Please reference:
rotate.aero/forum/ata26-767/319-ata-26-18-duct-overheat
for troubleshooting of a similar problem.
EICAS status message "Right Loop 2"
The system is telling you that one of the two wing duct overheat loops has failed. In the case of duct loops, both loops have to sense a overheat to actually show a warning to the crew. If one loop is inoperative and the other loop senses heat.... it will set off the warning.
Body and duct leak issues are easy to identify the fault, finding it..... can be a major pain in the ass.
The easiest place to start is at the loop test panel on the P61 panel. Both ends of each loop (2 body, 2 left wing, and 2 right wing loops) can be checked from the plugs at the back of the panel.
We checked several loops with a
LCR Meter
. When compared..... all the known good loops checked had resistances over 250K Ohms. Our suspect loop had a meter reading of 1.9K Ohms.
Now comes the fun part of (my favorite three words in aviation) "Gain Access To" the loops themselves. This always involves dropping panels or removing sidewalls.
We checked for a open loop first (pin to pin on the plug). We found the loop still had continuity. If the loop reads good end-to-end, then our issue most likely was a short (or high resistance short) to ground. The measurements above were taken using aircraft ground as a reference. 1.9K Ohms seems high, but the system monitor card showed the loop failed.
To isolate the problem we disconnected the loops midway. Our short followed the inboard three sections. We could read that from the test panel plug. One pin showed high resistance (250K+ Ohm).... the other was still the 1.9K. We had to separate each of the remaining three loops and checked for a short directly at each one.