O/d Warning Light Blinking

[Harold]

Hi,After start up my " O/D" off light starts to blink and my vehicle will sometimes not change up to 4 th gear nor can I use the tiptronic controls on the wheel. The "M" also just flashes on and off. Then after sometime the vehicle will suddenly engage into 4th gear and all seems fine until I leave the vehicle for a while say over night and then again might have the same problem. Have tried reving the engine to the limiter whilst driving obviously when the engine is on temperature and that can sometimes engage 4th gear and cure the "fault".Arranged for Lexus to change the transmission oil and filters etc and also to check "fault codes" but does not appear to show anything.Has anyone else expereienced similar problems or suggest what the fault can be.The Lexus garage has been honest and said of course they could start to strip everything down to "find" the problem but of course it could be serious money.As the fault is intermittent, jsut wondering if anyobe can show any light on the matter for me. Thanks

[chips229]

Hi,

Sounds like a faulty sensor or poor bad connection,maybe a poor earth.

It might be worth checking all the electrical plugs that go to and from the auto gearbox.Unplug them and clean up the connections.

[Harold]

Hi,

Sounds like a faulty sensor or poor bad connection,maybe a poor earth.

It might be worth checking all the electrical plugs that go to and from the auto gearbox.Unplug them and clean up the connections.

Hi Chips,Thanks for your reply.Have checked workshop manual CD and it has 2 speed sensor coonectors,input turbine speed sensor connector and counter speed sensors, etc as well as a ground cable.

I guess this is what you mean and will certainly give it a try as it could be that simple.Must admit my wife thought it might just be a electrical fault but being a MCP, ignored her comments. If you are right and it fixes the problem it will cost me a lot of shopping. Cheers Harold

[Harold]

Hi Chips,

It is not the connectors as all cleaned up etc. I have noticed that if I take the engine up to approx 5 - 5500 rpm in 2nd when ATF is hot that it will suddenly engage the 4th gear and appears to be ok after that.I presume it has something to do with a sensor which measures engine speed.Any idea which one it could be ?.

According to the manual the sensors can be installed by removing Battery and air filter only so does not seem a major job. Have contacted Lexus and asked them to get prices on sensors as it has two and might replace both to be sure if not too costly.What do you think?

regards

Harold