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Mercedes-Benz C-Class W203 common faults.

2000–2007. The fault list covers this generation and the engines in it. If the listing gives the exact version, pick it below.

Mercedes-Benz C-Class W203

M 93 / CC BY-SA 3.0 de

What to watch for

What can go wrong on this car?

The list covers the generation, the engines and the transmissions. Once you pick the version, only the faults that apply to it stay.

critical7

M272 V6: early wear of the balance shaft gear

critical

On the M272 V6 petrol engines sold between 2004 and 2007 (with engine numbers below 2729..30 468993) the balance shaft gear wears out early.

Applies to the engine M272E25, M272E30, M272E35.

OM646 2.1 CDI: a snapping timing belt

critical

Many OM646 owners do not know that this engine has a timing belt, not a timing chain.

Applies to the engine OM646DE22LA, OM646DE22LALR.

Repair: 500–1,400 EUR

expensive1

5G-Tronic (722.6): control unit in oil, coolant in the ATF

expensive

The Mercedes 5 speed 722.6 automatic (5G-Tronic / NAG1) has three faults that also recur on the used market: (1) the control electronics sit inside the gearbox housing, and a leaking connector lets oil onto the electronics; (2) cooling faults around 2003 (and later) can let antifreeze into the ATF, which shortens its life; (3) wear of the torque converter lock-up clutch contaminates the valve body and causes jerky shifts.

Applies to the transmission MB7226.

12 more faults belong to this generation. On the version page, only the ones that apply stay.

Official recall5 recallsShow

The manufacturer fixes these for free at a franchised dealer. Ask with the VIN whether it was done. The list covers the whole generation. We did not filter it by model year. Some apply only to a narrower production window.

A12/00280/20Safety recallInjuriesno date · EU Safety Gate

The adhesive bond between the glass panel and the sliding-roof frame may not meet the specifications. As a result, the glass panel could become completely detached from the vehicle, posing the risk to the following traffic.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/00391/23Safety recallInjuriesno date · EU Safety Gate

Due to improper adhesive bonding of the glass panel to the sliding roof frame, the panel may detach from the moving vehicle, creating a risk of an accident, injuries. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/01236/20Safety recallInjuriesno date · EU Safety Gate

The driver and passenger airbags of the company Takata in vehicles with ammonium nitrate gas generators without drying agents could, under certain climate conditions, lead over time to a chemical change in the fuel. In the event of an accident triggering the release of the driver or passenger airbag, this change could cause the gas generators to burst. If a gas generator ruptures, the airbag would then have no restraining function and loose parts from the gas generator could reach the vehicle interior. This would increase the risk of injury for passengers.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/01448/22Safety recallEnvironment, Injuriesno date · EU Safety Gate

Faulty configurations of the control units (traction systems, signal recording triggering modules, engine control units and headlights) could cause one or more control units to malfunction, which could increase the risk of an accident. The exhaust emissions exceed the legal limits, posing a risk to the environment. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/0457/17Safety recallInjuriesno date · EU Safety Gate

Following the update of the control unit coding, the coding parameters of the control unit could be defective. This could give rise to various unplanned reactions in the vehicle: the wrong airbag could be triggered in the event of an accident, the airbag control unit may not recognise the belt buckle status, the engine control unit could be coded with a false maximum speed or various assistance systems may not function.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

Engines and transmissions in this generation

A fault is often tied to the engine, not to the whole generation. You find the engine code in the registration document.

W203 · 2000–2007

Pick the version.

The fault list opens on the version page.

270 versions

Showing 60 of 270 versions.

Neighbouring generations

W203 · 2000–2007

W203 (2000-2007). If the listing is from the changeover year, look at the neighbour too.

Previous generation

This is the earliest.

This generation

W203 · 2000–2007

Next generation

W204 · 2007–2014

Common questions

About this generation

Which years does this page cover?

2000–2007. The changeover year can fall in two generations. If the listing is from that year, look at the neighbour too.

Does the fault apply to every car like this?

No. It depends on the engine and the transmission too.

Is it free?

The fault list is.

Information, not an expert opinion

We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.

  • A fault on the list does not mean the car you are looking at has it.
  • A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
  • You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.
Details in the terms