Been working on this one for a while, finally making my way here. I have a 1991 XJ40. I’m already aware of rain getting into the car, but I forgot the cover one night and a big rain hit. The day after, transmission started acting up, but only after warming up for a bit.
Felt like Limp mode. Transmission light didn’t come on neither did error codes. The Transmission light eventually did come on after battery drained out / was charged again.
Checked the TPS and checked the purple cube relay under the hood (I believe that’s the transmission relay).