07 F-150 trans fault

[mosseater]

Truck in sig picture, 5.4 liter, 4spd, 4:10 rear. I know I'm towing at max CGWR of 15,300 or better, but this "trans fault" has been coming on with more regularity in the last two years. This weekend while traversing 7 Mountains on Rt. 322 here in PA, it started kicking the engine fan on right at the bottom of the hill, and shortly thereafter, the "trans fault" came up on the screen.

I detect no discernable change in performance when this happens. Once, two years ago, I was able to pull over within a 1/4 mile and shoot the trans pan with my IR thermometer and it was well within temp limits at around 250. I'm going to get it checked, but I'm wondering if this might be a sensor somewhere screwing up the computer parameters and sending a false code. The fluid looks and smells brand new (changed and flushed by dealership less than 20K miles ago) and there is no slippage. Not sure what to think. The engine temp needle never goes above 1/2 way up, even in the extreme summer heat and towing. I suppose once a fault is triggered, it stays in the computer until cleared? Would that mean they'd be able to pinpoint the issue with the reader? Thanks for any input.

[ggardne2]

250 fahrenheit at the pan is quite hot for a 4R70W transmission. I do not recall the exact set-point of the thermal bypass valve for the transmission, but for this vintage you should be running at 190F or less under normal operation. What is the build configuration of your truck, does it have max trailer tow with an oil to air aux cooler on the transmission?

It would be interesting to monitor sump temperature when you are towing. It also maybe worthwhile to scan for codes, I believe the P0218 code will store if it is set.

[mosseater]

OH, great! Not too convenient to reroute my camping trip to the nearest Ford dealer and let it idle while they find time to help.

On a brighter note, I found several references to the same fault display and one guy who had his fixed. Turned out to be a temp sensor in the pan. Unfortunately, they dropped my pan and changed the filter when they did the last trans service. Hate to go back in just for a sensor. If I can find out which one and where, I might give it a go myself. After that spark plug fiasco, this should be a breeze.

[Fast_Mopar]

mosseater wrote:
I suppose once a fault is triggered, it stays in the computer until cleared? Would that mean they'd be able to pinpoint the issue with the reader?

For regular check engine light codes, yes, but not necessarily true for transmission codes. My 2004 Ford Freestar van intermittently flashes the transmission fault light, and there is no stored code. Two different Ford dealers told me I need to bring it in when it is flashing and not wait until the next startup when it clears because the transmission codes are not stored. That is what the dealers both told me.

[ScottG]

Maybe a scan tool would reveal a code. You may even be able to get the boys at Orielly's to pull it for you.