Transmission done for or throttle sensor ??

[duke808]

Transmission or throttle sensor? Code p0120

Hey all, 2000 runner with 110k. I was in Zion national park yesterday climbing a hill when my check engine light came on. Car would not shift down when pedal fully pressed to the floor. Was going up a slight incline, with pedal to floor, and car would not go past 35mph. Only way to speed up was throwing it into gear 2. Once we got to some flat road I pushed pedal 1/2 way down and felt a heavy THUNK. Was able to replicate that noise about 8 more times.

Turned around and headed back to Vegas to switch cars with a friend. Car drove fine on the way back. Autozone said code was throttle position sensor, though an auto shop said they think the trans is on its way out.

In addition to this, the car has had jerky shifts (definitely hard shifts) for a while now and often clunks when going into reverse and drive. Does anybody know if a sensor could cause these issues? I did have my trans fluid changed a few months back and shop said everything looked fine..

Thanks!

 

[duke808]

Nobody??

 

[jgue467]

Well a p0120 does say, "If this DTC is stored, the ECM shuts down the power for the throttle motor and the electromagnetic clutch, and the throttle valve is fully closed by the return spring. However, the opening angle of the throttle valve can be controlled by the accelerator pedal through the throttle cable."

So what you described in your climbing driving conditions could be attributed to the above. I'd say its a fair guess the TPS is suspect but it can be tested via the FSM. Have one of those? :cowboy: