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P2459: Diesel particulate filter regeneration frequency

The diesel particulate filter is regenerating more often than normal. Usually the engine makes too much soot or a sensor reads wrongly.

Code P2459 at a glance
CodeP2459
SystemEngine and transmission
GroupP24xx, EGR, EVAP and particulate filter
TypeGeneric: it means the same on every make
Can you keep driving?With care

What P2459 means

The ECU keeps track of how often it needs to regenerate, that is, burn off the soot in the particulate filter. If regenerations come far closer together than expected, something is filling the filter too fast, or the ECU thinks it is full when it is not.

Most common causes

  • Differential pressure sensor or its pipes giving falsely high readings
  • Engine producing excess soot: leaking injector, dirty EGR or intake leak
  • Lots of short trips leaving regenerations half done
  • Oil consumption fouling the filter
  • High ash load in the filter

Symptoms

  • Engine warning light on
  • Fan running or high idle after switching off, often
  • Higher fuel consumption
  • Oil level rising (fuel from regenerations dilutes it)

Can you drive with P2459?

With care You can drive, but have it checked soon: frequent regenerations use extra fuel and can dilute the engine oil with diesel, which is bad for the engine.

How to check it

Check the oil level on the dipstick: if it is above maximum or smells of diesel, tell the garage. On your scanner, compare the estimated soot load just before and after a regeneration.

How to read and clear P2459 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P2459 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P2459 is a generic code, so it means the same on any make, for example on BMW, Ford, Mercedes-Benz, Renault, Volkswagen, Volvo. See what Final OBD does on your car in makes and models.

What does code P2459 mean?

The ECU keeps track of how often it needs to regenerate, that is, burn off the soot in the particulate filter. If regenerations come far closer together than expected, something is filling the filter too fast, or the ECU thinks it is full when it is not.

Can you drive with P2459?

You can drive, but have it checked soon: frequent regenerations use extra fuel and can dilute the engine oil with diesel, which is bad for the engine.

How do you clear P2459?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P2459 comes back.