Ford F550 Doesnt indicate P in cluster

Michael Owner/Technician Montreal, Quebec Posted   Latest  
2015 Ford F-550 Super Duty 6.7L (99T) 6-spd
Cluster Does Not Indicate Park

Hey guys i have a truck in the shop from a fleet client that came in for a P not showing in the cluster and transmission in limp mode.

This fleet client has a garage and they previously replaced the Neutral switch because it was codding. they also replaced the internal transmission harness. i found a few things the wrench light on was coming on due to a faulty brake switch & wiring (I repaired a missing ground, replaced the pigtail and the sensor. So my limp mode issue seems to be solved.) The transmission is not coding but in trying to figure out my missing park issue i took the TCM connector & found 3 green pins inside 1 broken, replaced the module & harness because it had already been chopped up a hundred times. Basically if i look at my data in the TCM and PCM on my Trans range pid every gear (incl. park) indicates properly & the vehicle starts in park and neutral but it never indicates on my cluster.(When looking at cluster Data it tells me no gear selected when i put it in P) (Park only all other gears light up in orange and data is good) I feel like this might be something going on on the high speed can because my gears on my cluster are always lit up in white (even after power down) and when i turn the key on i intermittently get a wiper on off (ive seen this usually when i have comm. issues on these). i have 3 codes on my cluster:

U0121:00-8A- / U0159:00-0A / 

and in my trailer brake U2202-60

These are the only codes i get, all modules that i have on the vehicle pass the network test.

just wondering if anyone has ever seen this?

Caleb Diagnostician
Mishawaka, Indiana
Caleb Default

Hey Michael. I assume you access to wiring diagrams. But ill just post this one. Have one question. Can you turn on the indicators on the IPC with IDS just to be sure they are ok? I know you said that data says " No gear detected" when the vehicle is in "Park" but might be an easy test. Anyway on to what I believe is your issue. The IPC gets a hard wired input from a microswitch housed in…

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Scott Technician
Chico, California
Scott Default

Have had a few fords with this. The cluster gets the other selections from the range switch. But it only gets the park command from a small switch in the interlock, I would look at the interlock switch at the shift column to see if there is one on this model

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Michael Owner/Technician
Montreal, Quebec
Michael Default

I was starting to have a feeling that this might be the case but was only looking at my pcm and Tcm diagrams I’ll definitely check this tomorrow thanks guys!

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Michael Owner/Technician
Montreal, Quebec
Michael Resolution

Hey Guys, So you were both absolutely right. i replaced the shift interlock switch & it shows park now! Still have a bunch of issues with various electrical accessories due to a bad bcm but at least this is solved! Thanks !!

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