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95 F150 hard shifting and erratic speedo

  #1  
Old 06-22-2011, 05:34 PM
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95 F150 hard shifting and erratic speedo

When i took the truck for a drive, it was shifing funny. Floor it and it revs high and slowly picks up speed. It acts like it doesnt know what gear to be in. The speedo is also jumping around and will not tell me the speed i am traveling. The motor is the I6 with the E4OD behind it.

I ran the codes and got a 452 in the CM. This states
Computer detected an error in the VSS or PSOM signal during the last 80 warm-up cycles.

The guy said that he replaced the VSS in the dif. I do not know what or where the PSOM is or if it is the same as the VSS.

Could that be my whole problem here?
 
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Old 06-22-2011, 06:37 PM
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The PSOM is the speedometer itself. It reads the VSS (vehicle speed sensor) which is located on the top of the rear axle. As the speedometer(PSOM) reads the VSS it processes the VSS and resends the speed info to the ECU(engine control unit) which controls how the engine/transmission operates. Since the speedo it bouncing around I think you should check the VSS in the rear axle. Even if someone said they replaced it, there could be bad wireing connections or the sensor impropely installed.

If the VSS checks ok, you may have to check the tone ring inside the axle it may be dammaged. If that is Ok, then the PSOM could be the problem and best way to check it out is find one in a junkyard and swap it in.
 
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Old 06-22-2011, 08:48 PM
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Originally Posted by Eddiec1564
The PSOM is the speedometer itself. It reads the VSS (vehicle speed sensor) which is located on the top of the rear axle. As the speedometer(PSOM) reads the VSS it processes the VSS and resends the speed info to the ECU(engine control unit) which controls how the engine/transmission operates. Since the speedo it bouncing around I think you should check the VSS in the rear axle. Even if someone said they replaced it, there could be bad wireing connections or the sensor impropely installed.

If the VSS checks ok, you may have to check the tone ring inside the axle it may be dammaged. If that is Ok, then the PSOM could be the problem and best way to check it out is find one in a junkyard and swap it in.
Would one out of a 94 f250 work with this 95 f150?
 
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Old 06-23-2011, 07:06 PM
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The PSOM itself should be a direct swap. As for the whole cluster, I am not sure without relooking up the info again
 
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Old 06-23-2011, 10:46 PM
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My 96 F250 with 7.5 had jumpy speedometer needle, late shifting and extremely hard shift, died when shifting into reverse or drive...changed instrument cluster (Speedo, tach and all gauges) fixed everything.
 
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Old 06-24-2011, 08:47 AM
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The PSOM:


/
 
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Old 06-24-2011, 12:25 PM
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Can i just swap that from the 94 F250 to the 95 F150 from the back of the cluster, or is it easier to just swap clusters?
 
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Old 06-24-2011, 12:34 PM
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You have to take the speedometer head out and then the PSOM unplugs from the speedometer after you take the PSOM screws out. It comes out the front.
Swapping clusters is easier as you do not have to take the cluster apart.





/
 
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Old 06-24-2011, 02:54 PM
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How easy is the cluster to take out? I have till sunday to get this truck done. Let's hope it isnt too difficult.

Still need to swap gear boxes. Of course the 150 and the 250 use different pitman arms... These are a pain to get off!
 
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Old 06-24-2011, 03:46 PM
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It's not hard. I just did mine today had it out in about 20 mins. Pop off the two trim pieces under them are two torx screws then you can get the dash bezel out, there is also a couple clips that hold it in so don't just yank it then unplug tank selector switch so you can get the bezel out of the way. Then take off the panel underneath the wheel two screws and a few clips. I took the plastic from around the Colum off I'm not sure I had to but the cluster didn't seem to want to come out with it on. It's four screws on the under side then take out the ignition cylinder and the plastic will be out of the way. Then shook the little cable for the shift indicator. Then four screws on the cluster and you can pull it out enough to unplug the three plugs behind it and it will come out. Sounds like a lot ,but its really not like I said had mine out in 20minutes.
 
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Old 06-24-2011, 05:31 PM
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Meant to say unhook the cable not shook.
 
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Old 06-24-2011, 06:31 PM
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Well i swapped clusters and its still doing the same thing... Is there another VSS in the trans? parts store guy said there is two listings for this truck. Ill be checking the one out in the diff in the mean time
 
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Old 06-24-2011, 07:17 PM
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From what I've learned on this forum there is only one and its on the rear diff. My 94 only has the one on the diff.
 
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Old 06-24-2011, 07:19 PM
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Yes the 95 only has the one VSS on the rear end.
 
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Old 06-24-2011, 07:23 PM
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All so try unplugging the Speed Control Module as that can give that codes also along with hard shifting just like the VSS or PSOM. I see now you said the speedometer was jumping so the speed control module would not be it.
You might try unplugging the RABS Module also as it can give this code also.
Or just unplug them both and see what happens.
 

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