2012 F550 6.7 TCM Problem

[truckpullin_75]

Have a customer with a 2012 F550 4x4 with the 6.7 that is stuck at the Ford dealer. Truck is bone stock, with the exception of a PTO, and has less than 50k on the clock. This is all second hand from the driver and the tech at the dealer, but waht I've been told is that the TCM is failing to communicate with the ECM. When it fails, the truck goes into what sounds like limp mode only allowing it to run 50 mph or so, the gear indicator goes blank, and then after it is turned off it will not restart. It has been "fixed" (new TCM) at least three times now, only for him to get about 60 miles down the road and do it again. I just found out this morning that the shifter doesn't feel right when it happens but I don't see that changing by anything electronic, that part may be in the driver's imagination. Anybody have any ideas or ran into this before?

Part of the problem is the truck is leased and the leasing company won't let anybody other than Ford work on it, even for an oil change.

 

[Wildman]

Have a customer with a 2012 F550 4x4 with the 6.7 that is stuck at the Ford dealer. Truck is bone stock, with the exception of a PTO, and has less than 50k on the clock. This is all second hand from the driver and the tech at the dealer, but waht I've been told is that the TCM is failing to communicate with the ECM. When it fails, the truck goes into what sounds like limp mode only allowing it to run 50 mph or so, the gear indicator goes blank, and then after it is turned off it will not restart. It has been "fixed" (new TCM) at least three times now, only for him to get about 60 miles down the road and do it again. I just found out this morning that the shifter doesn't feel right when it happens but I don't see that changing by anything electronic, that part may be in the driver's imagination. Anybody have any ideas or ran into this before?

Part of the problem is the truck is leased and the leasing company won't let anybody other than Ford work on it, even for an oil change.

First thing is to make sure that nothing aftermarket has been added into the vehicles communication network. Aftermarket modules will cause multiple issues, including some modules reporting a loss of communication with other modules, and the symptoms described.

After 3 TCMs, we can be pretty sure that's NOT the problem. TCMs rarely fail on these trucks. Therefore, the problem is with the network circuits to the TCM, the TCM connector (poor pin fitment), or a loss of power or ground to the TCM. Power, Ground, and network circuits are the only thing that a module needs in order to communicate with other modules on the bus.

To figure out what is causing the problem, the issue will first have to be duplicated. Then, a network test with the IDS can be performed. Relying on continuous memory DTCs is not the proper method for diagnostics.

Once the concern is present, the TCM should fail the network test. Then, the tech can follow the diagnostics published in Section 418-00 of the Ford Workshop Manual to inspect the power, ground, and network circuits to the TCM in order determine the cause of the fault.

 

[truckpullin_75]

Thanks for the info, I relayed the information to the dealer's tech.

Found out today that at least once or twice they were able to reprogram the TCM and get it working again, but this is second-hand information from the driver. The tech did say that it passed the network test (so he says) and they are now thinking it may be a short or bad connection inside the transmission.

Guess I'll just have to wait and see what happens. Would be easier if the dealer wasn't over an hour away. I have tried to get the truck to a closer dealer that we have used in the past but the company doesn't want to take it anywhere else. Their money I suppose.