2005 F250, 6.0. Repair shop was stumped but billed me $550 for doing nothing but changing batteries. Thieves. The ever ubiquitous crank no start syndrome has let the truck sitting for nearly two years now. No shop will work on it but they will let it sit in their lot for weeks... just in case they get some spare time, I guess.

Engine ran until it didn't. After market alarm and engine immobilizer bypass are DEI/Python. The system worked and still kind of works. The remote start will cause the engine to crank for a few seconds, not nearly long enough to actually start it. Alarm is 871XP and immobilizer bypass is 556U.

Same chipped keys as always. Valet switch activator broke off, new switch will be here in a few days. There is NO antenna near the ignition switch and from appearances there never has been. No idea how the ignition key code can be verified if there is no way to read the key. Engine will crank when key is turned.

No fuel pump noise, no injector clatter. FICM relay is operating, glow plugs cycle. No error codes detected by analyzer, Scan Gauge or SnapOn.

My intuition is that the problem is electrical and likely related to the 556U. I don't know how to test that other than to replace it.

Truck has 51,000 miles on it and I am skeptical that there is a mechanical malfunction. I suspect that if I could get past the engine immobilizer that the forward fuel, the life pump, and the injectors might work and that the engine could start.

What do you guys think? Is it logical to diagnose electrical first? The truck is a natural born battery killer... or more likely, the alarm system is the battery killer. The original system had a Loran tracking system but that has long since been removed, somewhere back around 2013, I had a thread about it back then.

Maybe I should call an auto locksmith and see if they can do anything?

 

If the fuel pump isn't activating and the injectors aren't doing a quick buzz test, you've got an electrical issue for sure. Can't say what for sure, but I'd definitely say that whatever is keeping those two things from happening needs to be addressed before anything else.

I hate adding aftermarket alarms to anything, as every one I've ever seen eventually causes a headache. My family and I have had 3 separate vehicles, all used, that had aftermarket alarms on them that eventually failed and would not let the vehicle start. The solution was to remove the alarm system.

Oddly enough, non-alarm remote start/keyless entry systems have NEVER given me an issue.

 

When thinking about removing the alarm and bypass system, would you think that I could just trace the install instructions backwards and reconnect wiring was diverted around relays or solenoids? The thought of doing more harm than good is ever present.

I never liked the system and used the valet system to disable it. No idea when the valet button broke off but it seems like it ought to be the first place to begin in tracing out why the sudden CNS problem. If there is a schematic it might show whether is a simple make or break arrangement. At that point and discover what was activated or deactivated by the switch. That is also the same button that is used to program the remote start "key" FOB.

Another dilemma is that it is reported that f250/350 in 2005 were not equipped with the engine immobilizer system. Were that the case it might explain why there is no antenna in the steering column proximate to the ignition switch. So, the 556U was supposedly installed to avoid conflict with the existing OEM system, it there actually was one.
In consideration of that I disconnected the 556u from the system and cranked but no luck. Had to remove the fuse block just to get to the alarm controller and bypass unit. It's not so bad trying to reach up in there with that out of the way.

 

There is no antenna to send an RF signal to the 556U.

 

The key cylinder is pretty obvious, I think little wire in lower part of the image is what makes the chime go when your key is in the ignition. The white that is on the column is secured with two tori bolts and has a prominent prong, ah shucks, something sticking out that is intended to move something inside of that white box. When I tried to move it by hand it was not so easy to move. I did not open it up, yet. Suspicion is hounding me to see what it is and why is difficult to move. Maybe someone knows what it is and what it does?

 

New Valet switch may arrive tomorrow but more likely on Monday. Ordered a brand new 556U kit, for $20, that includes a ring antenna for the key cylinder and will follow up once those I get those installed.

 

It might help to take this to the 6.0 forum if those don't work. Next steps would be getting some diagnostic info using some kind of scan tool (I use a bluetooth OBD adapter and Forscan).

 

New Valet switch did not accomplish anything though it may be useful if I have to try to reprogram the alarm system. Also substituted in a new 556 bypass module, to no effect.

Guess I need to get a decent crimp tool and start removing the viper/python system. For starters (sorry, couldn't resist) I'm thinking of just cutting and splicing wires that are specific to the front side of the ECM and checking progress by listening for injector clatter rather than cranking a system has been defeated.

None of the locksmiths I spoke with would touch it. As soon as I mentioned the security system they started naming off shops that install the security systems. The nearest shop is at least 30 miles from where I am so that is out of the question.

If anyone can recommend specific wires that go to the ecm, that would be appreciated. I have the install instructions and will try and trace everything out and see what the least invasive alterations may be helpful instead of just unplugging everything.

 

After read and rereading it seems clear that the 2005 F250 series did not have an immobile system from the factory. An immobilizer was installed with the security system but only because the remote start feature required it in order to not defeat an OEM system... which isn't even on the truck.

The only security you had/have is the RF keys. I don't know what the key you put in the ignition was compared with but evidently there is a transponder that can pick up the RF from the key and then compare that with a value that is stored on the PCM or the transponder, itself. This is to say that you could not just get a key from anywhere and copy the factory provided key. It would not activate with the transponder/receiver and not be able to start the truck.

After looking through the shop manuals I still have not located any reference to the transponder. Does anyone know where it is? Is there a service provider who can modify the PCM or ECM such that any duplicate key will work?