On a 1994 Lexus ES 300. Ive had the radiator replaced because they said the transmission is cooled by the radiator and it was time for a new one anyway, The speed sensor on the side of the transmission replaced. still not changing out of 3rd gear. They replaced the top speed sensor, the one that reads the revolutions and still the samel!! Last code that hit was the P0125 The coolant temp sensor. the computer has to read that the temperature is good before it will shift into overdrive or pass 3rd gear. I changed that. They told me if I changed it and if it didnt work to bring it back and they would clear the code and see what it does. I manually cleared the check engine light by taking off the negative battery cable off and pulling the ECU Fuse. I did turn the light off and when I started driving the tac wasnt reading but as soon as the tac popped back on, the O/D light started flashing at me again. Again, with the ECT button pushed in, it will change gears fine up to 3rd and wont shift further. With the ECT button on normal, it revs up in and out of gear and jumps all around the place. So both transmission sensors have been changed and now the coolant temp sensor has been changed. Those are the last three saving graces, Anyone else have an Idea?

 

Hello,

Is the CE light off right now?
Does the tachometer work? If not, can you see the RPM on your OBD2 scanner?
Did you check the sensors' wiring prior to the replacement?

It seems like your transmission has hard times figuring out its speed, hence where your troubles are coming from, and hence why O/D won't engage..

Hope this helps and best of luck!

 

Dude, that shop has no clue what they are doing. Find a transmission shop . Have them drop the pan and inspect the shift solenoids.

 

So yes, The two that I checked both had the proper voltage. The two that the shop replaced, Im not sure if they checked the wiring on them but they did say that the issues the scanner was telling them have been cleared and that the last one was the cool coolant temp sensor which is the one I replaced. They have the car again today, just waiting on them to give me a call back. Im thinking, the way I cleared the check engine light, isnt the correct way to clear the P0125 code and that they can correctly clear it and it should be reading its speed and all that. Thank you for your response!!

 

LOL it is a transmission shop.

 

Like find a different one, don't you see that they just replace parts at one's sweet random, it doesn't work like that!

 

Yea I see, got it, thanks!!!

 

I understand that they were fixing the things that their diagnostics found. its kind of retarded that during their diagnostics they came to find that the coolant temperature sensor was bad. Why didnt they just replace that like they replaced the revolution sensor LOL? They said they don't do work thats not transmission related!! thats why I looked it up and changed it myself!

 

That is what's called a bad service..

Also, speaking of P0125 - I also have that code, and it is not as simple as it seems.. At first, I thought that it is there because of bad thermostat, because the car was taking around 20+ minutes to fully warm up. But when I replaced it, the code didn't go away, so I started digging. The Service Manual for my 2000 Lexus ES300 (p.201) states that it could also be related to the bad A/F Sensor.. Don't have much time right now, so will test it later. For now, try following drive patterns to "set" the ECU and see if it will go away..

Hope this helps and best of luck!

 

A/F Sensor? Do u mean Reset the ECU? I tried that by removing the ECU fuse and then disconnecting the negative and positive cable!!!!! it worked for a but, the check engine light went out. the tac didn't work but as soon as it started working, the check engine light came back on!! so somethin is still goin on with it!!! preciate your advice and help!!

 

By "setting" the ECU or the sensor I mean following specific drive patterns, at which the ECU is "comfortable" to start testing sensors. Your Check Engine light will continue to drive you nuts until the ECU will make sure that new sensor is functional.

As an example, here is how to set A/F sensor:

About A/F sensor - no idea, I just stated what is written in Toyota Service Manual.. Still worth checking though.

Hope this helps and best of luck!

 

AAAHHHH I got it so even though the check engine light is on the ECU still has to learn the driving pattern before it will reset itself. Even thought P0125 code is cleared, its gonna pop back on anyway until the ECU learns the driving pattern and then it will allow overdrive once thats learned.

As for the shift solenoids inside the pan, They determined that there is overdrive, it is present. The car shifts gears perfectly, it just will not shift out of third and what is seemingly the problem where the computer isnt sensing what it needs to in order for it to allow the shift into overdrive or 4th and 5th gear.

 

You can go to a local parts store and ask them to scan your computer, they usually do it for free. If the ECU senses a decrease in engine's capabilities, or the "degradation" of the engine (misfires, knocking, etc.), it will not allow the O/D to engage. That is probably where you should be looking.

And also about your tachometer - as of right now, is it working or not. If not, can you pull up the RPM count on an OBD2 scanner?

Hope this helps and best of luck!

 

Ok I got it, The shop still has it, the rpm gauge works fine, it was just when I reset the ECU it didnt come back on right away. It works. as for the ECU, that's probably what is going on with it because it really had me thinking the transmission was shot but now that I know it's simply something going on that the ECU doesnt like, I can continue to replace damaged parts that may be upsetting the ECU.

 

Stop wasting your money replacing parts that arent going to fix your problem.. like I said, the transmission shop currently working with your car dont have a single clue with what they are doing. Find another one asap. All you need is a simple shift solenoid replacement and maybe a valve body rebuild. Just throwing parts at the thing isnt going to help.