Question Submittal to Justanswer

DRW/ Darrell R. Word, PhD, PE 14 Mar 2017 drw p 1 / 3

Question Submittal to JustAnswer.com ----

Hello,

This is D. R. Word. I have some further questions regarding my Ford Truck:

2008 Ford F250 SD 4wd v8 5.4L (VIN: 1FTSX215X8EE54636).

In September 2017, I discussed my problem issues with Eric Remington, and you have the records of the dialog related to that. I very much appreciate Eric, who was quite helpful to me; and, it is certainly fine if Eric is available for my added questions. If not, perhaps some other person that is familiar with the OBDII system, etc., for my vehicle might can help me OK.

To clarify my situation, I have been working on my truck problem on an intermittent basis since my earlier visit with Eric. With Eric's help and my study and experimentation thus far, I have made substantial progress in reducing and narrowing the problem definition (educating myself), but I still have not solved the problem. I will describe here a fairly brief and concise account of the present state of the matter; and, I presently have some fairly concise questions that I need to ask.

You have the initial history; but, in short, the problem is that the Truck suddenly failed to crank. I attempted to troubleshoot the PATS system, and in particular the Transceiver/Antenna module that reads the Key Code. However, I presently have not

determined for sure whether or not the Transceiver is working. Actually, I have not yet been able to locate the Transceiver, which should be in the upper steering column, near the ignition switch assembly and the Key. I then discovered that the OBDII scanners that I have been able to try thus far (four of them in all, of very good consumer grade scanners) will not connect to the vehicle. And, of course, I have not been able to take any advantage of information an OBDII scan.

Since the Key Code is likely supposed to be communicated from the Transceiver module to the ECM in order for the vehicle to start, I chose to focus on the likely failure to do this, given the OBDII scanners cannot communicate. Thus, I chose to switch my focus onto the communication problem, assuming that and the failure to crank are more likely to have a common cause than two independent causes.

My work has also been drastically hindered by not being able to obtain sufficient documentation for the related computer network systems for my truck. I have done substantial testing to discern the information some useful information on the system. This includes a very thorough check of fuses and power supply voltages, where I have been able to identify where and what is pertinent; and I have examined the OBDII port connector (DLC) with a VOM and Oscilloscope, in attempt to assess their condition as best I can. I have experimented with various conditions in which certain system components were temporarily disconnected, etc., and have searched for obvious system damage or visible evidence of a fault. In many cases, I find the frustrating situation that the documentation that I AM able to obtain does not really seem to apply to my Truck. In any case, although it is certainly possible that I am mistaken about some of my present notions, but I think I have narrowed the likely range of causes.

Presently,

(1) The Truck will not start (an will not crank). I have three transponder Keys that did work, but presently do not.

(2) My OBDII scanners will not connect. I suppose this suggests either faulty transmission via available Bus(s), or ECM is not responding to the scanner.

(3) The PATS Transceiver/Antenna operation is still uncertain; but, I am for the moment assuming it is OK.

(4) Fuse and Voltage checks indicate that power is available for systems that I have identified as pertinent. All fuses present check OK. There are some blank fuse spaces that seem not to be pertinent.

(5) The OBDII connector appears to have active connections for 3 Buses: HS CAN pins (6,14), LS CAN pins (3,11), and K-line pin (7). The DC rest voltages and resistance measurements appear to be OK on all of these, and on the CAN Buses, I can observe what appear to be valid signal wave forms with plausible behavior and Frame length, etc.

(6) the ECM might be suspect, but I have no direct evidence that it is faulty. There is substantial effort and cost needed to change the ECM, so I am first trying to get a better handle on possible other causes.

Answers to the following questions would be of great help to me in figuring this out:

(A) If the PATS thinks it has a Theft attempt condition, and the Teft Light is flashing fast, does it become necessary to RESET the system in some manner in order to restore normal operation? And, if so, how is this done? In my attempts to answer this, I have found numerous event accounts and stories from many sources with strong claims of every potential answer of this question. In the range of answers, there are claims of RESET processes that consist of a specific sequence of actions with the ignition Key in coordination with the Theft Light behavior; there are claims that nothing needs to be done; there are claims that the vehicle must be towed to the Ford dealership to do the RESET with special tools; and there are claims you cannot do anything -- just have to salvage the vehicle. I feel pretty sure there is a reasonable and sane answer to to this question.

(B) If the PATS detects a Theft condition, does it in some manner block the OBDII communication intentionally? A local Ford dealer Service Manager, together with his boss, assured me that the OBDII communication is in no way affected by a Theft detection. But I still wonder if such a thing might be happening, which would probably explain my symptoms. My web search attempts on this have yielded nothing definitive.

(C) What network Bus (of the three I have identified) handles the Key Code communications from the PATS Transceiver and the ECM?

(D) More generally, can you possibly provide me with network Circuit Diagrams that define the complete network Bus system for all three Bus types used, and with ALL of the connected Sensors and Activator devices that reside on each Bus?

Hopefully, such diagrams would also show the physical connector locations in the circuit (in order to know which connectors can be used to isolate various portions of the network in testing.

(E) A tabular list of all network devices and Bus association could also be very useful, together with, or in lieu of, the Circuit Diagrams. Can this be provided?

(F) Can you provide circuit diagrams for the two Fuse Panels, showing circuit connections for Fuses and Relays and Diodes, etc.? The two panels in this case are (a) In engine compartment, driver's side, next to fire wall and brake master cylinder; and (b) In cabin, passenger side, side wall, under the dash.

(G) Can you please tell me, or show me, precisely where the Key reading Transceiver/Antenna module resides in the steering column mechanism? I expected it to include a round coil antenna encircling the ignition switch key tumbler, and if not there, some visible and well defined coil antenna in fairly close proximity to the ignition Key when in place. There is in fact no visible coil encircling the tumbler, near the Key., and I have not yet been able to identify anything in the upper colums in the vicinity of the key. Auto parts stores list and sell a "Transceiver" for my vehicle, and the pictures of it look like what one might expect, including a black plastic ring enclosing the coil antenna. But I see no place in the works in the steering column where that said part would fit, and I see nothing that looks like it. Please comment and clarify this for me if you can.

(H) Finally (for now), Can you recommend a practical test or set of observations by which to determine if the ECM module is probably OK? Mine is obviously functional at least in part; but it could still have some particular localized aspects (a bus driver sub-circuit, etc.) that is failing, while most of the computer is OK. I have attempted to find a place (starting with the Ford dealers) to which I could take just the ECM module for test and verification of at least primary functions. But the answer is that I have to bring the whole vehicle. I am supposing there might be some characteristic symptoms that are evident and observable in dash lights or instruments; or in certain other functional abnormalities. Any comments you can make on this would be appreciated.

I will stop here and submit this. I will probably have a few more questions later; but answers and comments on these items will be very useful to me at the moment.

My best regards to you,

Darrell