I just got done buttoning up my car (2014 XKR) after doing some pretty substantial (for me) work on my car. I had a coolant leak that prompted me to replace a bunch of hoses, pipes, water pump. While the supercharger was off, I did an SC oil change, replaced the snout, and put a new isolation coupler in. Any gaskets that were removed were replaced with OEM gaskets.

Because I couldn't get to the engine coolant plug, I vacuum-filled the system, got the car up to temperature in the driveway, and then let it cool down before draining the radiator and repeating the process until the coolant I got out was the same color as the stuff I was putting in. I did this because I bought the car two years ago, didn't know what the state of the coolant was after almost 50k miles, and had added UV dye to my coolant to try to track down the source of my coolant leak. For each heat cycle I went through, I'd start the car, let it idle until the idle came down, then I'd give it some gas to rev it up to about 2000rpm until the coolant got up to over 200F. I'd take my foot off the gas, stop the car, and then go wait for it to cool down so I could go do this all over again.

Anyway... I got the car buttoned up. I pulled the battery cables, connected them, then let them hang for about 30 minutes. I reset the parking brake. I reset the windows. I reset the various engine computers by idling for 2 minutes, idling while standing on the brake while the car was in drive for 2 minutes, then going for a shake-down drive. I got less than a quarter mile away when the car sputtered and died.
ODB2 reader showed:
P2105-00 Throttle actuator control system - forced engine shutdown.
P2118-19 Throttle actuator control motor current range/performance.
P2119-00 Throttle actuator control throttle body range/performance

When I started the car back up, it said I was in degraded performance mode. I was barely able to "idle" back home. Throttle response was literally nonexistant.

I tried resetting everything, again. Same result. The electrical connector into the throttle body is firmly secured. I pulled it out but appear to have broken the little fastener tab in it, so I can't hear it click when I put it back in. I did a search on the forum and saw that this could be battery. The battery is less than 4 months old and was on a tender the entire time I was working on the car (with the battery disconnected). I don't suspect the battery. I didn't find anything else of value (to me, anyway) on this issue when searching. The three codes all point to the throttle actuator control motor, so I suspect this is something in the throttle body. Is there a way to identify what the heck is going on without tearing back into the car and replacing the throttle body? I hate firing the parts cannon at a car without knowing that it's going to actually fix the issue.

Is there anything else that I'm missing, here?

 

I would try a hard reset battery disconnect.

 

Since all your codes say THROTTLE, I'd say you missed a connection with the throttle body.

 

I did that, already. Twice, in fact. Unless that's different from disconnecting the battery leads, touching them together, then leaving the battery disconnected for a half hour. The radio was reset, the parking brake had to be reset. It's that what you're referring to?

 

On this model year, there's a single electrical connector on the driver's side of the throttle body (LH Drive). That's plugged in, but the little clip on the connector is broken. I have a new connector on the way. The only other things that can connect to the throttle body are coolant lines, and they're on the bottom of the unit. They're also connected, and the hoses aren't kinked.

Given that the clip on the electrical connector is broken, I'm going to give that a shot. It makes sense to me that there might be something wrong in that connector. It's the only cheap solution, so I'm willing to fire the parts cannon at this thing.

What's frustrating to me about this is that I was able to work the throttle for days while I was cycling the car to flush coolant. The moment I tried to drive it, the throttle stops behaving. I pulled and re-plugged the electrical connector on the throttle body, and didn't see anything change. The engine runs for about 2 minutes and then it starts throwing codes.

 

Possibly when it goes from ‘open loop’ to ‘closed loop’ operation is when it detects the problem.

 

A slight update... I pulled the harness from the ECU. All of the wires pass continuity and resistance checks. Nothing looks corroded. The bottom of the fuse panel looks nice and clean, too. All of the fuses passed continuity tests.

I've turned up nothing in searching the net for answers. I'm starting to wonder if it's time to get this towed so I can get answers. 😭

 

Another update!

I got a bug up my backside and wanted to see if I could SEE the throttle open/close. I pulled the intake Y pipe from the front of the throttle actuator and found.... a shop rag. It's pinned by the throttle plate. Is there a way to move that plate on my 2014 XKR so I don't have to start the engine and pray that I don't suck that thing into the car?

 

Last update, I hope. The throttle body is motor-actuated and spring loaded. You can press the top of the throttle plate in towards the engine to get it to move. I was able to get the whole rag out of the throttle body. I'm going to bolt everything up, erase some codes, and then try to get this beast back on the road. Thanks for coming along on this frustrating journey with me. I hope I don't have any more updates/questions.

 

Well THAT could have caused a disaster.

 

Good find with perseverance. All i can say about the rag is WOW. Disaster averted

 

You’re not a surgeon by any chance, are you?