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PLEASE HELP! differential pressure sensor location?

Sean025

New Member
Joined
Jan 20, 2020
Messages
3
Location
Newcastle upon tyne
Car
Mercedes sprinter 2.1 - 311 (906) 07
Hi guys, new to the site and owning a sprinter too. Today travelling back from work MIL light came on, lost pull (not limp mode though). Got home and scanned it and came up with the 2078 (P1402) code, differential pressure sensor, plausibility error. I've got a new sensor on route but I had good going over where I'd expect to find it and I came up with nothing. Can anyone assist me on this please I'm really not familiar with these vehicles and I called it a day due to daylight I thought id seek some direction.

Its a 57 plate 2.1 CDI, 311 sprinter (906) eng code: 646.985 DPS code sprinter.png
 
Follow the exhaust down to the DPF, there are 3 tappings, 2 are flexible hoses the other is the temp sensor.

The 2 flexi hoses (fore and aft on the DPF) go to the diff pressure 'switch'.
They are measuring the difference in pressure on each side of the filter. Too high a differential and the filter is blocked.
 
went out shortly after seeing your post and checked and just managed a minute to update, its tucked away under the driver footwell below the chassis. near the shaft as pictured. cheers AMGeed
 
Last edited:
Follow the exhaust down to the DPF, there are 3 tappings, 2 are flexible hoses the other is the temp sensor.

The 2 flexi hoses (fore and aft on the DPF) go to the diff pressure 'switch'.
They are measuring the difference in pressure on each side of the filter. Too high a differential and the filter is blocked.

thanks m80, spotted the sensor by pics and an image of its appearance, never thought to chase it back as obvious as it sounds. sensor should be here tomorrow ill fit regardless. think ive rushed my assumption on the sensor ? I considered a choked DPF... but with the code implying sensor error and no limp mode I assumed correct temperature being detected.
 
The diiff sensor is a common fault, apparently. You may find you need to force a regen, but that's only if the system is happy that everything is correct. If not it may have inhibited a regen causing a DPF issue.
Personally I think the whole DPF system sucks and is just a poorly engineered problem waiting to take chunks out of your wallet.

I think it's worth familiarising with the various sensor readings while things are healthy, and at different stages of engine temp and regen cycles. That way it's possible to recognise when things aren't correct.

I use Torque (free Andoid app, the pro is cheap enough) via a BT transmitter (approx £4) into the OBD port.
The 2 exhaust temp's can be interesting to watch during a regen.
 
You need to get out more. lol.
I use torque too and see some weird readings. I have yet to spend enough time looking at it to be able to see the regen - the display is pretty small to be using while driving! I have no idea how frequent a regen is either. Weekly?, monthly?, depending on mileage, type of trips etc.
btw- I heard a common diff pressure sensor issue is broken/loose connections due to vibration/heat.
 

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