Hey, l was driving my 2007 5.4 on the interstate on cruise control when all of a sudden I heard a pop and felt a sudden jerk and my truck then proceeded to go into limp mode followed by the check engine light. (Side motor: my ac turned off) I then started to hear a grinding noise from the front of the truck. I eventually got to Advance Auto Parts and they ran my codes, pulled up 27; camshaft, oxygen sensor were majority of them but ac pulley was also on there. Once I got home I started inspecting thinking limp mode may just trigger several codes. I looked at the ac pulley and it's not spinning while the truck is on but I can hand spin it.

Esssentially, does the ac work in limp mode and would a computer read a whole bunch of codes because my truck is in limp mode and lastly does anyone have an idea what could be wrong? I just bought this truck and I'm not ready for major repairs. 😔

 

When you say the a/c pulley isn't spinning, I think you may mean the clutch is disengaged. If the pulley weren't spinning, it would probably break the belt, or the belt would burn up running across the seized pulley. Like I said, I believe what you are seeing is the face of the clutch mechanism not spinning...not the pulley.
I'm not 100% sure, but loss of a/c could be triggered by the computer once the truck enters failsafe/limp mode as a means to keep engine temps down, and reduce parasitic power consumption as your truck limps along.
I hope I'm wrong, but it sounds like something failed in your timing system (tensioner, guide, phaser), and that triggered the limp mode. Failure of timinging components can lead to a laundry list of engine codes. Good luck.

 

Update: I disconnected the negative terminal from the battery to reset the computer and ran my scanner for codes. This time, to my relief, it only pulled up 7 codes:
P0010 Camshaft sensor
P0020 Camshaft sensor
P0135 Oxygen sensor
P0155 Oxygen sensor
P0443 Evaporative Emmision sensor
P0102 Mass Air Flow sensor

All the aforementioned codes belong to fuse #32 which was indeed blown. So I tried unplugging all the sensors and put a new fuse in and slowly plug the sensors in until the fuse tripped. However, I got all the sensors unplugged except the upper 02 sensor on the passenger side (any help on how to get that would be appreciated). I figured I could still put a fuse in to see if it was tripped, which it was.

Long story short, do you think that sensor is the culprit since it was the only sensor plugged in and the fuse still tripped??

 

So when you say Tripped, you mean blown right? I have never seen an O2 sensor blow a fuse, I would start checking the wiring harness to it, and around the actual fuse box to see if there are any shorted wires. Good thinking on disconnecting all then reconnecting one at a time to find the problem. Check the wires, then disconnect the O2 sensor and put a new fuse in, see if it blows this time, if not, go to each of the other sensors and plug in one at a time checking the fuse each time. If you get all the way to the O2 sensor and that blows the fuse again, then you know for sure and just leave it unplugged until you can trouble shoot some more. Im betting on a burnt wire somewhere on the harness. Good luck.

Tom