The W220 S600 is a flagship V12 sedan with impressive performance but notorious for catastrophic engine failures and complex hydraulic systems that require deep pockets and specialist knowledge to maintain properly.
M275 V12 Engine Failure - Piston/Cylinder Scoring
Common · high severity
Typical onset: 60,000-120,000 mi
Symptoms: Excessive oil consumption (quart per 500-1000 miles), Blue smoke on startup or acceleration, Rough idle and misfires, Metal particles in oil, Loss of compression in one or more cylinders
Fix: The M275 biturbo V12 suffers from piston skirt failures and cylinder wall scoring due to inadequate piston design and cooling. Requires complete engine rebuild or replacement short block. Expect 40-60 labor hours for proper rebuild including removing engine, honing cylinders, replacing all pistons/rings, bearings, gaskets, and timing components. Many shops won't touch it - specialty Mercedes techs only.
Estimated cost: $15,000-25,000
ABC (Active Body Control) Hydraulic Suspension Failure
Common · high severity
Typical onset: 80,000-150,000 mi
Symptoms: Vehicle dropping to bump stops when parked, ABC warning light with 'car too low' message, Hydraulic fluid leaks at struts or lines, Harsh ride quality, Knocking noises over bumps
Fix: The ABC system uses high-pressure hydraulics instead of conventional springs. Struts leak internally, accumulator spheres fail, and the pump wears out. Single strut replacement runs 4-6 hours, but rarely is it just one component. Full system overhaul with all four struts, pump, accumulator, and lines can exceed 25 hours. Parts are shockingly expensive from Mercedes.
Fix: If equipped with Airmatic instead of ABC, the dual air compressor assembly fails due to worn pistons and valves. The unit is under the vehicle near the spare tire location. Replacement is straightforward at 2-3 hours, but the OE pump assembly is expensive. Aftermarket Arnott units are common replacements.
Estimated cost: $1,200-2,500
5-Speed Automatic Transmission Valve Body and Conductor Plate
Occasional · high severity
Typical onset: 100,000-180,000 mi
Symptoms: Harsh or delayed shifts, Limp mode with transmission warning, Slipping between gears, No upshift past 2nd or 3rd gear, Transmission fault codes for solenoids or pressure regulation
Fix: The 722.6 five-speed transmission develops worn valve body bores and failed conductor plate connections. The 13-pin connector is particularly prone to internal shorting. Requires transmission removal, disassembly, and valve body/conductor plate replacement. Figure 12-16 hours total with proper fluid flush and relearn procedures.
Estimated cost: $2,800-4,500
Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 80,000-140,000 mi
Symptoms: Transmission fluid puddles under vehicle, Low fluid level warnings, Burnt transmission fluid smell, Slipping or harsh shifts due to low fluid
Fix: Hard lines and flex hoses to the external transmission cooler crack and leak, especially at crimp fittings. Lines run along subframe and are vulnerable to road debris and corrosion. Replacement involves dropping subframe components for access. Plan 4-6 hours plus fluid refill and leak testing.
Estimated cost: $800-1,500
Front SAM Module (Signal Acquisition Module) Failure
Occasional · medium severity
Symptoms: Intermittent or total failure of power windows, seats, mirrors, Central locking issues, Interior lights malfunction, Random electrical gremlins, Multiple control unit fault codes
Fix: The SAM modules control body electrical functions and fail due to water intrusion (often from clogged sunroof drains or leaking windshield) or internal solder joint failures. Front SAM is behind kick panel. Requires module replacement and coding with Star Diagnostics. Labor is 2-3 hours, but the module itself is expensive and often needs programming from dealer or specialist.
Estimated cost: $1,200-2,200
Crankshaft Position Sensor Failure
Occasional · high severity
Typical onset: 60,000-150,000 mi
Symptoms: No start or crank-no-start condition, Stalling while driving, Intermittent random misfires, Engine cuts out then restarts, Fault codes for camshaft/crankshaft correlation
Fix: On the V12, crankshaft position sensors are located deep in the valley between cylinder banks, requiring significant disassembly of intake components and accessories. This is not a quick roadside fix. Access alone takes 3-5 hours. Sensor itself is inexpensive, but labor kills you. Some techs recommend replacing both cam and crank sensors simultaneously.
Estimated cost: $800-1,600
Owner tips
Change transmission fluid every 40,000 miles regardless of 'lifetime fill' claims - the 722.6 needs it
Keep sunroof drains clear and check footer wells for water - electrical failures often trace to water damage
Use only Mercedes-approved 0W-40 synthetic oil and change every 5,000 miles to maximize V12 life
Budget $3,000-5,000 annually for maintenance and repairs if buying high-mileage - this is not a cheap car to own
Find a specialist independent shop familiar with W220 S-Class before you need one - dealer rates will bankrupt you
Only buy if you have a $10K emergency fund and accept that a major failure will total the car economically - this is a $150K vehicle with $150K repair costs at 1/10th the resale value.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: Located in trunk; AGM battery required for high electrical load of V12 system
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Every control module on the 2000-2006 Mercedes-Benz S600 — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
⚠️ Memory seats, heating, ventilation; adaptation usually successful with aftermarket tools
Fuel Pump Control Module (FPCM)0.6 hr R&Rrelearn only +0.1 hr▸ programming details
📍 Trunk, right side panel near SAM-R
🔧 Star Diagnosis or Autel
⚠️ Controls dual fuel pumps on V12; self-adapts after installation
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2001 Mercedes-Benz S600 5.8L V12 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.