What did I break? Throttle body cleaning woes

Well those are both throttle problems for sure one is showing the circuit is too high and so on so you're looking in the right place I had this happen to a 2013 persona on an engine swap I took my original throttle body from my original engine and put it on the engine putting in the car and everything worked as expected so I'm guessing the throttle body that came on the used engine was not to be and it wasn't so I used mine and all was well so maybe you'll go to a junkyard and snatch a throttle body slap it on there in your car will be running or you'll go to the dealer and pay some crazy amount for a new one either way.

 

The throttle position sensor is really two throttle position sensors, so the ECM gets two independent readings it can compare to rule out sensor problems.

To make the comparison even more careful, the two sensors aren't made to produce identical readings, but to produce different readings with a certain mathematical relationship. The VTA1 reading has a certain constant slope with respect to the throttle opening, and the VTA2 reading has a 1.11 volt higher intercept, a slightly steeper slope, and a knee at a certain point.

That makes sure the ECM can catch problems like a short between VTA1 and VTA2 that would make them look like the same reading. A simpleminded design would think that looked fine, but the Toyota ECM will know something's wrong because they aren't different in the right way.



Your P0121 means that the difference between VTA1 and VTA2 is going below 0.8V or above 1.6V sometimes, and your P0223 means VTA2 is going above 4.8V sometimes (while VTA1 is betweem 0.2 and 2.02 V).

The simplest thing to look for first would be wiring damage, pinched or nicked insulation between the sensor circuits, that kind of thing.

If you have a way of tracking the VTA1 and VTA2 voltages while moving the throttle open and closed, you might see just how they aren't following the graph above.

If you see the problem at the ECM terminals with the throttle body in the car, the wiring might be suspect. If you can reproduce the problem with the throttle body on a bench, the sensor itself might have taken damage somehow.

 

Blame SAE. Your tech just didn't know what's in this post, to wit:

The trouble code situation is very confusing. Codes P0120, P0121, P0122, P0123, P0220, P0222, P0223, and P2135 pertain to the throttle position sensor. Codes P2120, P2121, P2122, P2123, P2125, P2126, P2127, P2128, and P2138 pertain to the pedal position sensor.​

So P0121 and P0223 are definitely codes about the throttle body sensor and nothing to do with the pedal. What confused the tech is that the fortune cookies for all of those codes all start with "throttle / pedal position sensor ..." because SAE picked that wording (P0 and P2 codes are all SAE standardized) and that's the wording baked into code scanner tools, so you still have to look the code up in the car's actual repair manual to find out if it's about the throttle body or about the pedal.

Well, you've got a nice new pedal now, anyway.

 

Gen 3 tried to get me like that too but I knew it was the throttle body because I was changing an engine and the car was running before the engine change then the new engine going in with its throttle body torque plate and what have you would not do anything in the car I immediately unscrewed the throttle body and dropped mine from my blown up engine or blowing up engine right on in the car started immediately pretty similar with this guy's car the throttle body just gave up the ghost electrically in the middle of the road drop another one on and don't look at anything else.