07 yaris 4th gear not shift

[Benghazi]

check lights pops up in my 07 yaris , i scan it with obd it says code P0500 the wheels speed sensor and the speedometer works fine but the transmission speed sensor read zero speed , every time i clear the code car get 2nd gear hard until the check light pops up again and it work fine , at highway the trasmission won't shift to 4th gear then the car slow down at 120km/h to 100km/h .
does the sensor causes all that ?

[CTScott]

Yes. P0500 is the speed sensor on the transmission. It would make sense for it to be the cause of what you are seeing.

[trupial]

I'm having the same problem, the check engine light would turn on and off randomly.

i changed the speed sensor, but didnt fix the problem it kept doing it.
not sure what to do anymore.

[Benghazi]

i change the sensor it still not work, each time i clear the code P0500 it comes back again when i drive, the car wouldn't shift the 2nd gear until the check light illuminate and the car works normally until speed 120 kph, at this speed the car look like have a speed limiter i can't give it more speed something limit the speed, and i didn't feel that 4th gear is shifted.
one mechanic says that the problem is in the transmission and the other says it's in ECM but to change it you need to change ECM and immpolizer and may items.

any one have an idea for this problem ??

[B.B._07]

i change the sensor it still not work, each time i clear the code P0500 it comes back again when i drive, the car wouldn't shift the 2nd gear until the check light illuminate and the car works normally until speed 120 kph, at this speed the car look like have a speed limiter i can't give it more speed something limit the speed, and i didn't feel that 4th gear is shifted.
one mechanic says that the problem is in the transmission and the other says it's in ECM but to change it you need to change ECM and immpolizer and may items.

any one have an idea for this problem ??

The speed sensor should be a 3 wire design, with an input 12V, ground, and typically 5V max ouyput. So with a multi-meter or test light check the connector that you have 12V and ground. Corrosion at the connector is also a common thing but I doubt that's you're issue if you're in (sunny and snow free) Libya.