Please fill out the following to ask a question. MAKE: Buick MODEL: LeSabre YEAR:1990 MILES: 91,000 ENGINE:3.8 DESCRIBE ISSUE....Neighbors car (used to be mine several years ago) goes in and out of TCC lockup 50-60 mph. No codes. I disconnected TCC plug on this 4T60 (THM440-T4) Trans and problem is gone and now, of course, check engine lamp comes on and off. How do I know if this is the TCC solenoid, the switch on the brake pedal. or the ECM or ?