2012 Expy EL Limited - 5.4 - Wrench Light help

[1111ExpyEL1111]

155K trouble-free miles until yesterday. Wrench light came on all of a suddent. No noticeable change in engine performance. Was almost home and when I got home I shut it off and turned it back on...no problems.

Today, on my way back home from Menards, the wrench light goes on again, cruise control turns off. The speedometer stops working. Continued to run fine. Get into garage, front parking sensors inop. I got another message but I now forget what it was (thanks to a stroke a few years ago). No check engine light. I didn't notice yesterday if my speedo stopped working.

I've read several "wrench light" threads but there seems to be no definitive fix. I don't own a Forscan unit so it sounds like a trip to the Ford dealer will be scheduled? I am a DIY'er, but don't want to throw money at problems that might not get fixed.

Thoughts? And TIA!!!

 

[S20Workstation4]

See if your local car parts store can scan the codes, most of them do it for free...
Make sure you ask if they can look for any codes that are "stored" from previous events. They'll have to look for them in the scanner as they won't pop up as active faults.

The speedo dropping out sounds like an OSS issue, located in the TCM within the transmission.
A bad OSS will almost definitely throw a wrench, also a OSS code will show up within the computer as well.

 

[1111ExpyEL1111]

See if your local car parts store can scan the codes, most of them do it for free...
Make sure you ask if they can look for any codes that are "stored" from previous events. They'll have to look for them in the scanner as they won't pop up as active faults.

The speedo dropping out sounds like an OSS issue, located in the TCM within the transmission.
A bad OSS will almost definitely throw a wrench, also a OSS code will show up within the computer as well.

Is the OSS TCM actually inside the tranny? Just want to get myself mentally prepared for a hefty repair bill.

 

[S20Workstation4]

Yes, the OSS is inside the trans.
It's attached to the valve body. It's a doable job for DIY, can be messy though...
If no experience with mechanics, then I would take it to a shop.

 

[1111ExpyEL1111]

Heading to a tranny shop trust now.