I have a new engine, pro-built transmission, and a Vig 2600 TC. It all has about 300 miles on it. I just recently have taken it over 50 MPH, in the past 100 miles on the setup. It was staying revved high on the highway about 2400-2600 RPM’s. I did think much of it, because I haven’t driven the car in 2 years so I forgot how it drives, until yesterday when I went to my friends house who lives right off the highway and the TCC locked on the highway after leaving his house. It then all clicked in my head and made sense, that my TCC wasn’t locking all and that’s why my engine was staying at high RPM’s on the highway.

Today I did a lot of tests; here is my troubleshooting process and what I have found:
- Checked plug on transmission, It’s was firmly in place
- Check resistance of TCC solenoid, it is 33 Ohms
- Used scan tool and ECM is grounding ALDL pin F at proper speed
- Checked voltage at ALDL pin F, it is 12v when computer is not trying to lock TCC. (remains at 12v when the engine is hot or cold and TCC is not trying to be locked)
- Hooked up a switch between ALDL pin F and pin A, the TCC lock works perfectly until the engine and trans heats up then it will no longer lock manually or via the ECM.

What would cause the TCC to not lock when the transmission is up to operating temperature??

 

You might check the resistance or the solenoid when it is warmed up, AND the wiring itself. DON'T burn yourself...some electronics get flaky when old and subjected to heat. Also check the wires to the computer and wiggle them (just to make sure they aren't getting fryed under the hood.)

Tom