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Mercedes-Benz S-Class S 320 CDI Prestige common faults.

2002–2005, saloon, diesel, 204 HP.

The fault list covers: OM648DE32LA engine, MB7226 transmission.

What you save stays on this device only. My saves

2 fault write-ups. Both are important. No recall on the list.

If you know the year, pick it. Faults for other years drop out of the list.

Before you buy

Known faults

2 important faults

Airmatic air suspension: leaking air spring, overworked compressor

expensive

The Mercedes Airmatic system holds the ride height with air springs and electronically controlled dampers. The most common faults over time are the relay, the compressor and a leaking air spring or air line.

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The rear air springs of the 2003 to 2009 E-Class (W211) are particularly prone to leaking along the clamps. If the system leaks, the compressor runs continuously, overheats and fails, so an unrepaired leak takes the compressor with it.

Symptoms: one corner of the car sinks by morning, an "Air Suspension" or level control fault message, and compressor noise while standing. It was an option (or standard) across several generations from the W220 S-Class onwards; the estate E-Class often has air springs with level control on the rear axle as standard.

between 100,000 and 220,000 km

What to check

  • In the morning, before setting off, look at all four corners: an uneven stance means a suspected leak
  • With the car standing, listen to the compressor: continuous running indicates it is overworked
  • Ask for a fault code read on the suspension controller (level and pressure sensor codes of the C1132 / C1144 kind)
3 more steps in the write-up

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.

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The early cars (1995 to 2001) had planetary gear and freewheel wear; after 1998 to 2001 the design improved, and on the used market the W203/W211/W220 era is the typical find.

between 120,000 and 250,000 km

What to check

  • Try it cold and warm: jerking or delayed shifts are suspect
  • Look at the colour and smell of the ATF: burnt oil points to wear, and a "milky" emulsion means antifreeze in the ATF
  • Ask for a fault code read on the gearbox controller
2 more steps in the write-up

Checklist

Mercedes-Benz S-Class S 320 CDI Prestige

First what you would check on any car. Then the faults of this model.

Before you buy

Checklist

The printed sheet starts with what you would check on any car. What you tick stays on this device only.

On every car

Ask the owner

Faults of this model

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Engine and transmission

OM648DE32LA

150 kW (204 HP) · diesel

MB7226 · 5G-Tronic, longitudinal (Mercedes 722.6 / NAG1)

automatic · 5 speed

Torque limit600 Nm
MakerMercedes-Benz

We built the code from the model and the gear count. The factory sheet does not state it.

Variant data

What is in this version

Factory data

Trim
S 320 CDI Prestige
Body
saloon
Fuel
diesel
Transmission
automatic
Engine size
3222 cc
Power
150 kW (204 HP)
Drive
RWD
Production
2002–2005

Factory service interval

The manufacturer specifies this for this version. Of the mileage and the time, the one that comes first is the one that counts.

  • Air filter

    • 60,000 km or 4 years

  • Cabin (pollen) filter

    • 30,000 km or 2 years

  • Brake fluid change

    • first: 3 years, then 2 years(first change at 3 years, then every two years)

  • Fuel filter, diesel

    • 60,000 km or 2 years
All W220 versions

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