Dpf code high oil level P252F

Dpf code high oil level P252F

Postby AndyMq on Thu Jan 20, 2022 7:09 pm

Hi guys my 2018 threw a code P252F which is high oil level. I followed a previous thread that help me clear it with a very nice local shop. But my question is why would if get thrown in the first place. The last service was 5k ago the engine was running great. So why would the DPF light set off with high oil level. While the oil was high I do not think it was from the dpf putting diesel into the sump as I was on a 300km trip. I service it myself and the oil level was not over filled. Iv been told it may be leaking somewhere one of the gaskets to it could be the injectors. Cheers
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Re: Dpf code high oil level P252F

Postby DibbyDibbyDJ on Fri Jan 21, 2022 5:17 am

P252f is always due to ECU overfuelling engine to get DPF to regen, and failing to regen. It is not using a sensor to check the oil level, but it is counting how much extra fuel is going into the engine and the likelyhood of that fuel going into the sump. leaking injectors WILL raise the oil level, but give you lots of black smoke, but WILL NOT throw P252f

possibility 1.. During covid, cars have not been used as much in general or go as far or as fast. Long journeys are good but average speed must be above 40 kmh minimum to allow regen to start and complete. This is about 10% of causes of this code.

possibility 2.. Faulty exhaust temperature sensor. Giving erratic readings, and if it goes open circuit during a Regen it will stop the regen straight away. It will likely give you another code. Used to be the main cause, but now probably 10%

possibility 3.. Unmetered air leaking into the engine or boost pressure leaking out. Normally the cold intercooler pipe splits causing the Mass air flow sensor to calculate (x) amount of air going in, but (y) amount is only actually getting in, hence overfuelling, high soot build up and DPF blocking up and oil level increasing.

This is the remainder of cases.
2024 Outlander

mitsubishi-forums.com
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Re: Dpf code high oil level P252F

Postby BlueTriton59 on Fri Apr 15, 2022 9:29 am

Dibby, what brand/model intercooler hoses would you recommend to replace the (seemingly problematic) factory hoses?

Where to buy them?

For a MR Triton 2019 MY.

Thanks!
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Re: Dpf code high oil level P252F

Postby DibbyDibbyDJ on Fri Apr 15, 2022 11:14 am

I only use and recommend genuine Mitsubishi parts. I wouldnt say they were problematic. Considering the amount of vehicles we see compared to hose sales it is less than 1%
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mitsubishi-forums.com
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Re: Dpf code high oil level P252F

Postby Zwagerman9 on Thu Jul 06, 2023 6:24 pm

Hi Dibby,

Do these sensors fail without a CEL?

High oil on dipstick. Has periods of increased exhaust smoke (fortnightly to monthly) and only for a short duration of 5 or so minutes, not sure if this is a failed DPF regeneration.

I can confirm my intercooler hoses are intact, as are my intercooler mount o rings.

Thanks!
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