Hello all, I have a 2003 xj8 with 90k miles. I have the above engine code p0743 for torque converter clutch solenoid. When driving the car throws a gearbox fault message and limps, but when I turn the car off for a minute and restart it it goes away. If this is a bad solenoid, it it something you can replace or due to the non serviceable gearbox would the whole tranny need to go, or could it be something totally different causing it?
Thanks!

 

The solenoids are mounted into the valve body which is accessed by dropping the fluid pan from the bottom of the transmission.
Before doing that though get it on a lift and check the transmission for fluid leaks around the electrical connectors. The seals can fail and saturate the connectors.

 

Do you know why it only seems to act up when the car is first started, but goes away if I turn it off then back on once it warms up?