So... my Subaru died and it was time to replace it before it left me stranded deep in the boonies (where I go on a regular basis). I decided on an older Rav4 for a variety of reasons. Having not owned one before, I spent a few hours looking into known issues with the vehicle and how to spot those things in addition to the regular things to inspect when buying a car. I found one that I liked, it had a clean bill of health in every way I could reasonably inspect, it was a good price and I pulled the trigger. 2001 with 148k on the clock: perfect for my needs.
About 20 miles and 7 hours after buying it, the transmission started behaving erratically. Having done the due diligence research, I very quickly realized that it had the known issue of ECU failure leading to transmission performance issues (specific solder points fail leading to circuits behaving improperly). So, I gingerly drove the last 1.5 miles home and parked it. And swore a bit. A small number of the vehicles have to be driven for over half an hour to exhibit symptoms according to the Toyota TSB, which is why it drove like a champ during the test drive. Grrr.
Here's the DIY part: the prevalence of the issue means that a whole cottage industry has sprung up with people who know exactly the solder points on the ECU need touching up to resolve the issue, and who work on an exchange program. So, I ordered one of these units for $135. It arrived a few days later and the installation took about 25 minutes. This solved the problem and I sent my old ECU in for the core charge refund. Buying a new OEM ECU would have been over $1000 and the Rav4 forums are full of people who had quotes over $4000 to fix it, many of whom were told they needed a new tranny... which did not solve the problem because that wasn't the problem (unless you drive it that way for a while).
I expect the seller on the car lot knew of the issue and was dishonest (it is possible they didn't know, but unlikely). But, I got a good deal even including my repair cost, and relative to the private party options. I can't imagine the frustration this would have caused if I hadn't already known the issue and how easy it was to fix when it happened so soon after buying the vehicle.
