Does anyone have any experience with PSOM issues?
My truck was shifting hard and driving like it had tranny issue, took it get looked at and they pulled a P0500 code (I think). They cleared the code and the truck drove great for a day but then went back to its old ways. I changed the VSS and disconnected the batteries for awhile to try to clear the code. Drive the truck and it is still acting up.


No ABS light, No check engine light, no "OD Off" flashing.... just odd shifting and the speedo has a slight wave/bounce when I get in the 40mph and up range. When I use Cruse control it dose not drive smooth, like it is trying to dial in the speed.


Most people might not even notice the problems Im having but Im **** and know its not supposed to drive like this.


Any thoughts?

 

I'm guessing if it were the PSOM, the problem wouldn't have gone away initially with the new VSS.

Another possibility is something in the diff, either a contaminant on the tone ring, or icky diff fluid interfering with the signal to the VSS. If your diff lube is old anyway, a refresh might be in order; would provide a chance to inspect the tone ring while the cover is off.

Did you happen to see any metal on the magnet of the old VSS?

 

When mine was messing up it wouldn't do it till after about an hour of driving. Mine would act up under 30 mph, the needle would bounce and the odometer would flash and it would either hang in low gear or shift between 1st and 2nd rapidly.
I'd pull it into manual 2nd till I got back over 30.

 

Where did you get the vss? I went through 3 from ford before I got one that wanted to play nice with my truck

 

I got my VSS from an auto parts store but its a motorcraft VSS sensor.


Its really hard to tell where the loss of signal is coming from. I have read all kinds of crazy stores like the issue was caused by the overhead light, or the windshield wiper....


Im about to take it on a road tip this weekend and hope it plays nice.


I have this issue and an issue with the rpm's bounce at idle when the truck is warm, only about a 50-75 rpm bounce up and down and only when the truck is warm. It just caused the truck to idle odd and sake the truck a little more.

 

My cruise control doesn't work so I replaced the factory VSS with one from NAPA, but it did not fix the problem. After reading that some had issues with the VSS from NAPA, as well as the Motorcraft VSS, I purchased a Dorman VSS. The cruise still doesn't work, but the Dorman VSS did fix a brake/ABS issue I had been dealing with since I bought the truck, which tells me the original had failed, and the NAPA unit didn't work. They may all come from the same manufacturer for all I know, this is just my experience. As far as the cruise issue, it's the PSOM, and I also have a severe bounce issue in the speedomoter too. I will be removing the PSOM in the near future and sending it to (Cluster Fix | Instrument Cluster Repair) to be rebuilt ($175 plus shipping).

 

Good to know that they can be rebuilt. I really don't want to use one from another truck.


I replaced my VSS with a motorcraft one but the truck still acts the same. I have less symptoms then most since mine just shift oddly and has a slight needle bounce.

 

PSOMs are interchangeable among OBS trucks, too. The calibration will be different if it's from a junkyard truck with smaller (or bigger) tires, but it will at least work.

I've read that the newer Motorcraft VSSes are plastic and not as reliable; some folks are scavenging the older metal ones from older junkyard vehicles and stashing them.

 

a junkyard PSOM is going to have inaccurate mileage too.

 

^^^^ Clusterfix claims they can retain your odometer reading unless it's "unrepairable", but I wonder how often they're able to do so with a PSOM like ours, depending on what they have to do.

 

IDK, but the lady I talked to at Clusterfix said they don't alter the odometer at all. I'm suppose to pull the center gauge unit (speedometer) and send it to them "intacked". If needed, and at extra cost, they'll send you a shipping container for your PSOM.