Hi Scotty, I have a 2009 Ford F-150 XLT with the 5.4L 3V V8 engine that has 108,000 miles on it. Recently I went to start the truck and it hesitated to crank but started. Immediately after…

DeadHead

Hi Scotty,

I have a 2009 Ford F-150 XLT with the 5.4L 3V V8 engine that has 108,000 miles on it. Recently I went to start the truck and it hesitated to crank but started. Immediately after starting the check engine light and wrench light came on and the truck went into limp mode. The only code posted was U0300.

Now when I go to start the truck it short cranks with no start. I tested the battery before starting the truck and it shows 12.6 volts. When I turn the key and try to start the truck, the battery immediately drops to 11.8 volts. I can start the truck with jumper cables but it is still in limp mode.

The other issue I am having is with fuse 17 that controls the door locks. Something is causing it to blow so all of my doors have to be manually locked and unlocked. I replaced the fuse and all the doors would lock/unlock as they should but shortly after the fuse would burnout.

(There is an aftermarket radio and subwoofer. It was installed by the previous owner. I installed a spectre cold air intake.)

I have cleaned the MAF sensor and have made sure all cables are plugged in correctly to the PCM, and have tested the battery. I also tried clearing the PCM to see if that would resolve issue but it did not resolve the issue.

Again the only code I am getting is U0300.

Any help and direction on how to troubleshoot and fix is greatly appreciated.

Andrew (DeadHead)