Any resistance in the wiring?

 

I am having a similar issue, I just bought a 2012 Corolla, and it ran and drove home when I bought it (yesterday) but when I went to start it today it wouldn't start.

After some diagnosis I found that the throttle body valve is randomly spasming, and it won't respond to the pedal while it is doing that. When it isn't I can open and close it like it should with the pedal, but as soon as it starts to shudder it won't respond anymore. I am getting the codes P0121, P2121, P2138, P060D, and P060E, so basically all of the position sensor and performance error codes. I checked that it wasn't the pedal by unplugging it from its harness, and it still did what it was doing.

The reason I haven't tried replacing the throttle body yet is because I can't figure out why it is doing this without the engine on at all. The vehicle won't stay running due to the fluctuations in the valve, but all I need to do to make it start acting up is to turn the key to run, without starting the engine. It isn't the battery either, I replaced it today with hopes that it was just weak, but it didn't help. Any insight or ideas would be greatly appreciated!

 

I had

I am having a similar issue, I just bought a 2012 Corolla, and it ran and drove home when I bought it (yesterday) but when I went to start it today it wouldn't start.

After some diagnosis I found that the throttle body valve is randomly spasming, and it won't respond to the pedal while it is doing that. When it isn't I can open and close it like it should with the pedal, but as soon as it starts to shudder it won't respond anymore. I am getting the codes P0121, P2121, P2138, P060D, and P060E, so basically all of the position sensor and performance error codes. I checked that it wasn't the pedal by unplugging it from its harness, and it still did what it was doing.

The reason I haven't tried replacing the throttle body yet is because I can't figure out why it is doing this without the engine on at all. The vehicle won't stay running due to the fluctuations in the valve, but all I need to do to make it start acting up is to turn the key to run, without starting the engine. It isn't the battery either, I replaced it today with hopes that it was just weak, but it didn't help. Any insight or ideas would be greatly appreciated!

I had codes P0121 and P0123 along with some codes about the accelerator pedal. However, the diagnostic tool was seeing changes in voltage when the accelerator pedal was pressed so I ruled that out. I bought a used PCM on ebay and installed it but no difference. The +BM voltage is still reading 0 even though I can back probe those wires on the input of the PCM and get 12V. At that point I gave up and took it to the shop. Hopefully they can find something. I'll let you know.