Yes I know it will temporarily clear the fault code but how do you comPletely clear all codes so I can get any new code readings.

 

Disconnect the battery for a few minutes (I use 30 minutes myself) and the codes will be gone completely there is nothing temporary about it. Any time you check codes after the battery disconnect only newly set codes will be there.

 

You will get 12 and 55 no matter what.

Code 12: The battery has been disconnected and the computer (ECU) has been reset

Code 55: End of fault code list

Also if you try to read the codes after clearing then recheck before starting you could see code 11: The engine has not cranked since the battery was disconnected