Just had a 2003 Santa Fe given to me. It ran great for a couple of weeks, then it started bouncing between having power and no power...which was real fun on the interstate. It's throwing a P0122. I've tried 3 different sensors. I've checked grounds and replaced several sensors...crankshaft sensor wire insulation had rotted off, so I'm sure it was problematic. I have a launch OBD reader and in looking at the data stream, there are two throttle options. One shows throttle position and the other details what I assume is the voltage from the signal wire. The position line on the graph randomly goes to zero/closed then opens back up. When this happens the actual voltage does not change. The idle speed follows the indicator, not the voltage. For example, if I open the throttle to 3000 rpm, the position line will drop to closed and the engine speed will fall to about 1100 rpms. The signal wire voltage does not change. Once the position indicator jumps back to open it returns to a 3000 rpm idle. Bear in mind the physical throttle position has not changed. I've changed TPS, IAC valve, plugs, wires, coils, cam and crank shaft position sensors, and the evap canister. The only things on the list that I know needed to be replaced were the crank sensor and evap canister. Not sure where to go next. I'd rather not replace the computer without knowing if that will actually fix the issue. I'd appreciate any suggestions. I'm about to sell it for scrap.

 

I have a 2005 Santa Fe, so I can't add useful information, but in seeing the condition of some of the wiring in my engine compartment it seems to me that it would be time to replace the wiring harness. Which I wouldn't do because the problem could be the computer. And because other things are likely to be failing soon: replacing the timing belt and water pump was a $1600 job a couple years ago (in Oregon). Replacing the radiator was a do-it-myself job with assistance from my son, but he had a badly cut finger, so I did most of the work (I'm 75 now but I'm a computer nerd and barely qualify as a shade-tree mechanic.) My guess is you were given a money pit and there are plenty of other more useful projects at which to throw money and time. Like maybe a 2005 Mustang or like my 1990 Bronco II. There might be someone who has the same rig and wants to make one good rig out of the two. Just my humble opinion.