I have a 1994 ES 300 with transmission issues. The overdrive light on the dash blinks on and off and does not shift itself into low gear. I can shift it manually. This problem comes and goes. I have read several posts about this same problem on other models and years and it seems to be the same problem. Can anyone help me out with this?

In my case, on a Toyota Camry that I used to own, it turned out to be a speed sensor wiring problem. However, my speedometer an odometer were not working either. So it was relatively easy to diagnose.

There should be a trouble code and probably a check engine light associated with that.

Phil

Is your check engine light on? Usually if the knock sensor goes bad the car goes into limp mode and can't shift into overdrive. IF your check engine light is on and the code is for a knock sensor it is almost guaranteed replacing knock sensor will fix the problem.

I've got knock sensor code on my 93 (3VZ motor) and I don't have any of these symptoms.

Thanks Phil. I plan to take it to an auto shop I found that has a code reader for a '94. They are really hard to find. the Lexus dealership wants $150 just to read the codes for me. I found a shop near my house that has one and will read the codes for $75. I will get it to him next week and see what the computer is saying.

Buy a code reader in the price range of 20-60$ and pull the codes yourself. There's no reason in paying $75 to someone else to do this for you.

Coincidently, The Toyota Camry that I had, that had the same symptom as your 94 Lexus was also a 94.

BTW, even though OBD-II became mandatory in North America starting 1996, I believe that your 94 ES300 is nonetheless OBD-II, not OBD-I.

My 94 Camry however was OBD-I, (Lexus was ahead of its time) so you should be able to retrieve, reset codes, and check engine lights yourself with any cheap OBD-II reader.

Phil

I thought 94 was first year of OBDII for ES300 . Most auto parts stores will plug in and tell you for free, like Autozone, Chucks O Reillys, etc..You can also do OBD I with no reader, by jumping the OBDI port under the hood, then observe code and compare it to the chart. quite easy. here is a link for OBDI :
https://www.clublexus.com/forums/es3...ght-codes.html

If true, that is absolutely disgusting. My next car will not be a Lexus.

i hear ya Larry but donmcc is talking about one dealer. And if that turns you away from Lexus, you may not be able to drive anything if the potential diagnostic fee scares you away. Pick your poison cuz Ford, Dodge, Chev, Honda, Nissan, BMW, etc ...ALL have dealers that would do the exact same thing.

Ford charged me $300 to tell me my head gasket was blown. there might be a dealer in a far away land that doesn't charge (but doubtful).

the thing is, you cannot use an easily accessible OBD-II reader, because it started being the standard in 96. That's a tough break.

so donmcc, what did you end up doing? is your 94 OBDII? pretty sure 94 was the 1mz engine (vs. my 93 with 3VZ), so Toyota may have planned ahead and made it OBDII compliant. i've heard they are.

The 94 ES300 has ODB-II. I have a 94 and it is most definitely ODB-II

nothing yet. I have been working out of town for the past week and a half. I will be going home tonight and use the info everyone has sent me. I will get a cheap obd2 reader if possible but if it is an obd1 I can read the codes thanks to a Lexus post. I will definitely pull the codes this week end and post them with the " fixes".

I had the same issue on my 93 and it could be a shift solenoid or it could be blockage in the transmission valve body or it could even be the Main ECU computer. They have been known to go out and cause that issue where it wont downshift. Start with reading the codes.