DTC P1374 3X Reference Circuit
DTC P1374 3X Reference Circuit 
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
In my helms it's a 3.8 code. "The 3X reference signal is produced by the ignition control modure (ICM). The ICM calculates the 3X reference signal by dividing the crankshaft position (CKP) sensor 18X pulses by 3. This calculation is performed while the engine is running, and while the CKP sync pulses are being received......." I'd look at the ICM connector and wiring first. Sorry not much help....maybe someone can scan/post the diagnostic page for you, it's not very long.
