P1652 with Dead Gauges - PCI Bus Questions

Hello, need some help. I've been reading up on the P1652 code "short to ground on the J1850" which deals with the PCI Bus and I have a very specific question: If D25 (PCI BUS) is shorted to ground will the vehicle stop running? Otherwise if a "module" connected to PCI Bus (i.e. gauge cluster or other peripheral device) shorts D25 (PCI Bus) to ground will vehicle stop running or will only the problem module go whack-o?

Vehicle: 2004.5 Ram 2500 4x4, ATS built 48RE, Quadzilla Xzillirader, BlueDriver OBD II reader plugged into OBD II port (was data-logging), otherwise stock

Sequence of Events:

1. Plugged in BlueDriver OBDII reader to data log some temperatures (IAN and ECT).
2. Started truck.
3. Noticed the truck was idling rough before I rolled out of driveway.
4. Went on road trip.
5. About 2.5 hours into trip, driving on I-70 West @ 75 mph, instrument cluster would occasionally "ding" but no lights would illuminate.
6. "ding" with no gauge light occurred 3 to 4 times over the span of about an hour...
7. Then "ding" and all dial type gauges went to zero and various dash lights illuminated (CEL, red security light, etc.).
8. Truck kept running, I was doing 75MPH on I-70 west near Eagle CO.
9. I did not notice any change in performance but for he whole trip the truck seemed to be a bit laggy.
10. Pulled over near a hotel.
11. Turned truck back on and everything went back to normal.
    
12. Used BlueDriver OBDII reader to check codes it had red light which said it could not communicate with bus from OBDII port.
    
13. Removed BlueDriver and re-plugged it in. Again red light on BlueDriver "can't communicate".
14. Removed BlueDriver.
15. Turned truck off and did key 'on-off-on-off-on' yields: P1652
16. Gauge C-Code check yields: AA 07
17. Plugged BlueDriver back into OBDII port and cleared P1652 with BlueDriver OBD II reader, note: disconnecting the battery for 10 minutes did not clear this code.
    
18. Started truck and all was fine. Stopped engine.
19. Inspected wiring harnesses for a while after reading some posts. Specifically I inspected wiring harness from A/C compressor pressure transducer all the way around engine and no wire rubbing/damage was identified.
20. Started truck back up and continued on trip, code never came back.
21. Problem has not recurred in about 500 miles of driving. The only abnormal symptom is the truck will idle rough occasionally. Still feels slightly laggy.

Other issues notices during the "dead gauges" while driving episode:

• A/C quit working (light in the A/C button was illuminated) - assuming the A/C clutch dis-engaged
• Trip odometer displayed mileage but did not increment as I was driving
• Overhead console trip meter displayed mileage but did not increment as I was driving

Any help would be appreciated. Note: I did not remove the Quadzilla at anytime during this episode.

 

Relay, one of the modules ( computer)
You have that relay and fuse box under the hood.

 

The short answer is taking down the bus should never result in the engine dieing. If you shut it off and attempt to restart it may not start.