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Any 5R110 gurus on here?


Red Skull Member
May 20, 2020
Member Number
Having a weird issue with a customers 06 F250 5.4 4wd 5R110 truck. ISS codes, even with a new oem sensor and the truck locks up the rear axle driving down the road. ISS is reading a few rpm below the crank rpm but never drops out. P0718 codes. Sometimes P0715. Halp!
Did you check the harness? End to end for continuity?

P0715 & P0717

Demon Dually
Joined Oct 27, 2009
5,140 Posts
#3 Oct 25, 2012
Take a look at your instrument cluster as well. Watch to see if your speedometer drops off to zero and the odometer goes blank. It is a common problem with the ford clusters due to poor solder connections on the PSOM board. You have two options if that is the case. Either replace the PSOM or have it repaired. I personally have taken mine out and resoldered the connections. There are two capacitors that then to come loose due to heat as well as the main chip on the board.
For poops and grins I would check both sensors for continuity too. It IS possible to get a bad part out of the box. I'd still lean towards a bad wire, inadvertent ground, or some other electrical gremlin.
I could email you the factory Pinpoint test if you want. Message me
I just pulled th transmission harness. It was burned on the right exhaust manifold. I am pretty sure the lockup was when the crossed wires energized random solenoids and put it in 2 gears at once.
It made for an exciting ride when it locked up the rear at 60 mph.