Won't Shift Into Od (well, Not Usually)

[family_man]

Anyone seen this before? Everything runs fine, just won't drop into OD (just like if O/D OFF button was pressed). This just started last week. Sometimes restarting the engine fixes it. I don't think this is related, but I've had the check engine light on for a while before this happened...code P0171 (running lean...but the engine seems to run fine...I went ahead and cleaned the MAF sensor). Thanks!

[SKperformance]

you might be running so lean it is causing you to press more on the gas pedal to compensate ,thus causing the ecu to not engage the shift solenoid for t/c lock up

[wwest]

The transmission fluid temperature sensor is inop. The RX will not shift into overdrive until the fluid temperature has risen to some reasonably high level.

[dieseltruck1]

The transmission fluid temperature sensor is inop. The RX will not shift into overdrive until the fluid temperature has risen to some reasonably high level.

I have the exact same problem as you family man. Goes into overdrive about 40% of the time. Same lean OBD II code. I was wondering if I need to change out O2 sensor(s) or check injectors but am holding off thinking there may be a simpler (and less expensive) explanation. The temp sensor idea may be a good one. If you solve your problem, let me know how. I'll let you know if I figure it out.

[ljl]

I had this same problem. We bought our 2000 RX used and shortly after SEL came on I think same lean code. After several resets at repair shop O2 sensor went bad and replaced it. Soon after SEL came back on but it ran OK so I didn't get around to having it looked at. Several months passed and then things started acting up, sommetimes loss of power,transmission hunting for a gear on acceleration and not always shifting to OD. Shutting off engine seemed to fix it for awhile. Took it to Lexus , they replaced the MAF sensor which fixed the loss of power and gear searching but not the OD problem. They talked about the fluid temp sensor but it checked out OK. I had it back to them three times and finally had a mechanic go with me for a drive where he witnessed the problem. They tried clearing the memory,consulted lexus tech assistance and finally at techs suggestion replaced the tranny. The OD problem was still there!!! Finally after 2 weeks they found the knock sensor was faulty and replaced it. PROBLEM FIXED!!!! I don't know how much the sensor costs, they were so embarrassed they warrantied the sensor,tranny labor and threw in some other stuff as well.

[SKperformance]

i would be embaressed also if i told someone to change there tranny for nothing

your engine does build up carbon rather easy as per its emmision requirements which cause carbon and alot of know if not cleaned as part of its regualr maintance