I’ve noticed that my DPF will read really low when compared to my idash. The Ford will display something in the area of 20%, while the idash shows 70%.

The interesting twist? When the idash gets to 100%, a regen starts. I’ve never seen it get to 100 and not start. The Ford display is a crapshoot when it’ll start. Sometimes the Ford is still showing around 40%. It’s amazing how different they are.

I have no idea what the Ford is reading, but it’s hard to gauge when you are about to hit a regen cycle when it’s lying to you. Either way, just thought I’d pass this along in case anyone else was looking for a reason to get an idash.



DPF % is on left pod, center right position. In this case it’s 97%, and the dash shows 50%.

 

The iDash is probably set on trigger while the truck shows percentage. Sometimes mine will trigger when the percentage is 40-60% but the trigger shows a more accurate percentage when it will regen. On a quick regen, the trigger will drop into the 40s. If it runs a full regen, the trigger drops down to 10 or less.

 

You know what I do?
I don't worry about it!
On the 22 there is no option to view the DPF loading percentage, and I have no need of any idash or any other gauge to make me worry with it.
It's like a hypochondriac who goes around taking his pulse or something all the time and hyperventilating when he is sure something is wrong!

The pcm on my truck knows when the dpf needs a regen cycle.
The most I do is note the temporary loss of fuel economy when the cycle kicks in, and then am happy when the fuel economy returns, beyond that I care not.

 

What do you mean by DPF loading percentage?

On my 22 I can see the DPF %. I had to enable it with Forscan.

 

Yes the DPF regen trigger goes from 0 to 100%. It is not the soot load.

It (the trigger) is accurate. The trigger is at 100% and the pcm triggers the regen regardless of soot load based upon miles driven.

If the soot load were to get at 100% before the trigger then it will regen based upon soot load instead.

When you tow it may get the soot load down to zero but the trigger will still have it regen.

I think up to 2022 MY (at least on my 2021) you can use forscan and disable auto regen so as not to needlessly regen when the soot load is not calling for it.

To have it regen based upon the trigger for no reason other than miles driven is wasteful if you can stop it from happening.

Check out your DPFDIS for the average distance between the regens.

 

When I still had a DPF to worry about my truck did the same thing. Scan Gauge would not match Ford dash. But once a regen COMPLETED they would go back to matching again. It was odd.

 

I've seen these discussions for years but never realized the simple explanation of why the 2 are different. Triggered vs load % makes it clear. Thanks!

 

You are not interpreting what the idash is telling you correctly.

If you are talking about the one that reads 97 in your picture then that is where you are wrong, that is DPF regen %, not how much soot load is in the DPF. Basically that is the "countdown" clock to regen which on most trucks is right about 500 miles, so the truck will regen when it hits 100 whether the DPF is at 20% or 90% full. The only way the truck will regen earlier than 100 on that reading is if the DPF itself is actually full before that gets to 100.

This is why many people turn off auto regen and wait till the DPF is actually full because like you stated your OEM read out is saying 40% DPF full but the countdown it at 100 so it regens anyway. you are just wasting fuel, basically you can go twice the distance between regens if you turn off auto regen.

There is a different setting in the idash that will show how much is in the DPF but it reads in a different unit so it still wont line up with the OEM DPF screen, i cant remember the name of it without going out to the truck to look.

 

First off the iDash is not doing anything more accurate than the vehicle is doing. The iDash is nothing more than a telemetry display, telemetry created by the vehicle's computers. The PIDs that you select to display on an iDash are presumed to be something that you are interested in by the PID's description which does not fully describe what it is and how it is derived, that would be found in a telemetry manual, which I am sure that Ford would not be willing to share with you. The DPFRG that you are displaying is more than likely a calculation made by the vehicle as to when a regen should occur, how does the vehicle do that, look at the telemetry manual, which you can't see. The DPF% displayed on your dash is derived by the vehicle by monitoring the sensors on the DPF. How does it do that, the telemetry manual would have a detailed method, but here is my take with over 20 years of spacecraft and ground station telemetry experience. Read forward and aft pressure sensors, apply calibration curves to sensor data, subtract aft from forward, apply another calibration curve to get %, display value. I read on this forum that some tech stated that the displayed % is not a true indicator of % clogged, but the actual % that would be displayed if the DPF was full would be 300%, so the dash display probably is not a true indicator of how near to full the DPF really is, that info would be in Ford's manual that we can't see.

Do I worry about a "supposed' discrepancy, no, I drive my truck and give it the proper maintenance that it needs and I do not worry about regens.