What causes a SPN 3660 code?

SPN 3660 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a SPN 3660 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3660 active.

How do I fix SPN 3660?

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

J1939 SPN

SPN 3660

J1939 SPN 3660 — Body/Chassis parameter

What it means

SPN 3660 usually refers to 'Engine Injector Cylinder #5 : Current Below Normal or Open Circuit.' Note: Depending on the specific OEM (Cummins, Detroit, Paccar), SPN 3660 identifies a fault in the Cylinder 5 injector solenoid circuit.