Let me start off by saying I am definitely not a mechanic. I have a 94 Toyota Aristo/GS300. I bought this Japanese spec car here in the UK. The summer after I bought it I noticed that it would not go in reverse some times. I took it and had the transmission rebuilt. It seemed to work fine. I had no problems until the weather warmed up again. That is when I started to notice that it only happend when it is warm outside. I took it back to the trans shop and they worked on it again as it was under their warranty. They could not get it to go in reverse when it got warm outside. They took it to another garage who told them they think it is the ECU. I have no proof that is the problem. Now that it has been nice out the past couple of weeks it has started again. Has anyone heard of this problem or have any idea what it could be. I have an appointment with another garage this Monday. They said they don't believe it could be the ECU from what I have told them.
Any help would be appreciated.
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Lexus Owners Club > Lexus Models > Lexus GS 300 / Lexus GS 250 / Lexus GS 430 / Lexus 450h / Lexus GS 460 Club > Engine & Transmission
Hi and welcome to the club.
Sorry im not ble to help this is the 1st I have heard of this sort of problem... maybe you can try searching the forum r someone with better knowledge might come along and explain ( sorry new to the GS myself )
Sorry im not ble to help this is the 1st I have heard of this sort of problem... maybe you can try searching the forum r someone with better knowledge might come along and explain ( sorry new to the GS myself )
Cant see it being a problem with the box itself as this would reach the same temp in the summer or winter .
Welcome to LOC 
Have to admit this is a new one on me, not seen that problem before, might be worth you asking the guys over on the MKIV Supra club forums as you've pretty much got the same drivetrain and engine, think the ECU is similar too, maybe they will have some ideas of what could be the problem?
Have to admit this is a new one on me, not seen that problem before, might be worth you asking the guys over on the MKIV Supra club forums as you've pretty much got the same drivetrain and engine, think the ECU is similar too, maybe they will have some ideas of what could be the problem?
I had a simaler problem with a mx6 and it turned out to be a sticky solaniod ,not sure wether the lexus runs on the same system though .
I would agree with Mudzs here, and say it seems more like something sticking rather the ECU not controlling something.
If the ECU couldnt get it to go in reverse it would do that in all weathers as its just electrical.
Something sticking on the other hand would suggest its more mechanical, and mechanical things can very rarely be affected by the heat/cold.
Do this happen when you first start the car or only when the gerabox warms up? Or does it cure itself when the gearbox warms up?
If the ECU couldnt get it to go in reverse it would do that in all weathers as its just electrical.
Something sticking on the other hand would suggest its more mechanical, and mechanical things can very rarely be affected by the heat/cold.
Do this happen when you first start the car or only when the gerabox warms up? Or does it cure itself when the gearbox warms up?
[quote name='W4SIM' post='422978' date='Mar 18 2007, 11:24 AM']I would agree with Mudzs here, and say it seems more like something sticking rather the ECU not controlling something.
If the ECU couldnt get it to go in reverse it would do that in all weathers as its just electrical.
Something sticking on the other hand would suggest its more mechanical, and mechanical things can very rarely be affected by the heat/cold.
Do this happen when you first start the car or only when the gerabox warms up? Or does it cure itself when the gearbox warms up?[/quote]
This generally happens when the weather is warm outside and the car is cold. Sometimes once the car has been driven for a ways it will have reverse even if it did not when it was started.
If the ECU couldnt get it to go in reverse it would do that in all weathers as its just electrical.
Something sticking on the other hand would suggest its more mechanical, and mechanical things can very rarely be affected by the heat/cold.
Do this happen when you first start the car or only when the gerabox warms up? Or does it cure itself when the gearbox warms up?[/quote]
This generally happens when the weather is warm outside and the car is cold. Sometimes once the car has been driven for a ways it will have reverse even if it did not when it was started.
[quote name='ibgolfing' post='423136' date='Mar 18 2007, 07:32 PM']This generally happens when the weather is warm outside and the car is cold. Sometimes once the car has been driven for a ways it will have reverse even if it did not when it was started.[/quote]
Seems like what ever is sticking is managing to "un-stick" itself. This could be due to the raised temprature in your gearbox or the movement of fluid.
Point is though, what on earth in there could be sticking?
Seems like what ever is sticking is managing to "un-stick" itself. This could be due to the raised temprature in your gearbox or the movement of fluid.
Point is though, what on earth in there could be sticking?
[quote name='W4SIM' post='423282' date='Mar 19 2007, 08:45 AM'][quote name='ibgolfing' post='423136' date='Mar 18 2007, 07:32 PM']
This generally happens when the weather is warm outside and the car is cold. Sometimes once the car has been driven for a ways it will have reverse even if it did not when it was started.[/quote]
Seems like what ever is sticking is managing to "un-stick" itself. This could be due to the raised temprature in your gearbox or the movement of fluid.
Point is though, what on earth in there could be sticking?
[/quote]
Thanks for the inputs. I took it to a garage today and they hooked it up to a couple of different diagnostic machines and neither machine would even read my car. It sounds like my real problem is that the car is Japanese specs. No one is sure how to work on it.
This generally happens when the weather is warm outside and the car is cold. Sometimes once the car has been driven for a ways it will have reverse even if it did not when it was started.[/quote]
Seems like what ever is sticking is managing to "un-stick" itself. This could be due to the raised temprature in your gearbox or the movement of fluid.
Point is though, what on earth in there could be sticking?
[/quote]
Thanks for the inputs. I took it to a garage today and they hooked it up to a couple of different diagnostic machines and neither machine would even read my car. It sounds like my real problem is that the car is Japanese specs. No one is sure how to work on it.
Each part of the gear changes has a solanoid, the solanoid's are controlled by the ECT part of the ECU (I believe), the connectors on these can get very brittle over a period of time.
During my G/B rebuild, I had most of the connector replaced due to this problem, never had the reverse problems but did have the first gear shudder.
Hope this points you in the right direction in solving the issue
BR
Paul
During my G/B rebuild, I had most of the connector replaced due to this problem, never had the reverse problems but did have the first gear shudder.
Hope this points you in the right direction in solving the issue
BR
Paul
If the car has solanoids like paul says then i would almost certainly say that is your problem,i had to have a whole unit replaced as they could not replace single solanoid.and mine was affected by heat .
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