tcc circuit is a GROUND circuit with 12V+ separate common to the transmission, check all your fuses and connections, a good manual will cover the wire color that pertains to TCC for your year of truck. At 53mph(49 on some trucks) with the fluid warm it should "ground"...you can bypass this to check it's function in case it's not grounding. Good thing it's a circuit code, that means hopefully just some patience and wire tracing and you will have overdrive and good (sort of) mileage again.

Connections- clean with contact cleaner, to both sides of connection, apply dielectric grease, reconnect.

Wires- look for abrasions, kinks and thin spots indicating breaks from being pulled on.

Fuses- Power center fuse under hood, and I'm not sure on the year but it may also have it's own relay.

I really reccomend a manual with wiring diagrams, you will need it.

 

Are there multiple connectors on the transmission that I might mix up when looking for the tcc circuit?

 

Only one eight pin connector. Drivers side, about halfway back on the trans. Plugs straight down into it's socket. You played with it when you replaced the solenoids.

 

Never replaced any solenoids, and I have TCC lockup, just no overdrive.

 

Oops. Getting my threads confused.

Could be as simple as a bad solenoid.... or bad connection. I would check wiring first, dive into the trans only if you don't find another cause.