throttle positioning sensor

[c-los]

What is this? My service engine light came on and I did the ECU diagnostic and the code it came back with was 2135 (throttle positioning sensor). I was just curious to know what exactly that means before I take it in. I noticed a big decrease in power as soon as the light came on.

[DoggyDoor]

Since the G is a drive by wire, it seems like the throttle plate is out of position, or the motor that controls it is wearing out, making it less responsive. Probably pretty important, as you don't want the motor to quit with the plate closed, or worse, at WOT.