Thank you I will check the bolts when I get home from work

 

Bolts are tight still the same thing where I disconnect the battery for a while and then hook it back up it will start then stall

 

 

So where do I go from here

 

I would start by checking the three fuses shown on the schematic. If they are good I would switch the relays around and see if there is a change. Then I would take the fuse box apart and inspect the connections inside. Then I would start taking harnesses apart. It narrative says either a short to ground or power will stop the communication. I have found most can communication problems at major harness connectors. I take them apart and inspect and add some dielectric grease.

 

Fuses are good, switched the relay and no change, connections in all 3 fuse boxes are good, took the harnesses apart and everything looks good to me. I’m getting to the point of giving up on the car and getting rid of it

 

Most shops would not want to tackle this type of problem. It would be a time and material type of repair now that the car is out of warranty. I am a professional mechanic and I just repaired one of these at work on a 2014 F350 with 200,000 miles on it. But that is why I have this job. Problem solved!

 

If it successfully starts then stalls, that would indicate that the ignition cylinder, portion of the BCM that handles security, and the ECM are communicating properly at least initially. Otherwise the vehicle would not start.

CONJECTURE
It seems that to solve this, you will need to know in what order the can communications occur between which modules. I'm taking a wild guess here, but if it is a true can Network failure or lack of communication, you should be able to determine the offending device by figuring out exactly what module is making it stall. My guess would be either the ignition control module or whatever controls the fuel injectors which I'm guessing is the ECM but not sure. I don't know that either of the two actually has the ability to communicate on the can Network. Andy's manuals may indicate what all of the different modules are, which should help focus us on where the problem can be.

Seems like it is cutting fuel or cutting spark. If it was cutting fuel you should sputter stall. If it is cutting spark you should stall sharply. In theory.

Andy, I know that more than one communication can occur at a time on a CAN bus Network, but do your manuals list the sequence of which modules talk to which other modules at and right after start up? There must be some default initial sequence.

Here's something else fun to try. Locate the BCM module in your vehicle. Have a friend heat it with a hair dryer while you are trying to start it. Do not torch the thing, just get it pretty warm and see if the vehicle behaves differently. Not necessarily better, but differently.

Locate the ECM under the hood and do the same. The ECM has a huge heatsink on it from what I remember and will probably be difficult to heat up too much. All you are looking for is a change in behavior at start. It would not surprise me if some of these modules that speak on the can network are integrated into the BCM or ECM. The fact that your vehicle will start after you disconnect the battery for a while means you are completely draining the circuits in all of the electronic modules. You are also letting things cool off. Do a quick test by pulling the battery off, waiting 20 seconds then reattaching in attempting to start. This way we will know whether it is heat or electrical issues that are in play here.

 

I suspect the bcm is going into anti theft somehow. The bcm causes most problems on these cars, I think the total odometer mileage is the common first failure indicator. The car will run without a bcm. The car will not start without a bcm. If you can get the car to start for a few seconds then be ready and disconnect the bcm and see if it continues to run. I have run one of my L200s as a test and swapped the bcm with it running and watched the odometer reading change. I tried to restart the car and it would not start with the different bcm but started right up after swapping back to the original. There is a relearn procedure for a used bcm.

 

That was one of my first thoughts and replies. I understand the security light may not function properly if the BCM is compromised, but given that the code he has is apparently for something legitimate, I just don't know. Modules losing communications is at least potentially consistent with that code being present.

I am quite surprised to learn that L cars will continue to run if the BCM is removed right after startup. If for no other reason then security is retested constantly. I guess it runs because the BCM is the module initiating that constant security check, and it is no longer there.

Does security kill spark and fuel or just spark? You could check the injectors with a noid light, no? Not sure how to test coil on plug spark. I guess you could pull one while it is trying to start and see if the spark disappears while still cranking.