Wikipedia: Diagnostic Trouble Code (DTC)
All following DTCs are Subaru specific, applicable to closed-type DPF Boxer Diesel models only, Euro 4, 5, 6 emission standards.
Some of these DPF related DTCs trigger DPF light flashing.

ID Name Comment
P1465 DPF Particulate Overfill
P1466 DPF Substrate Damaged (E4: never gets set?)
P1467, P242F DPF Ash Overfill ≥ 100 %
P1468 Oil Dilution ≥ 10 % ; also see Distance to Oil Change
P1469, P246C DPF Limp-Home Mode Reduces injection quantity and power.
P1471 DPF Pressure Difference Sensor Upstream Piping Trouble (E4: never gets set?)
P1472, P2454 DPF Pressure Difference Sensor (Low)
P1473, P2455 DPF Pressure Difference Sensor (High)
P147B Catalytic Converter and DPF
P2453 Particulate Filter Pressure Sensor “A” Circuit Range/Performance

Related ROM code has not been analyzed completely yet, no guarantees as usual. It is definitely much more sophisticated compared to Subaru petrol ROMs.


  • 2016-10 Added DPF related Euro 6 DTCs.

5 responses to “DTCs

  1. What could P1472 be caused by?
    Was lit a couple miles, then didnt show next engine turn on.

    A couple miles more and DPF started the forced regen.
    Drove as per instructed, light went off. Then on again, once again drove as instructed but this time the DPF went into P1469 and flashing DPF light.


  2. Hi,
    I have a 2009 euro 4 diesel impreza. I have had a lot of issues with the car since we got it but recently the dpf light keeps coming on so i reset using rom raider but then the engine check light/ traction control light and flashing dpf light came on. I checked for Codes with Freessm and P1469 was logged. I was unable to reset so i took the dpf differential sensor pipes off to get the % soot accum down from 180 to 48. I was then able clear p1469. The engine check light and traction control light are now off but the flashing dpf light is still on. I have fitted a clean dpf and refitted all sensors but still a flashing dpf light and no trouble codes. The soot % is 40 but cant seem to get a regen going. Any help would be appreciated, Thanks


    • Hi, most likely due to P1469 “DPF Limp Home Mode” the “dealer visit request/compulsory regeneration required” flag has been set since then, it’s one of the 4 conditions to trigger DPF light flashing. The flag gets saved into EEPROM, hence survives battery disconnect, by the way.
      Once the flag is set, either a compulsory regeneration must be performed (only allowed if soot is below 135%) or DPF replacement (+ special ECU DPF reset), both using dealership SSM-III/IV software.
      If you have RomRaider or other setup working where you are able to send & receive custom SSM2 commands, I can help to confirm and possibly fix your issue. Oil dilution reset won’t help here. Because of mentioned flag, it won’t perform active regenerations anymore – soot will be rising above 65 % – better not drive much!
      Contact me via email, please, for further details, include your ECU firmware version (AFAIK latest is from 2012-07, CID JZ2F441A, ROMID 6644D87607, CVN BBC8A374 E7B37BD0) and OBD interface(s) you’ve got (RomRaider/FreeSSM serial compatible, ELM etc.).


      • Kevin Gorman

        Hi Subdiesel,
        Thank you for taking the time to respond. Will i just post the answer to your questions about my car? I have rom raider and freessm. Im not a coder by any means but can follow instruction so if you are willing to go through what is required id be delighted. I will get the firmware info require.


      • Email is required for data file attachments etc.
        Would be ideal if you get ecuMem tool working from http://romraider.com/forum/viewtopic.php?f=32&t=8513.
        Have you got any ROMID yet – RomRaider and other tools should display something. Or do RomRaider Tools|Launch Test App… and send init command, it is in the response.


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