What causes a SPN 3780 code?

SPN 3780 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 3780 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3780 active.

How do I fix SPN 3780?

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 3780

J1939 SPN 3780 — Body/Chassis parameter

What it means

Data Link Rate of Update Error - Body/Chassis. This indicates a communication timeout or invalid data received via the J1939 network regarding specialized body equipment status.