I’m new to the forum and F150’s and this is my first post other than the initial welcome one.

I’ve been reading this forum and watching You Tube for this issue, however none of the fixes so far are working for me, so I hope maybe there are some people with more knowledgeable of 10th gen trucks willing to give me some tips.

For background, maybe entertaining, I bought the truck last summer from an estate sale of Robert Monks (I have the original bill of sale too) a somewhat well known attorney/political person who literally wrote the book on the importance of shareholder returns for corporations.

The history was free but I paid $4k for a stock 2001 F150, 6cyl, automatic, 2x4, regular cab, 8ft bed with 50k original miles. Mr Monks used it for landscaping on his estate. It was in great condition with one caveat, the radiator support was rusted through. The mechanic I work with passed it for state inspection last year but said it would need to be replaced as the radiator was held on by a prayer. My mechanic is short a couple guys so had to pass on doing body work, and quotes I got from others seems high, so I decided to do the work myself. Mistake?

So last weekend I parked the truck inside my garage (running perfect) and began the project. Though a pain, I replaced the radiator core support. I decided to unhook my battery because I knew I’d be tack welding some spots and wanted to minimize causing any electrical problems even with keeping my lead close to welding spots (I use a flux core welder), and it was unhooked three days.

When I was done with welding I reattached the battery. I tried to start the truck (both primary and spare keys) and it turned over, but flashes the “theft” light, and then gives a 16 code. The odometer also shows just dashes otherwise the dash is lit and gauges work. I’ve read a number of posts and watched a number of videos dealing with this, none actually fix it for me. My understanding is there is an issue with PATS recognizing my key and or PCM relay.

Is that accurate?

I tried the 10 -15 minute recoding for my key. I have also removed the PCM relay to see if that might help it reset, I also swapped it with the fuel relay (both appear to be original never replaced), I also put my battery on the charger to make sure that was good, and cleaned up battery terminals though they were fine. The one thing which is a little different than what I’ve read is sometimes when I cranked it while trying to fix it, both the PCM and fuel relays were clicking in the key position just before turning over. Could both relays be bad? Or somehow not getting necessary voltage so the PATS doesn’t recognize the key?

While I could have it towed to my mechanic, I figure I made it this far, I should do this too - this must be something obvious but I’m too Ford dumb to know and hoping someone will see what I’m doing wrong and tell me.

Thank you.

 

could just be bad keys

 

Thank you, I thought that. Wouldn’t leaving it on the 4th key position for 15 minutes fix that? If it just had to relearn the key?

 

not if the actual transponder in the key is bad

 

So it’s possible both my primary and spare keys transponders are bad at the same time even though they worked four days ago? Just trying to figure out my next steps.

 

Yea its certainly possible,

 

I would try a new relay.

 

I used to remove the battery and disconnect the PCM before doing any welding on my truck, but I've been getting lazy lately and not doing it. Your story has reinforced my old practice for future work.

 

Yes, total idiot move. It was just a detached ground, I knew it had to be something obvious I just wasn’t seeing.

 

Wow! Glad you sorted it out.