Mercedes-Benz P2002

DPF efficiency on Mercedes diesels — OM651 and OM642 engines suffer carbon-blocked EGR cooler that fouls the DPF prematurely.

Mercedes-Benz P2002 — DPF efficiency on Mercedes diesels — OM651 and OM642 engines suffer carbon-blocked EGR cooler that fouls the DPF prematurely. Typical UK independent garage cost: £280–£2400.

What actually causes P2002 on a Mercedes-Benz

On the OM651 the EGR cooler internally cracks and dumps coolant into the intake — coolant mixes with soot and forms a sludge that blocks the DPF and inlet ports. Replacing the DPF without addressing the EGR cooler is futile. The OM642 has a separate well-known intake manifold swirl flap failure that drops a metal flap into a cylinder — catastrophic.

Mercedes-Benz engines that log P2002

• OM651 2.1 CDI (C-Class W204/W205, E-Class W212, Vito, Sprinter)
• OM642 3.0 V6 CDI (E350, ML350, Sprinter 519)

How we diagnose P2002 on a Mercedes-Benz

1. Pressure-test EGR cooler — coolant loss with no external leak = internal cooler failure
2. On OM642 inspect intake manifold swirl flap motor and linkage
3. Read DPF soot and ash mass on STAR / XENTRY
4. Plan EGR cooler + DPF together if cooler has failed

The common misdiagnosis to avoid

Insist on EGR cooler pressure test (and intake manifold inspection on OM642) before authorising any DPF work on Mercedes diesels. We've seen £2,000 DPFs ruined inside 8,000 miles by an unaddressed EGR cooler leak.

Mercedes-Benz P2002 repair cost in the UK

Expect £280–£2400 including parts and labour at an independent garage. Main-dealer quotes on Mercedes-Benz are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.

Bob's workshop tip

If you buy a used C-Class or E-Class OM651, budget for an EGR cooler at some point — they almost all do it. Updated coolers with revised internals are now available.

Codes usually seen alongside P2002 on Mercedes-Benz

• P244A
• P244B
• P0401
• P2463

Symptoms drivers report with P2002

• The 'Engine Service Now' message on the dash, often without a limp mode initially.
• Thick black soot deposits around the inside of the tailpipe (it should be clean enough to eat off).
• A heavy smell of diesel fumes inside the cabin when sitting at traffic lights.
• The car seems to perform fine but the 'DPF Full' warning keeps popping up every 50 miles.
• Excessive cooling fan noise because the car is constantly trying (and failing) to start a regeneration.

Repairs that clear P2002

• Static regen on scan tool
• Replace pressure sensor
• Injector leak-off test
• Chemical DPF clean, replace if blocked >80%

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P2002 guide.