Thinking I have a split in a rubber DPF pressure pipe I dismantled the sensor mount today and removed the rubber DPF pressure pipes;

 

One rubber pipe goes to a metal pipe, which exits from the top end of the DPF (part 24) 

 

Bit shocked to find that the other pipe was only about 8" long and is connected to nothing, it vents to atmosphere. I was expecting this to be connected to a second post PDF pipe which would show the differential pressure pre and post DPF.  This rubber pipe hasn't been cut, and has no marks indicating it's ever been attached to anything. 

 

7zap catalogue shows 1.6 and 2.0 CR engines having 2 pipes, one each end of the DPF (part 25) 

 

Photographs on a google search, and photos of 1.6tdi DPF's on eBay only seem to show DPF's with one pre-DPF metal pipe. 

 

How can the DPF sensor perform correctly comparing pre-DPF pressure to atmospheric pressure, surely it would indicate a blockage and constantly regen ? 

 

Car is a 2012 model, no fix applied.

 

 

 

 

Post DPF pressure should be close to atmospheric due to the open tailpipe further down. So penny-pinching means you see what you've found; just the pre- connection

Just to confirm Wino's response, my Grandson's Audi A3 1.6 TDI has only one pipe connected to the Differential Pressure Sensor, with the other connector open to the atmosphere.

I suppose that makes sense, I'm no mechanic so that wouldn't have occurred to me!

 

So, a figure of 46 hPa just before a regen, dropping to 15 hPa afterwards is reasonably accurate?