r/FordTrucks • u/Advanced-Treacle-259 • 4d ago
Q&A: Maintenance | Modification 1994.5 Powerstroke Diesel speedometer and odometer not working
Not sure if this is the right area or not but I am hoping to get some help. I have a 1994.5 F350 Powerstroke truck. Of course it’s a manual non 4x4 dually. Truck has 111k on it and now the speedometer just does wacky stuff like sitting at 0 until you get to 40 or so MPH before it just flips all over the place and now the odometer reads 111,645.9 and won’t move after I drove it for 5-6 miles yesterday. Any help would be appreciated, thanks!
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u/LankyJeep 4d ago
Your PSOM has gone bad, a rebuild costs 150 bucks, lucky you have a manual it doesn’t affect you as much, in an automatic it causes a limp mode hard shift condition, the psom is located in the dash cluster behind your Speedo, it runs your odometer and Speedo, if it blanks out that is a sure sign it’s failed
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u/LankyJeep 4d ago
I have 3 Speedo clusters specifically because I was chasing a PSOM issue and I’ve been slowly sending them out for rebuild over time
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u/Advanced-Treacle-259 4d ago
Where’s best place to send it and the odometer doesn’t blank out, it still shows the entire time, it just doesn’t register any miles to it. I want it fixed because it’s got low miles and I don’t want people to think that’s because it’s broken.
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u/LankyJeep 4d ago
I used Module Mechanics, there’s a ton of threads on forums about it, is your odometer going blank but lights remain on? Or is it just freezing and not logging miles? If it’s just freezing that’s your VSS sensor and it’s a 15-20 buck part
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u/Advanced-Treacle-259 3d ago
The mileage is lit up it’s just frozen where it’s at. The speedometer needle sits at zero until around 40 and after that it just flip flops back and forth all over the place.
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u/LankyJeep 3d ago
That’s your VSS then, it’s on your rear axle at the top of the pumpkin, takes about 5-10min to replace
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u/grassesbecut 4d ago
It sounds to me like you need a new vehicle speed sensor.