Shift fault, will not shift out of park (resolved)

[mparz00]

Posting this as I just received Lightning back from dealer after 3 weeks and they had another Lightning in the shop with the exact same issue, so not sure how widespread this may be...

Received the 'shift fault' error and could not shift out of park, manged to get into neutral once once while getting loaded on flatbed. Dealer flashed the GSM (gear shift module) and that corrected the problem for a day. Error came back, re-towed to dealer, and they told me that truck needed a new rear motor. Error did not go away after replacement. Dealer then found a 'corroded' wire in the wiring harness to the rear motor which controls the transmission lock function. The strange part is they said there was no damage/wear to the wiring harness, just one bad wire inside. They were able to clear the error after repairing the wire.

The rear motor may have been damaged during tow as dealer indicated that the unit was making terrible noises getting it into the shop and they found metal pieces in the gear oil...

Once they realized the root cause, they found a different wire in the same harness also corroded on the other Lightning. Shop foreman did a really good job of explaining all the steps they went through and indicated that Ford has a new version number for the rear motor wiring harness, which was backordered.

Seems like a manufacturing defect and not sure how many others may experience this. My XLT was delivered in September 2022.

Sponsored

 

[AZT9]

Bummed you had to go thru this issue but appreciate you sharing. It’s folks like you on these forums that help collect valuable information and archive it for all. !

 

[TaxmanHog]

Thanks for sharing, who knows how wide this issue might become.

 

[mparz00]

If anyone has a full parts schematic, can you pull a part number for this harness? Dealer said it was a few feet long and went from the rear motor to main wiring harness, so I take it there is a connector on each end.

Given that both trucks had the same problem on different wires, I may order a replacement cable to have on hand. Thanks

 

[TaxmanHog]

If anyone has a full parts schematic, can you pull a part number for this harness? Dealer said it was a few feet long and went from the rear motor to main wiring harness, so I take it there is a connector on each end.

Given that both trucks had the same problem on different wires, I may order a replacement cable to have on hand. Thanks

I might be able to find it, but the best bet is wait for them to finish the warranty work, the p/n will be listed in the work order, then order a backup if it's a simple PnP situation. Also the PN in my reference might be outdated.

 

[mparz00]

Thanks. They repaired the existing wire and do not plan to replace the harness.

 

[TaxmanHog]

 

[TaxmanHog]

Get under there and look for the repaired wire, it's a rats nest of cabling, hard to say which is the item you're in need of.

 

[TaxmanHog]

BTW, my reference document does not have the component part numbers, maybe the dealership parts department can help.

Sponsored