Dannypot

Focus C-MAX 2L TDCI Safe Mode

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Hi there,

I want a little help. I have a 2006 Focus C-MAX 2L TDCI that is stuck in safe mode.

I have EML on at present and the error message states "Particulate Matter(PM)trap differential pressure sensor circuit" and "Particulate Matter(PM)trap differential pressure sensor circuit range/performance".

Three questions:

1) From what I can find via google, this is telling me that there is a difference between input and output pressure through the DPF - possibly a blocked pipe or dirty sensor but might also be the DPF itself needs replacing/cleaning. Is this correct?

2) Does this mean that my DPF needs replacing or is it more likely to be a sensor fault?

3) The Safe mode appears to have become intermittent. After 4 days of owning the car, I started it this morning and got the full range of Revs out of it for the 1 mile journey to school but then for he 15 mile route to work, I was stuck with 2750-3000RPM Maximum - is this a good or a bad sign?


I put some DPF cleaner into the tank on Sunday when I topped up (100ml to half a tank of fuel) and have been running it 30 miles a day at around 50mph for 75% of the journey times -  I will repeat this at each fill up for the next few weeks to see if it clears it and each time I can get higher revs out of it, I will do so as I know that this can clear the DPF and it's pipes and sensors (more google-ing told me that) - the previous owner had it for around 4 months but was doing about 6-7 miles per day for work and no more than 10 on a day off for the whole time he owned the car so I have a feeling it is just a plugged pipe. Would others agree or could it be worse than it seems?

 

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Additional. Garage regenerated DPF and took it for a run andnapparently it ran fine. Fault re-occurred on journey home.

Next day, i took a 600yd journey to pick up something from a friend and had the safe mode limiter on and eml on. Set off from there and had full range of power with eml on for a 2 mile run to the tip. Left the tip and was stuck at safe mode limitation again. Rescanned for error codes and the dpf is back. It says same as it did before with repeating entries in the scan results. All saying almost identical things. 

Can someone PLEASE HELP ME?

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DPF shouldn't be trying to regenerate so quickly after a forced regen.  I would suggest the DPF is probably getting full of ash if it's original on a 2006 model tbh.

Are the pipes and pressure sensor easily accessible on the CMax?  If so, remove the pipes and check they are free of splits and totally clear (blow something through them).  Make sure the pressure sensor plug is clean and well connected, and that the inlet port isn't blocked with ash.  

If that's all good, have you got diags that show live data?  If so, the next step is to see what pressure the sensor is reading while driving.  

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hi there, i missed your original post or i would have tried helping sooner. first thing you need to check is the dpf pressure sensor pipes where they attatch to the dpf, welk known to detetioate and break up. after that the sensor can be faulty.
so check the pipes and let us know what you find.

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I have been through a lot eith this issue and eventually found what i believe to be the fault. Even when sensor is disconnected, the "return" wire for pressure sensor signals is showing 5v, the exact same voltage as the power supply wire for the plug. Ground wire has full continuity to negative on battery. I believe that the issue is wiring but have no idea how to investigate further as i am no mechanic or electrician (the results above came from simple multi-meter testing).

Any theories on a next step (dont have ramps or much by way of tools).

Dpf was regen'd by garage, sensor was replaced with a new one and fault is no longer intermittent, i havent seen full range of acceleration since before the sensor was replaced. 

Any and all suggestions are welcome. Lol

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All pipes verified as complete and not blocked.when dpf was cleaned and checked over by garage too.

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