Overdrive malfunction

My '99 RX-300 has a 3 speed auto transmission plus overdrive. When the car is cold all functions properly, but when the car is fully warmed up, more often than not, the overdrive function stops operating. If the car is at speed and in overdrive, it’ll remain in overdrive. However, if I stop at a light or otherwise significantly slow down (once the car is fully warmed up), it usually won’t shift from third into overdrive when I get going again (although on rare occassion it will).

A local garage mechanic and the local Toyota dealer both said they do not have the requisite diagnostic equipment for the codes that come up, and that I need to go to the Lexus dealer (unfortunately, I live in Juneau, AK, where there isn’t a Lexus dealer, and have no way to get to one).

Also, the “check engine” light is always on. Mechanics can determine no cause, and reset it, but it comes back on almost immediately. Finally, for what it’s worth, the cruise control indicator light functions intermitently/infrequently.

This one is easy and I’m not a mechanic.
This is a bad VSS (Speed sensor).

Might you elaborate a bit?
Why does it fail to function only after the car warms up?
Do you know what it might cost to check it out and/or replace it?

What codes are coming up??


I’ve had a bit on my plate since your reply, so here’s hoping you’re still around.
All I have is what the Toyota mechanic wrote on the service invoice:
“Scan tool tested (check engine light is on). Found default codes for knock sensor and fuel system lean codes. Was unable to scan system, found transmission faults. Recommend vehicle be taken to Lexus dealer.”

No one here will really be able to say much without knowing what all of the codes actually were. See what you can do. Many auto parts stores will scan fore free - but all the transmission codes might not come up w/out more sophisticated scanners. There must be a transmission shop in town - take it there (preferable a local, independent - avoid the corporate chain shops).

Is your road system in Juneau extensive to need overdrive?

Five miles of paved road and the only Lexus in town. The ferry comes up twice a week, right?

Maybe not this week…

The transmission shop suggestion makes sense…duh…although you’d think a Toyota dealer would be able to deal with it too…

They never saw a Lexus. They make their living installing clutches in 4WD Toyota trucks…