Oldsmobile/Buick Repair: p0742 code on 1998 buick, torque converter clutch, powertrain control module pcm

Question
hi i have a p0742 code on my lesabre which i had scanned now that is a tourque converter clutch circuit stuck on. i do not know to much about this except it has to do with the tranny. the engine light went off and the car is running ok but any info. on this would be aprecciated. would you know if it is elect. or mechanical thanx

Answer
Hi
Here is description of DTC
The Torque Converter Clutch (TCC) release switch is part of the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.). The TFP Val. Position Sw. is mounted to the transmission valve body.
The TCC release switch is a normally-closed switch. The switch signals the Powertrain Control Module (PCM) that the TCC is released. Torque converter release fluid pressure acts on the switch contact, opening circuit 657/1804. When the voltage on the circuit is high, the PCM recognizes that the TCC is no longer engaged.
If the PCM detects that the TCC release switch is closed when the TCC is commanded OFF, then DTC P0742 sets. DTC P0742 is a type A DTC.
(Type A means it turns on the Service engine soon light after 1 test run and failure).
It Could be either mechanical, hydraulic or electrical.
It is a pretty straight forward diagnosis.
Only problem is there is a step that MAY require removal of the transmission.
I would take it to a good transmission shop.
Let them run the diagnosis and eliminate the electrical.
I may be the TCC Solonoid. It may be the internal wiring harness.
I hope this helps.
Follow back post, if needed.
Good Luck
Pawl