FYI Cummins 5.9 codes and fix
2000 5.9 200000 miles. On our recent trip I kept getting Scan Gauge code;
ID 190, FM 2 (rpm signal).
I could erase the code with the SG but it would return...About 6 times in 1200 miles. The code would cause a power drop and surging idle until cleared.
I also got 1 fuel filter light that stayed on for a few miles than went out, even though I'd recently changed the filter, there it was.
The 190 turned out to be a bad connection at the multi-pin plug at the rear of the engine. I unplugged and coated the female side with dielectric grease and re-plugged.
The FF was a loose sensor plug at the filter. The scary part about the FF light is that it could indicate a failing lift pump.
Returned today from 250 mile run without codes, with the new radiator the bus run very well.
Don, Mary and Spooky the cat.