Truck can start just fine, just doesn’t want to….

Greetings. This is my first trip to any sort of forum, so please let me know if I am in the wrong place.

This problem started many months ago with the vehicle failing to respond to my key’s autostart function….Took me maybe two or three tries sometimes to get it to catch. Then more frequently to where it would only catch about 1 out of 5 tries. Two replacement batteries made no difference. If I stood right next to the truck and held my tongue just right (haha) I could make it start. Had to be very deliberate with button pushes. The vehicle would still start with the key in the ignition.
I know what your thinking… the key is worn out…maybe true, but….

In the last 4 or 5 weeks, the truck was getting to where it would not start with the key in the ignition…about 1 out of 10 times failed to turn over. Everything came on and looked normal…no flashing dash lights or anything crazy as others have reported.. just no response to the key except that I hear solenoids clicking. First time it happened, I replaced the battery with no luck.

I got the idea to use the auto start to start it and it worked…for a while. Sometimes it would start on the key, other times it wouldn’t and I would resort to the autostart. At first I was only using my key, but later on I was using both of my keys with the same results.

As of today, the problem has escalated to no start in ignition or with remote key. Tried every combination of doors locked, unlocked, brake pedal, in park, in neutral, etc. No joy here.

These two incidents may be totally unrelated, or not. Ideas???
This is an escalating problem and not an outright failure which has me thinking it may be more mechanical then electrical....or not.

Was hoping for some clue before I suffer the fate of having the dealer tear into it.

This is a 2011 Lariat EcoBoost F150,
vin # 1FTFW1ET7BFC49006, 120k miles.

Thanks in advance
DW

 

Hi DW, welcome to FTE!

So, to be clear...does the engine crank when it fails to start? Or do you just hear it clicking? Does it behave the same way when using your remote start?

 

Hi Tom
With the key in the ignition, there is no cranking. Just a relay picking (somewhere under the dash.. haven't found it yet)
The autostart function is a bit harder to isolate because a failed key press attempt just honks the horn. So I'm never sure if its the key not working or another version of the truck not responding.

 

Update: I read that sometimes disconnecting the battery causes the bcm/ecm/ecu to reset.
Tried it. The engine would not start on the key, but on a second try with the remote start, it did. First time in two days I have been able to get it going.

 

Sounds like a neutral safety switch, but if it's not starting in neutral it may be something else. I think it needs to get scanned for trouble codes first, and possibly diagnosed by someone with a tool that can read PCM input values. There's a list of conditions that are required for the engine to crank, and it sounds like one of them isn't being met.

 

I was thinking that it might be related to the shift interlock, too. After trying to start the truck moving the shift lever back and forth, the rear backup alert started going off when it was in park. Maybe the interlock is out of wack or the transmission just doesn’t care for being messed with without actually shifting gears.
No telling. Guess I will have to have it towed to Ford to have the computer queried.

 

Sounds like a range sensor to me. Definitely should get it scanned before throwing parts at it though, so the Ford dealer sounds like your best option. Make sure to post back with the solution!