My car is a Hyundai i30 1.6 CRDI diesel from 2009. At the moment it suffers from fault P2002 which causes the car into limp mode. There has also been fault P1406 for a longer time, but this didn't cause any problems.

Some history: I bought the car in 2015. A half year later I chiptuned the car myself (WinOLS/MPPS) and a while after that I had the DPF emptied by a professional tuner. The latter included 'writing away' the DPF in the software. (I have saved all software files before and after tuning and DPF removal). After this the car has run fine for years. About a year ago the turbo was blown. Luckily I could have it repaired. A new turbo was installed. The mechanic mentioned that a lot of oil had come into the engine, but he was able to clean it out. The car ran fine again after this, although maybe a little less powerfull than before. A few months ago the car had its anual test and this time it failed the emissions test, so a new DPF had to be installed again. The car still ran fine, but a few weeks later I realized it was still running on the software for a deleted DPF. This could prevent the DPF from regenerating, so I installed the software for an active DPF again. Since that time the P2002 faults appeared.

I already searched for the error code and found there can be many reasons:

  • A clogged DPF. Unlikely, as it is a brand new one. Or is a month without regeneration enough to clog it?
  • Faulty pressure sensor. I've already tried a new one, and this didn't help (These things are cheaper than the hour rate of a professional mechanic, so it was worth a shot.)
  • Clogged EGR system?
  • Leaky hoses?
  • Anything else?

I'm not a professional mechanic; I can only do so much myself. Changing a pressure sensor is a piece of cake, but things like disassembling the entire EGR system or anything that involves crawling under the car is beyond my capabilities.

I'd like to know if there are still things I can check myself before I take the car to a mechanic. Especially if the combination of P2002 and P1406 could indicate anything.

2 Answers 2


When a diesel ECM detects a pressure differential before and after a DPF, and if that differential exceeds a certain threshhold, it will begin a DPF regeneration as soon as exhaust temperature, speed and load conditions allow.

That threshhold occurs when the DPF is nearly "full". For one of my vehicles, the threshhold is at 80% "full".

If the regeneration fails to occur because the software controlling regeneration has been modified, the DPF will become 100% "full", the ECM will throw a code and the engine will enter limp mode. Even without limp mode, the engine will have reduced power due to back pressure in the exhaust.

If you restore the software to its original program and you have a scan tool that can force a regeneration (or if a dealer forces the regeneration) then you may save the DPF from the scrap heap. If it is so clogged that regeneration does not work, you'll need a new DPF.

Is one month without regeneration enough to clog a DPF? Yes, absolutely, no question about it.


Hm, this doesn't look like a brand new one at all to me. That could explain a lot. A solution to the problem has not yet been found, but a clogged DPF seems more plausible now.


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