will bad tps affect tac?

[papadiesel]

1989 F250 7.3 4x4 E4OD trans in limp mode, tac quit, glowing OD light, does not shift correctly, can a bad TPS affect the tac? Tac has always worked. Went to start in 9 degree, warmed up, went out to drive, trans in limp mode, have to start in second manually to get going then 3rd works. Had to drive home at midnight that way. Where to start? Hot batteries, new cables last year pos and neg, 1G to 3G upgrade two years ago, good alt output, instrument panel, relit, no brakes or corrosion. This just suddenly happened with no warning. Suggestions where to start? Wires look good to tac sensor, but how to test sensor? Thanks

 

[Shadetreemechanic]

Bad tach sensor will send tranny into limp mode. TPS will not affect tach. Try removing tach sensor and cleaning. Sometimes that helps.

 

[snicklas]

O/D Off light dimly glowing all the time, is a power failure to the TECA. Check the TECA relay and fuses. If it were in true limp mode, the O/D Off light would be flashing.

 

[papadiesel]

thanks. I will check it for them

 

[papadiesel]

And yes you nailed exactly what is going on

 

[papadiesel]

huge props to you sir the relay had rusted inside because I had disconnected it from an up direction mount it was laying down water got in it probably from a car wash before everything froze around here popped in New relay with the electric grease immediately light went out tack activated back in shape again huge thanks again!!!

 

[snicklas]

You're welcome