What causes a SPN 3776 code?

SPN 3776 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 3776 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3776 active.

How do I fix SPN 3776?

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 3776

J1939 SPN 3776 — Body/Chassis parameter

What it means

The J1939 SPN 3776 code indicates that the engine or chassis controller is receiving invalid, inconsistent, or missing data regarding a body-specific parameter (e.g., PTO status, dump bed position, lift gate status) over the CAN bus.