What causes a SPN 3346 code?

SPN 3346 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 3346 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3346 active.

How do I fix SPN 3346?

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 3346

J1939 SPN 3346 — Body/Chassis parameter

What it means

Engine Cooling Fan Speed - This J1939 code typically refers to a signal issue or data loss specifically concerning the fan speed feedback or body/chassis requested fan control.