
Standard Anti-lock Braking System
Esp:
Standard Electronic Stability Program
Traction Control:
Standard Acceleration Slip Regulation (ASR)
Airbags:
Front Dual Stage Airbags, Front Side Airbags, Window Airbags (Standard)
Seatbelts:
Front 3-Point Active Seatbelts with Pretensioners and Force Limiters
Oil Change Interval:
Approximately every 10,000 miles (16,000 km) or 12 months, based on 'flexible' service intervals (Assyst system).
Major Service A:
Service A typically around 10,000 miles (includes oil and filter change, tire rotation, etc.)
Major Service B:
Service B typically around 20,000 miles (includes Service A items plus cabin air filter, brake inspection, etc.)
Engine Oil Type:
MB 229.5 Approved Synthetic (e.g., Mobil 1 0W-40, Castrol Syntec 0W-30)
Engine Oil Capacity:
8.5 quarts (8.0 liters) with filter
Coolant Capacity:
Approx. 8.7 quarts (8.2 liters)
Brake Fluid Type:
DOT 4 Plus (or MB-Approval 331.0)
Ic Module Failure:
Intermittent electronic issues related to the Instrument Cluster (IC) module.
Mass Air Flow Sensor:
Potential for MAF sensor malfunction leading to rough idle or poor performance.
Oil Cooler Seals:
Leaking oil cooler seals can lead to oil in the coolant or vice versa.
Window Regulator Failure:
Common failure of power window regulators, especially in older units.
