Strange PSOM issues
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5th Wheeling
Joined: Aug 2022
Posts: 36
Likes: 1
Strange PSOM issues
Having a seemingly strange issue with the PSOM in my truck (96 7.3, e4od). What is happening is that the VSS signal going to the PCM will occasionally drop out, leading to very harsh shifting and flashing TCIL light. I have forscan on my phone, so I am able to see the live data and have verified that it is the speed signal that is cutting out. My speedometer/odometer never have any issues, it's only the signal going to the PCM that seems to have issues.
Through observation, I have found that the issue seems to be temperature/humidity related somehow. Just to illustrate, yesterday it was a clear sunny day and I had no issues at all, but this morning it was pissing rain and cool, and I had 0 speed signal to the PCM until I started getting heat in the cab. Once things warmed up the VSS signal started popping in and out, and after several minutes it came in full and never gave me any issues. I've noticed this behaviour is really consistent, no VSS when cold, but signal returns once can warms up.
Had anyone else ever experienced this? Does anyone know of potential fix beyond just replacing the whole PSOM? Thanks.
Through observation, I have found that the issue seems to be temperature/humidity related somehow. Just to illustrate, yesterday it was a clear sunny day and I had no issues at all, but this morning it was pissing rain and cool, and I had 0 speed signal to the PCM until I started getting heat in the cab. Once things warmed up the VSS signal started popping in and out, and after several minutes it came in full and never gave me any issues. I've noticed this behaviour is really consistent, no VSS when cold, but signal returns once can warms up.
Had anyone else ever experienced this? Does anyone know of potential fix beyond just replacing the whole PSOM? Thanks.
Thread Starter
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5th Wheeling
Joined: Aug 2022
Posts: 36
Likes: 1
That was my thought as well. I've had the board out and inspected it as best I could with a high quality multimeter but I couldn't find or see anything telling. There's a local guy I've used before who does cluster repair, should I just ask him to replace the caps and check the solder joints regardless of if he can find anything?
Mountain Pass
Joined: Jan 2020
Posts: 210
Likes: 90
From: Troy, MT
That was my thought as well. I've had the board out and inspected it as best I could with a high quality multimeter but I couldn't find or see anything telling. There's a local guy I've used before who does cluster repair, should I just ask him to replace the caps and check the solder joints regardless of if he can find anything?
Do a search here for a recent thread about PSOM repairs. Goggle Ford PSOM repair kits.
There's Youtube video out there about this PSOM.
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