I did change the little shift solenoid in the transmission of my 98 GMC cargo van. It was easy, with the additional benefits of new fluid and gasket. But I watched a youtube were the shift solenoid in the 98 RAV4 was a much bigger thing and down underneath the breather assembly somewhere. It's hard to tell where exactly the guy was pointing to. I thought someone might know. And I'm going by the code reader to know it's bad. :frownThe shift solenoids are in the transmission, you'd have to take the bottom pan off to get to the solenoids (which involves dripping transmission fluid everywhere). Probably more likely to be an ECM or wiring issue though, I'd test all that first. Do you have any actual transmission issues in driving? I'm not really familiar with the specifics of the '98 RAV4 though, you'd be better off asking on the RAV4.1 forum.