The wire is a shielded twisted-pair with a drain (SAE J1939/11). 

The wire seen here is the stock wire.   It's comically unkempt.   Note that the orange wire is about five inches too long, so that it must be doubled-back to make it the proper length.   Also, the shielding is missing from the first six inches, and the last four inches.   Neither of these is a problem from a functionality standpoint.  I mean, it probably doesn't hurt anything.  It's just sloppy.  That loose twist of shielding provides no benefit, so why did they leave it loose like that? 

This is what I made to replace it.    All new wire and connectors. 

It was hard to find a short length of J1939 wire.  I found a few sources  that were happy to sell me a 250ft spool, but I wasn't happy enough to buy it.  I found a guy on ebay selling teflon/silver shielded twisted pair.   $35 bought me 25ft.   I wasn't trying to get silver.  In fact, I wouldn't have bought it if I had realized that this is what it was.  However, this is remarkable wire, so I'm going to give it a try.   It's temperature rated to 200ºC.   I don't know if it's oil rated.