I ran a diagnostic on my 1996 chevy silverado because my speedometer and rpm gauge quit working and transmission was acting up. the code that i got was P1860 TCC PWM Selenoid Circuit and P1864 TCC Enable Solenoid Circuit. I usually do all my work myself and this has me stumped can anyone help or offer some advice. I think it has to do with my transmission if any one has had a similiar problem or know what this could be,, please help!!

 

TCC is torque converter clutch and i think PWM is for pulse width modulator, other than that i would have to check identifix

 

Lots of people have trouble with transmission and Speedometer at the same time and it is there Vehicle speed sensor but I do not think it would throw these codes.

 

Mine on my 1993 was doing the same thing right until the tranny stopped working altogether, the pump broke, needless to say, a full rebuild had to be done.

 

I believe this year truck is during the period when GM had problems with the ignition switch dropping power to the transmission. You can either get the electrical diagram and check powers to the trans or you can try to replace it to see what happens. I do not like just putting parts on with out testing but the switch is cheap enough that it is not to bad. Make sure you do the electrical part of the switch, some people assume that this is the lock cylinder but it is not.

 

I installed a entire wiring harness on my tranny which has solenoids and all but didnt make a difference, it needed to be broken down and checked anyway because of the mileage.