Freightliner Cascadias with Predictive Cruise Control

Michael Ludwig

Well-Known Member
20
So, who is running Freightliner Cascadias with the Predictive Cruise Control option?
Have you had any trouble with them? Specifically, no GPS signals in the cab while the Predictive Cruise Control box (IPPC) is powered?

My situation: I have two of them. They are 2017 models with consecutive serial numbers. The first one has been an intermittent problem since it was new, but over the past year graduated to a persistent problem. Every time you turned on the key, you could not get GPS signals inside the cab. The second one started giving trouble a few months ago.
We initially took up the problem with our dealer partner, but they were pretty much clueless as w to what the problem could be. Subsequently it was bumped up to the Detroit regional service rep., and the Freightliner service rep. They too had no idea what the issue could be, and escalated the issue to Daimler's electrical engineers. They were stumped as well.

So, we fixed it ourselves. It turns out that the issue is the IPPC box located in the center of the cab header. There is an access panel up there you have to open, and once open you will see two boxes in there. One is black, and the other is silver. The black one is the Virtual Tech (VT) box. The silver one is the IPPC box.

The IPPC box has two connections on it, one for the antennae, and the other for the power/data bus. Unplug both connections and the problem of no GPS signals goes away.
 

JN1981

Member
2
I've got 3 2019 with predictive cruise and have not had that problem so far. But now I will know what to do if it comes up. Does the predictive cruise still work after unplugging (I'm assuming not) If not, does regular cruise work?
 

Michael Ludwig

Well-Known Member
20
You're correct. Predictive cruise does not work after unplugging the box. Regular old every day cruise control does still work.

The theory my shop is working on is that the problem is most likely the wiring harness between the IPPC and the main harness. It is likely somehow leaking into the cab structure and turning the cab into what is for all intents and purposes a Faraday Cage.

Frankly though, it is not worth the time and effort to tear the cab apart to find the problem.
 

bellcitytransport

Active Member
15
I had an issue for several months similar to this. We'd lose the truck's GPS location every time the driver would go out on a run, but get it back on occasion during the trip. The truck never had an issue while at the yard. The techs assumed it was the driver trying to hide himself, but I knew the driver wasn't that type. Short version after investigating and questioning the driver and some troubleshooting, it was a DASHCAM, When on, it would cause a conflict of some type and the GPS would stop working. We replaced the dashcam with another brand and the issue never occurred afterwards.
 
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