Toyota Repair: 2007 Toyota Corolla S check engine light

Question
My check engine light came on (55,000 miles on auto)The code is P0741and my garage changed the OE SL Solenoid in the transmission along with putting in synthetic fluid with BG transmission conditioner.As long as I drive short distances my light stays off,but each time I drive on Highway over 100miles and stop for half hour and then drive back on highway the light comes back on.If I reset right away and drive the light does not come on immediately until I repeat the above step.The shop said the solenoid is engaging every time now but was not before change.He keeps mentioning fluid pressure when solenoid is working is around 90% and toyota does not have a spec on what it should be.Also I have driven at least 2000miles since this happening and notice no problem or noise with transmission(automatic shifts normal)My repair shop is done with car,is there a solution to this and is there a problem with me continuing to drive this car? Thank you for any response to this ? Doug

Answer
I believe there is still a recall in effect for the engine control computer which can cause this problem, I'll have to look into it a little more, please provide the following:
VIN#
Part number from the ECM, it is located directly below the glove box, there is a label with some numbers, the number I need starts with 89661-then some letters and numbers.