Hey everyone,


I purchased a 2007 F150 Lariat with a 5.4 about two months ago. It came from OK and only has 74K so it is cleaner than the trucks in New England that are 4 years old.


My first Ford so just getting to know it. So far I am really happy with the truck.


I ran into a odd problem the other day. I drove to the transfer station shut it off did my recycle and came back turned the key and nothing. Took it out of park and put it back in just to make sure and nothing. Tried Neutral and nothing. Lights headlights on bright so I had power. Only two miles from home so call AAA to get it towed so I could work on it. Was taking a long time getting through so after 10 minutes I tried again and it starts right up.


Brough it home and for the last two days I keep trying and it starts every time.


Looking at wiring diagrams there is the fuse, ignition switch, the relay, and Solenoid. Of course when it is working hard to find the problem. I will keep a meter with me and if it happens again I will be able to check some things.


I did notice that if I bump the starter (like you would if you were trying to line up TDC) it spins the motor to it starts. I also noticed after it is running you turn the ignition to start and it does not engage the starter. So there is a little more going on.


I really appreciate any information are ideas. Have others had this issue?


Gary

 

That is normal on your truck.

You mentioned the usual suspects, also look at the DTRS (neutral safety switch).

 

Your truck is OTIS-equipped.

Here's the list of suspects for a "no crank, no start" fault":

 

Great, thanks for the info. I tried to find out what it was called (OTIS) but had no luck. Now if I can just get it to do when I am home so I can poke around and find what is going on.

 

Have you checked for codes? My 02 truck was intermittently cranking but not starting and it was the relay that powers the PCM. Oops! Yours isn't cranking so never mind.

 

So for the latest. I have tried a bunch of different things to get this problem to happen again. Long trips, short trips, Let it sit for just a few minutes after driving. So today I drove to the transfer station which is about 3 miles away. I pull in empty the recycle (takes about 2-3 minutes), truck will not start! Like last time, tried all the same things, Nothing.

So like last time I waiting about 5 minutes, starts right up. Drove it home, started it a few times no problem. Wait a couple minutes, starts right up. Drove it around the block a couple times, starts right up. Drove it back to the transfer station and then home, starts.

All I can think of is something gets warm and has a problem. It is cold here today (17 degrees) . A three mile drive warms it up but probably not hot. I get to the transfer and shut it off. So maybe it gets a little hotter sitting with no air flow. Once it cools off for 5 minutes it is happy. But driving it around more does not cause the problem. Driving it and letting it sit for a couple minutes does not make it happen.

The transfer station is not a great place to work on you truck. And once I get it home I can make it happen.

I guess I could run wire from the fuse box wire going to the starter solenoid so I quickly check for power when it acts up. That would tell me if it was up stream or maybe the starter (or a bad connection to the starter).

I am going to look around today and make sure nothing is lose at the starter.

Open to all suggestions, this is driving me freaken crazy.

Gary

 

Roadie,

I have been playing with this for a couple weeks now. I had two occasion where it cranked like crazy for 5 seconds, did not fire which is unusual. Then it would not crank at all. It normally starts so quick I did even know it had OTIS. So maybe this is something to look at.

Thanks Gary

 

Here that latest and this very intermittent problem. I had read the ODBII engine codes and there were none. I borrowed a friends Autel meter and read the body codes. I got B1600, B1602, B1681, all point to PATS system problem. I finally got it to fail again and noticed that the anti theft light on the dash was blinking rapidly. I kept turning the key on and watching the light when it finally stopped blinking the truck starts right up. Both good and bad, good to have eliminated a lot of things. Bad that this is not as easy to test as looking for voltage or swapping a relay. I have found a bunch of articles on this problem with Fords. So I have several things to try, I just need to get it to fail. I have about a 10 minute window before it "Gets Better" and sometimes I just can't get it to come back for a day or 2. Once i find this I will let everyone know, maybe save someone else some time.

 

The first thing to try when you think you have a PATS issue is your other key, if you have it.

 

Yep, took it out today drove it about 5 miles and parked. Tried to start got the fast flash and no start. Tried the other key did the same. I have the cover off the steering column so I could wiggle the wires going to the transponder. I couple folks had a lose wire that was intermittent, still no start. I was going to swap the PCM power relay but it started before I got to it.

I swapped it anyway just to see but will have to wait. I also have some cold spray that I can cool off the transponder ring and the PCM. I also read on a another Ford site that this is a common problem caused by bad grounds. So I cleaned all the grounds. Pretty simple (and cheap) thing to do. A couple of them were pretty oxidized.

Need to test it a few time to see if either of these were the problem.

I do have one question, on the older F150s there is a separate PATS module. It sounded like the PATS transponder goes directly to the PCM is later models. Does anyone know if a 2007 F150 has a separate PATS module.

Biggest problem here is you don't know if you fixed it, It is so infrequent

I do appreciate all the advice. Keep it coming.

 

The observation of the fast-flashing THEFT light earlier would have simplified diagnostics.

At the transceiver, check for proper ground on the BK-LB wire and switched battery power (via CJB F28) on the RD-YE wire. If both are good, then it's highly probably your transceiver is failing intermittently.

F150s never had a separate PATS module although other Fords did. Early F150 PATS versions had that feature in the cluster, later models, including yours, integrated that feature directly into the PCM.

 

Yes it would have made this a lot simpler. Never crossed my mind and I had not noticed the light until I read the codes. I have had keys with chips stop working on other cars but they always try to start and quit. Never had one not turn over.

I will check for ground and voltage at the transceiver. Only things I have left other than a bad connection is the transceiver and the PCM.

Thanks

 

Your truck's PATS system includes a starter interrupt. If PATS does not prove out correctly, starter operation is inhibited.

 

Checked out the wiring to the transceiver seemed fine. Purchased a new transceiver from the dealer and installed it. I drove the truck about 4 miles pulled into a parking lot shut it off and no start. Waited about 20 minutes trying it every 5 minutes would not start. This is twice as long as it normally takes.

So I am thinking what is different. I was listening to the radio which I usually do not do. I am usually looking under the hood or at fuses etc. So I turn the radio off and wait 2 minutes, truck starts. This is so random you just don't know if you discovered something or it just got better on its own. I have an aftermarket (Alpine) radio I installed. I know I am reaching here but could the radio cause a problem with the PCM?

My plan is to unplug the radio connections and do the drive to see. Its free and I got nothing to lose.

G

 

You wouldn't happen to have an aftermarket alarm system?