2000 I30 Transmission shift sensor or overdrive sensor

[ljensen]

During hot days(90 degrees and up) my I30 will not shift into overdrive when on the highway, it stays at 3000 - 4000 rpm for speeds from 60-70.

When I click off overdrive (just to try and get a reaction from the transmission) nothing happens, as if the O/D is already off...

This doesn't happen all the time, it's only done this 4 times since May. Has anyone else had experience with this?Thank you,LJ

[maxhopper]

It sounds like something with your overdrive control switch. The bad thing is that with the problem being intermittent, it's nearly impossible to diagnose.

To test, you can check the voltage on the transmission control module between terminal 22 and ground. Make sure the ignition is on, but that the car is not running. With the OD switch on, you should have approximately 12 volts. With the OD switch off, you should get 1 volt or less.

Here's the terminal layout of the TCM.

[ljensen]

Thank you I will check that first. The transmission temp seem unusuallly high under normal diriving conditions and this problem only occurs during high outside temp. I'll also check transimission fluid flow to radiator input and out. Any other recommendations appreciated.L Jensen

[pcrosby777]

My car is doing the same thing. Did you ever figure out what the issue was with yours?

Thanks!

[Infinitimm]

My car is doing the same thing, no idea what it is, Transmission control module maybe, it all started after i replaced the speed sensor so i think that set it off. I found that when my car isn't shifting into overdrive that shutting the car off, then starting it back up seems to help, but i would like to know what's causing it so I can get it fixed.