Disconnecting TCU

If I disconnect the TCU, will the transmission default to having the torque convertor lock up?
Thanks
BSD

I do not know the answer to your question but why do you want to disconnect the computer?? I have the snap-on MT2500 and am able to read the transmission computer. It gives me output shaft speed, what gear, and if it in lock up.

If you are trying to diagnose the transmission then buy the tool like I did off of ebay OR take it to a shop with the right tools.

SInce my torque convertor does not seem to be locking up, I want to eliminate it being a mechanical problem. If it locks up with the TCU unplugged then I would know it was electrical. Also, on a tight budget, I need to try to figure it out without spending a wad.
BSD

I also did not think my transmission went into lock up until I hooked up the snap-on scanner - MT2500. When my XJ shifts into 3rd or 4th it is in lock up. It comes out of lock out when you go down hill etc. That is the clunk you hear.

The only scan tools which will read a renix 4.0 are the snap-on or the dealer tool.

What you are wanting to determine requires the scan tool. You need to hook one up and go for a drive. Driving around with the tool hooked up you will learn what the torque converter lock and unlock feel like. Lock is very smooth, unlock is noisy.

TCU disconnected mode with the selector in D is 4th gear, no lockup.

As for reading lockup or not, I went cheap and temporarily wired the voltmeter between the lockup-solenoid output and ground pins on the TCU. Not sure what pins those are, don't have the FSM in front of me.

Thanks, BRTB. That is exactly what I was wondering. I guess I will spend tomorrow testing the TPS and TCU to see which is the culprit
BSD

no tcu = 1-3-4 shift pattern with no lockup

power to solenoid 3 = lockup