Toyota Repair: Check engine light, P1765 code, solenoid valve, resistance test

Question
We have a 2002 Sienna.  Check engine light came on and we had it diagnosed with the P1765 code coming up. We cleared it and the check engine light came back on.  We had the local shop
change the filter/fluid ...no chips in the fluid..no obvious wear. The local shop also measured the resistance on the solenoid and it was within specs. The code was cleared and the light came back on.

We took it to Toyota and they found "the shift solenoid not measuring the transmission accumulator pressure properly (erratic measurement)".

It's never missed a shift, or given us any trouble. We want the car ready and ok to travel but afraid to with check engine light on.  What can you recommend?
Thanks!

Answer
My best guess is that the shift solenoid valve should be replaced, I personally have not had this code before, the shift solenoid valve should be tested by applying voltage to it and observing the movement of the valve, resistance test is ok but not conclusive, the other possible causes are the wiring between the SLN valve and the ECM and finally the ECM itself.