Car Model Guide/ Mercedes-Benz/ E-Class/ S211/ E 220 CDI

E 220 CDI OM646

The four-cylinder diesel that carried the W211, and a durable one. Bottom ends go a very long way, so the money is in the injectors and the emissions hardware. The later 170 PS version is the one worth finding.

Overview

The E 220 CDI is the OM646 diesel version of the Mercedes-Benz E-Class wagon (S211), sold 2003–2009 with 170 PS and manual or automatic. Demands diligence at level 3. The engine itself is durable. The risk on an early car is the Sensotronic brake system, which is expensive and not optional. 15 failure modes are recorded against its engine, gearbox, chassis and shared components, one of which is a walk-away item without documented proof. Prices on this page are illustrative placeholders rather than a sourced market sample. See the methodology for how the bands are derived.

Mercedes-Benz E-Class wagon (S211) · photo Mercedes-Benz E 220 CDI T-Modell (S211, 2008) (53046907823) by Charles from Port Chester, New York · CC BY 2.0 · Wikimedia Commons

Power170 PS

Torque400 Nm

Years2003–2009

Fueldiesel

DriveRWD

EnginesOM646

Biggest risks

Ranked by probability × repair cost. 15 recorded in total.

40Fragile

Sensotronic brake unit failure (pre-facelift)€1,200–€2,500partly checkablewalk away
Corrosion at the arches, boot and tailgate€300–€2,500checkable
DPF clogging and forced regeneration€250–€1,800partly checkable

Risk level −22 · Walk-away failures −12 · Likely spend vs price −26 · all issues →

System by system9 systems reviewed · 2 with no recurring fault reported

Engine✓ clearNo recurring fault reported for this system on this engine.

Fuel systemwatchInjector seat leaks and seized injectors, €400–€1,200.

Intake & air✓ clearNo recurring fault reported for this system on this engine.

CoolingwatchCoolant expansion tank cracking, €120–€250.

Emissions⚠ attentionDPF clogging and forced regeneration, €250–€1,800.+1 more in this system

Transmissionwatch7G-Tronic conductor plate and 13-pin connector leak (722.9), €400–€900.+1 more in this system

ElectricswatchFootwell module (FRM) failure, €150–€700.+2 more in this system

Suspension & brakes⚠ attentionSensotronic brake unit failure (pre-facelift), €1,200–€2,500. Walk away without proof.+3 more in this system

Body & interior⚠ attentionCorrosion at the arches, boot and tailgate, €300–€2,500.+1 more in this system

Pre-facelift or facelift, this engine spans both

The same badge either side of the changeover. Bands are split at the facelift year from the generation record.

Phase	Years	Low	Average	High	Good buy	What differs
pre Pre-facelift	2003–2005	€2,550	€4,100	€6,850	€3,350	The specification the car launched with.
LCI Facelift (LCI)	2006–2009	€2,800	€4,500	€7,500	€3,650	Sensotronic brake-by-wire dropped; Revised lights and interior; OM642 replaced the OM648 in the E 280 and E 320 CDI

Known issues, ranked by expected cost

Faults recorded against this engine, its components and its chassis, ranked by likelihood × repair cost. Costs are indicative ranges with a stated labour basis.

Sensotronic brake unit failure (pre-facelift)E-Class platform€1,200–€2,500

A red brake warning, a message telling you to stop, a much harder pedal, and in some cases the car limiting itself. The electro-hydraulic Sensotronic unit has a pump and accumulator with a counted service life, and once the counter expires the system demands replacement. Mercedes dropped the system at the 2006 facelift, so later cars aren't affected.

Check: Establish the build date first, since facelift cars don't have it. On an earlier car, have the SBC counter read on a diagnostic and treat a high count as a bill you're about to inherit.

Later parts: Conventional hydraulic brakes from the 2006 facelift

BrakescommonPartly detectablewalk away without proofevidence: manufacturer100–200k km

Corrosion at the arches, boot and tailgateE-Class platform€300–€2,500

Bubbling paint at the rear arches and around the boot lid or tailgate, and rust in the spare wheel well. This generation was built during Mercedes' worst period for corrosion protection, and cars in salted climates suffer. Later cars are better than early ones, but the body is worth more attention here than on a W212.

Check: Look along the rear arches and the boot or tailgate seams in good light, lift the boot floor, and check underneath for previous repair.

Body & corrosioncommonDetectable at viewingevidence: documented

DPF clogging and forced regenerationDPF€250–€1,800

Warning light, limp mode, oil level rising above the maximum mark from fuel dilution. The filter needs sustained hot running to regenerate. A car used for short urban trips never completes a regeneration cycle.

Check: Read the DPF soot load and the distance since the last regeneration on a scan tool, and check the engine oil level and smell it for diesel. Ask what the car was used for. A short-trip city diesel is the wrong car regardless of mileage.

EmissionscommonPartly detectableevidence: documented120–250k km

Front control arm bushing wearE9x chassis€300–€700

Knocking over bad surfaces, vague or wandering steering, uneven front tyre wear, steering shimmy under braking. The front lower arm bushings are a known wear item on this chassis and go well before the ball joints.

Check: Drive over a rough road at low speed with the windows down and listen. Check the inside edges of the front tyres for feathering.

SuspensionuniversalDetectable at viewingevidence: documented80–150k km

Injector seat leaks and seized injectorsOM646 2.1 CDI€400–€1,200

A chuffing noise from the engine bay, a diesel smell in the cabin, and black carbon deposits building up around the injector. The copper seat washer fails and combustion gases leak past the injector, carbonising the seat. Left alone the injector can seize in the head, and extraction then becomes the expensive part of the job.

Check: Look for black tarry deposits around the injectors with the cover off, and listen for a rhythmic chuffing at idle.

FuelcommonDetectable at viewingevidence: documented150–280k km

7G-Tronic conductor plate and 13-pin connector leak (722.9)Mercedes 7G-Tronic seven-speed automatic (722.9)€400–€900

Harsh, delayed or jerky shifts, holding a gear then banging the next in, and limp mode, often with speed-sensor or gear-ratio fault codes. The speed sensors in the conductor plate (mechatronic) fail, and/or the external 13-pin connector leaks fluid that wicks up the wiring into the control unit. Early units are the most affected.

Check: Test-drive through every gear cold and warm. Scan the transmission, and pull the external 13-pin plug to check for fluid on the pins.

TransmissioncommonPartly detectableevidence: documented120–220k km

Run-flat tyres and kerbed or cracked wheelsE9x chassis€150–€900

Harsh ride, vibration at speed, slow punctures. Stiff-sidewall run-flats transmit impacts straight into the rim, and these alloys crack rather than bend.

Check: Inspect the inner rim edge of every wheel for cracks and hairline splits, not just the face for kerbing. Budget for a set of conventional tyres; most owners switch and the ride improves markedly.

SuspensioncommonDetectable at viewingevidence: documented

Corrosion at the rear subframe and arch seamsE9x chassis€300–€2,000

Bubbling at the rear arch lip, scaling on subframe mounting points and rear suspension components. Age plus road salt. This generation isn't a notorious rotter, but nothing from 2005–2013 is immune in a salted market.

Check: Put it on a lift and look at the rear subframe mounting points and the arch lips from behind. Largely a non-issue on cars from southern Europe, a real one on northern and Baltic cars.

Body & corrosionoccasionalDetectable at viewingevidence: documented

Ranked by probability × repair cost, not by how loudly a failure is discussed. Inherited from the engine, gearbox, chassis and shared components, each written once. All 15 issues in full →

Mileage and servicing

What the odometer does and doesn't tell you here, plus the service items whose neglect causes the expensive failures above.

These were taxis and company cars, so very high mileage with a full book is normal. Build date matters more than distance, because it tells you which brake system is fitted.

Service item	Interval	Cost
Sensotronic brake unit A failed SBC pump is the biggest single bill on this car	on pre-2006 cars, check the counter	€1,200–2,500
Engine oil The basis of this engine's long life	on time, correct spec	€110–160
Injector seals Leaking seats carbon up and seize the injectors	if it chuffs or smells of diesel	€400–1,200

What to pay

What this engine sells for, against the median of every engine in the chassis. All figures are illustrative placeholders. See the basis chips.

median €4.3k

€2.5k€3.4k€7.5k

Cheapfind the reasonGood buyif it checks outFairnormal moneyOverpricedneeds justifying

Asking price (€)Mileage (km)

Enter an asking price to get a verdict against this variant's band: cheap, fair, good buy or overpriced.

United States vs Europe

1 EUR = 1.08 USD · 2026-07

🇪🇺 Europe · EUR€3,350band €2,550–€7,500

🇺🇸 United StatesNot soldE 220 CDI OM646 was never a US-market car

What that meansNo US band exists to compare. Any car you find there's a private import, parts and specialist knowledge are thinner, and the price says more about import cost than about the market.

US figures are the EU band converted at a stated rate. No US market differential is modelled: we hold no sourced US asking prices, and inventing one would be worse than saying so. What the comparison does show for real is availability. Most of this range was never sold in the US.

ModelMercedes-Benz E-Class E 220 CDI
ChassisS211
EngineOM646
Years2003–2009
MarketCentral EU
Windowrolling 12 months to 2026-07

Good buy at or under the marker · Median asking price · bar spans the 10th to 90th percentile · dashed line is the s211 median, all 4 engines

Good buy isn't the same as cheapest. Any car without documentation for sensotronic brake unit failure (pre-facelift) should be priced as if the repair is still owed. Full breakdown by facelift phase →

Buyer notes

Our judgement, kept separate from the records it's built on.

Our read, not a record

The OM646 four is one of the more durable diesels of its era and it will run to enormous mileages on regular servicing. The question that decides the car isn't the engine at all, because it's the brakes. Sensotronic, fitted to pre-facelift cars, is an electro-hydraulic system whose pump fails and costs four figures to replace. Facelift cars from 2006 dropped it for a conventional setup, which is why they're worth the premium. So find a later car, check the injectors and the emissions hardware, and look hard at the arches for rust.

Everything above this line comes from the issue and specification records. This paragraph is our judgement on top of them. See how we reach it.

Full specification

Manufacturer figures for this engine and body, as recorded in the variant and engine data.

Engine code	OM646 2.1 CDI
Configuration	I4, turbocharged · 2148 cc
Fuel / injection	diesel · common rail
Model years	2003–2009
Facelift phase	Sold either side of the 2006 facelift, 2003–2005 pre, 2006–2009 LCI
Power / torque	170 PS · 400 Nm
Transmissions	6-speed manual · 5-speed automatic (5G-Tronic) · 7-speed automatic (7G-Tronic)
Gearbox families	Mercedes 5G-Tronic five-speed automatic (722.6) · Mercedes 7G-Tronic seven-speed automatic (722.9)
Drivetrain	RWD
Economy (real-world)	5.5–7 l/100 km mixed
Markets	EU

E 220 CDI OM646

Overview

Pre-facelift or facelift, this engine spans both

Known issues, ranked by expected cost

Pre-purchase inspection

1Static checksEngine off, ideally on a lift.

2On the driveInclude low-speed manoeuvring, not just an open road.

3PaperworkOn these cars the folder is most of the value.

4OBD scanMandatory. A seller who refuses a scan has answered the question.