Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Repair and Diagnosis
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View "full tree" with all links on one page (will load slowly, but easier to use ctrl-f to search all pages) [IMAGE: http://127.0.0.1:8080/icons/quick-lookups.svg] Quick Lookups [IMAGE: http://127.0.0.1:8080/icons/locations.svg] Electrical Component Locations Diagnostic Connector (DLC) Locations Electrical Component Locator [IMAGE: http://127.0.0.1:8080/icons/fluids.svg] Fluids [IMAGE: http://127.0.0.1:8080/icons/technical-service-bulletins.svg] Technical Bulletins Campaigns Technical Service Bulletins [IMAGE: http://127.0.0.1:8080/icons/tire.svg] Tire Fitment [IMAGE: http://127.0.0.1:8080/icons/diagrams.svg] Wiring Diagrams System Wiring Diagrams Using lemon2025'S System Wiring Diagrams Accessories & Equipment Cruise Control Systems Gauges & Instrument Panels Adjustable Outside Mirrors Wiper/Washer Systems Body & Frame Adjustable Outside Mirrors Brakes Anti-Lock Brakes Anti-Lock Brake System Mechanical - Hydraulic Disc Traction Control Anti-Lock Brake System Drivelines & Axles Axle Shafts Differentials & Drive Axles - Rear Electrical Charging Systems 1989-90 Electrical - Alternators & Regulators - 190E, 260E, 300CE, 300E, 300SE, 300SEL, 300TE, 420SEL, 560SEC, 560SEL, 560SL Component Locations Diagnostic Connector (DLC) Locations Electrical Component Locator 1983-93 Fuses & Circuit Breakers - 380SL & 560SL Gauges & Instrument Panels Starter Wiring Diagrams System Wiring Diagrams Using lemon2025'S System Wiring Diagrams Engine Mechanical Auxiliary Emission Control Systems Emission Control System Visual Inspection Procedures - General Information Engine Mechanical - V8 Starter Engine Performance Adjustments Application Engine Performance Emissions EGR Function Testing - MERCEDES-BENZ Emission Applications Emission Control Abbreviations State Emission Standards - Diesel State Emission Standards - Gas Remove, Overhaul & Install Remove/Install/Overhaul Sensor Range Charts Specifications System Basic Testing EGR Function Testing System/Component Tests Tests W/Codes Tests W/O Codes Testing & Diagnosis Basic Testing EGR Function Testing System/Component Tests Tests W/Codes Tests W/O Codes Theory and Operation Theory/Operation Vacuum Diagrams Wiring Diagrams General Information Abbreviations Commonly Used Abbreviations - General Information Emission Control Abbreviations Basic Trouble Shooting Basic Trouble Shooting - General Information Commonly Used Abbreviations - General Information Emission Control Abbreviations Engine Performance - Trouble Shooting - General Information Brakes Anti-Lock Brake Safety Precautions - General Information Map - Brake Systems Map - Routine Inspection Reference Guide Check Lists Symptom Check List Worksheet - General Information Computer Relearn Procedures Driveline/Axles Drive Axle Noise Diagnosis - General Information Gear Tooth Contact Patterns - General Information Map - Drive Train & Transmission Trouble Shooting - Clutches - General Information Electrical Map - Electrical Systems Using lemon2025'S System Wiring Diagrams Engine Engine Overhaul Procedures - General Information General Cooling System Service - General Information Engine Performance Electrostatic Discharge Warning - General Information Engine Performance Diagnostic Routine Outline - General Information Engine Performance Safety Precautions Map - Engine Performance & Maintenance Parasitic Load Explanation & Test Procedures - General Information State Emission Standards - Diesel State Emission Standards - Gas Waveforms - Injector Pattern Tutorial - General Information Map - Exhaust Systems Heating, Ventilation & A/C (HVAC) Map - Heating, Ventilation, & Air Conditioning Identification CANADIAN Model Cross-Reference MERCEDES-BENZ Model Identification Metric Conversions Engine Displacement Conversion Table - ECAT Metric Conversions OEM General Information MERCEDES-BENZ Model Identification Maintenance Reminder Light (Reset Procedures) Restraints Air Bag/SRS Component Inspection & Replacement Tables - EUROPEAN Steering Map - Steering, Suspension, Wheel Alignment, Wheels & Tires Wheel Alignment Theory & Operation - General Information Trouble Shooting - Manual Transmission - General Information Heating, Ventilation & A/C (HVAC) General Servicing A/C Compressor Application & Specifications A/C Compressor Oil Checking A/C Compressor Servicing A/C System General Diagnostic Procedures A/C System Precautions HVAC Control Systems A/C-Heater System - Automatic Maintenance Procedures Maintenance Information Maintenance Reminder Light (Reset Procedures) Service Indicator & Warning Lights Restraints Air Bag, SRS Air Bag Restraint Systems Air Bag/SRS Component Inspection & Replacement Tables - EUROPEAN Steering Manual Steering Power Steering Steering Column Suspension Front Suspension Suspension - Front Rear Suspension Suspension - Rear Wheel Alignment Jacking & Hoisting Pre-Alignment Checks Riding Height Adjustment Specifications & Procedures Transmission Automatic Trans 1989-90 Transmission Servicing - Transmission Removal - 260E, 300CE, 300D, 300E, 300SE, 300SEL, 300TE, 420SEL, 560SEC, 560SEL, 560SL Overhaul - W4A020 & W4A040
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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