Help - ECU Legacy Boxer Diesel
 

Hi all
I'm new here but am desperate for help. I bought a Legacy Boxer Diesel 6 months ago. The DPF light came on. Basically in a nut shell, It's still in the garage and they have told me it's gone too far for a forced re-gen, the DPF sensor has been replaced, the DPF is clean and clear the pipes are clear. Soot > 135% – DPF Limp-Home Mode = DTC P1469 or P246C: DPF light flashing: https://subdiesel.files.wordpress.co...mall.gif?w=770 and MIL on: https://subdiesel.files.wordpress.co....png?w=51&h=35. but the car is driving perfectly. Apparently we need some software to tell the ECU to go back to factory limits due to pressure sensor failure. Otherwise I think it's a trip to Subaru who will replace whatever it is they need to replace and we're talking thousands of £.
Don't know where to look or what to do next....

It should be like other subaru, if you change any sensor, you need to perform a reset of the Ecu
and drive after in order (for the ecu) to make the new learnings.
You only need a diagnostic tool (to plug on the obd port on the car) to do this reset.
Maybe a procedure without laptop or diag tool is possible on this car, I don't know

Thank you Yann
Yes we need to trick the ECU into thinking a new DPF has been fitted which I am told can only be done with the software. They have tried the diagnostic tool but it won't let them re-set the ECU because it's coming up with the limp home mode so this needs to be over written.

You need to use Subaru select monitor to reset the oil dilution and tell the ecu you have fitted a new DPF then run a forced regeneration but at the soot accumulation value you have it will probably abort the regen and throw you out but keep trying and it should get there after a few attempts.
if that doesn't work it's either a new DPF or send it away to be cleaned.
Its also worth doing an injector pump and injector re learn afterwards.

Thank you so much SMithys STI. I think that's what's happening. They are being thrown out. They have cleaned DPF and checked air is going through pipes. The car runs lovely but all the dash lights still on. I will tell them to try a few more times.

I'm petty sure I remember him saying it's a snap on.

I'm sure garage used a snap on :(

Just make sure they have reset the oil dilution as an orange flashing DPF light means the oil dilution ratio is too high.

Ok I will make sure they have done that. As far as I know none of the lights have gone off. And now the soot value has gone up!!!! But the DPF is clean. But they have found an air leak they are going to investigate. I think it's in the region of the turbo. Hoping this may be something to do with it. Plan is to get the right diagnostic tool. Run car until she gets hot and readings come down then run the tool that will re-set it. If that makes sense. I am totally a non car understanding so this is pretty hard for me to keep up. Any input gratefully received though. I did find a guy who can take the DPF code out of the ECU but garage doesn't want to risk that.

If you have a leak in the pipework that goes to the DPS it will effect the readings to the ecu as will a large leak in the large pipework pre turbo.

Does that mean it could be a possibility as to what the problem is?

Quite possibly but if you study the live data on the diagnostics you should with a bit of time and experience be able to pinpoint the problem to a certain degree.

Ok, well thank you. I shall wait to see what the garage says.

Another thing that should be mentioned after all the messing about and it does'nt matter if it was changed last week it will need an oil change for safety's sake.

Through experience on subaru diesels the soot value always goes up before coming back down during a forced regeneration.
The intercooler hose on the N/S of the intercooler is very common to split but you would hear it leaking when on boost.

Ok I will mention that too. I'm dreading the bill!!!!!

I did start to hear a sort of hissing noise when I put my foot on the throttle. I'm just really really hoping this might be it. The car is driving fine apparently but it's just getting those lights off. But they are obviously on for a reason. I don't know whether a split hose would show on diagnostics would it?

If your hearing a hissing sound get them to check the underside of the intercooler hose on the passenger side they always spit there.
Sometimes it will log a fault relating to the airflow/map sensor other times no code.

Brilliant thanks

Just to keep you in the loop. It was an air leak in a pipe at the back of the engine. Once replaced and DPF cleaned and re-genned all lights went out. Thanks to all that gave advice.