Check engine lights

[Gatorstan]

I bought a filter today but I haven’t found out where’s it’s located on my 14 Discovery

 

[Rich W.]

usually the rear, bottom, center of the tank as part of the pump assembly. Check back in a few for pics.

 

[Rich W.]

This is a typical DEF pump assembly on a Freightliner chassis:

Top view

view from back of unit

The filter is behind the round cap. The pump should put out somewhere between 110 and 150 psi. My 2015 DEF went bad in 2020 and was putting out about 1 psi. So if your efforts so far don’t correct the situation, the next thing to check is pump pressure. Unfortunately there is no code to read for a bad pump; just a code for “Low DEF” of something similar, such as your SPN 4364 - insufficient NOX conversion. So it‘s the next logical thing to check and doesn't cost anything to test.

 

[Gatorstan]

Thanks Rich I’ll start looking for the pump

 

[Gatorstan]

I took my rv to a friend that has a professional laptop with a scanner and he did a regen and cleared the codes and driving back home the codes did not come back also is there a way that I could do a force regen without putting it on a scanner

 

[Rich W.]

There probably is - try looking for the “shorting plug“ described in this method:

https://www.ourmotorhome.net/2017/docs/DPF_Regen_instructions.pdf

However its important to understand that regens happen in the DPF and that piece of equipment is mounted after the SCR where your SPN code was generated. Forced regens are important, but most likely will not solve your problem. I would expect your MIL to re-activate after some driving and/or ignition cycles.

 

[Gatorstan]

I haven’t changed my def filter in my pump but am going to today is it easy to do in screw the cap and pull out the old one

 

[Gatorstan]

I. Changed my filter today and before I drove it I cleared the codes and drove it about 25 miles and no lights came back on and Rich I appreciate all the information and have you ever did force regen by using the shorter plug and is it fairly simple also the def filter was really dirty and when I first Ed cranked it back up the def tank and pump was making a noise that I’ve never heard but after couple of minutes it stopped before I drove it

 

[Rich W.]

Thats good so far and the dirty filter may have been the culprit (would like to see a pic) since it can certainly restrict flow to the doser reducing the effectiveness of the SCR, but you should probably put in a couple hundred miles of local driving to make sure the problem is resolved before setting out on a long trip. I hope thats all it was. The different sound from the DEF pump was likely the pump running dry while the system primed itself.

And no Ive never done a forced regen with the shorting plug because I can do it from my ipad with OTR, but I located the shorting plug under my dash and printed the instructions from that link in case I ever need to do it. With OTR diagnostics, I dont have to wait until the HEST lamp illuminates, so I can do forced (parked) regens whenever I want as a preventative measure as long as I have an internet connection.

Pic of my shorting plug, left side under dash next to the OBD port complete with “regen” label to avoid confusion:

 

[Gatorstan]