I have browsed the S Type threads and found some close to my situation but not exactly. First some background then I'll get into the details of the current issue. This car has had ABS(Rt/Rr WSS) and Parking Brake faults since I got it but have not posed any issues to this point. This is a secondary vehicle so I haven't given those things high priority yet.
Last November I had the transmission rebuilt and a full tune up done. Before this and after it would sporadically die very briefly while driving. It was like you turned the key off and right back on within a second or so, if that. This was completely sporadic and I could not put a pattern or set of conditions to it at all. Then one day in April I got in it, turned the key and got nothing. Everything lit up and operated like normal except there was not even a click from the starter. After determining that the starter circuit was ok I discovered the ECM was not responding to my scan tool. I tried two that I have from when I owned a repair shop then bought an iCarsoft for JLR only. That one shows 13 modules responding but no ECM. The modules that do respond all show communication faults with ECM. I disconnected the ECM and checked for power, ground and network integrity at the vehicle harness. All testing good, I then ohm'd the CAN lines from the ECM connector to the DLC. I had 120 ohms at the DLC with ECM disconnected and 60 ohms with it connected. CAN lines showed no short to ground or power and ~2v when backprobed with key on. ECM power supplies show within 0.2v of battery voltage when backprobed(13.1 & 12.9). Yesterday I finally went into transmission and cluster modules to view data. In the cluster I noticed for "Key in ignition signal" it said False but recognized the master key in the ignition and responded properly as I toggled the key to and from the run and crank positions. It also showed "Transmission not in Park" as True. In the transmission module and on the shifter it showed the gear selection correctly on the module data and on the j gate light indicators. This one has me stumped pretty good. Any suggestions and advice are greatly appreciated. This is an old car but it is in otherwise immaculate condition and a dream to drive. Sorry for the size of the pics I tried to crop and resize them and they would become unreadable for some reason. Thank you all for anything you can offer!
ABS Codes: B2141, U2523,U2522,U2012,C1165,C1235
TCM Code: P1797
Cluster Code: U1027

 

Could this discrepancy be as simple as the infamous loose/missing mount bolts where the shift cable attaches to the side of the transmission?

 

Been through that and its all good. The gear position PID in the TCM coincides with the actual position when I move it too.

 

"Transmission not in Park" as True

Looks worrying.

 

I may be in left field, as I do not know where the TCM gets feedback. With that said, are you positive this position data you’re seeing comes from inside the transmission (downstream of the shift cable) and not the shift lever?

 

Yes, I was looking at TCM data PIDs and watching the changes there as well as the Cluster showing "In Park" and "Not in Park".

 

Update: I tried to use my IDS and VCM2 to no avail. I would like to access PATS and possibly perform the immobilization routine but cannot see that as an option on my iCarsoft tool. So far the iCarsoft is the only tool that will communicate with the available modules on the car.

Could the PATS make the ECM shut down and go offline?
Current PATS codes: U1900,U2523

Current cluster data:
Ignition off/unlock switch: No(toggles properly)
Ignition crank: No(toggles properly)
PATS number of keys supported: 3
Gear selector not in park: True (TCM and J gate show correct gear selection)
PATS status enable/disable: Enabled
PATS master key present: Yes
PATS PCM verification: No
Battery Voltage: 12.7

 

The iCarsoft appears not working correctly. Try a simple tool like an elm327 as it's likely to see the PCM (ECM).

If you have a PATS problem it flashes a code via the PATS light. Read up on that and it looks like you don't have such a problem.

 

I am thinking it may be a PATs issue but I so far cannot get any scan tool in my arsenal to connect to PATs and do anything more than show fault codes and data.
I have an ELM327 for use with Forscan. Is there a free or reasonably priced download similar to Forscan for this vintage of Jaguar?

 

Is it flashing a code? If not, it's not a PATS issue.

 

Yes post back what the PATS light is doing.
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