What causes a SPN 476 code?

SPN 476 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 476 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 476 active.

How do I fix SPN 476?

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 476

J1939 SPN 476 — Fuel/Air parameter

What it means

A generalized J1939 fault indicating a mismatch in the fuel-to-air ratio parameters, often associated with secondary engine protection systems or emission control feedback loops.