Hey guys, im new to the forum and its been a while since i had a 4.6 my last one was a 98 f150

So i got this expedition for 2k its now driving me absolutely insane. It ran fine for 4 days and i loved it.

The initial problem was a battery light. After scouring the forums i was unable to fix that but was gonna check it more at work today since i didnt have a multimeter at home. I replaced the battery because the batery light was on . The alternator is 4 months old and im not sure what make it is.

after ariving with new problems at work today i tested the voltages. I had 12.10 on a new battery while running. And 12.30 on the battery without running. I pull the negative terminal and the vehicle dies.

So i was leaving for work and i started it up and the check engine light was on. The OD light was flashing.

so now i can tell the vehicle was in limp mode. It took about a dozen cars honking and me and a lot of slow driving to git it to work. It was stuttering and struggling in 3rd and up. Slow to take off unless shifter was in the 1 or 2 position.

Here are the codes that all showrd up at once

Codes p1747 P0755 P0743 P0443 P1451 P0135 P0155 P0141 P0161

I sunk all my money into buyinf this thinf because i needed last minute car after my wife got a new job we couldnt share anymore.
please help.

And thanks everyone

 

Check fuse 11 in the fuse box under the hood.

 

i have checked fuse 11 , it is not blown. Thats was one of the first things i checked. I also checked the single wire plug on the back of the alternator.

 

Then using a meter put one probe to a clean bare metal spot on the engine block and the other to a clean bare metal spot on the body. If the reading is more than 0.5 volts you have an issue with the grounding strap.

 

Everything checks out now. I can see the alternator charging but it needs a new belt tensioner . It only gets to 13.5 v

The truck is in limp mode but doesnt throw any misfire codes. Im reading 0v on one of the 02 sensors from the obd diag.

Could the transmission codes cause the computer to put it into limp mode. Hence the flashing OD light. Im also getinf torque converter codes.

 

13.5v is okay, it just means the battery is charged so the ECM pulled the voltage back to avoid overcharging the battery. Yes, tranny fault codes can cause limp mode.

 

This is not a PCM-controlled charging system. That reading could be 1) completely normal or 1) low because the battery is very low from having been driven without the alternator working. Recommend charging the battery with an external charger to eliminate the second possibility which will also take a large load off the suspect alternator. Most likely, you bought someone else's intermittent "problem" that they gave up on.

You have a blown fuse or open circuit that provides operating power to all of those actuators and sensors. The transmission is limping along in a high gear because the PCM cannot control it. Check fuse F23 under the hood. If blown, find and repair the wiring short to ground (usual cause is O2 sensor wiring on the exhaust).

That procedure is very ill-advised on a modern computer-controlled vehicle unless you like replacing very expensive electronic stuff.