What causes a SPN 683 code?

SPN 683 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 683 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 683 active.

How do I fix SPN 683?

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 683

J1939 SPN 683 — Engine Management parameter

What it means

The Engine Control Module (ECM) has detected a circuit fault or communication error with the Engine Compression Brake or Glow Plug Relay (Secondary Device). In most modern heavy-duty applications, this refers to a glow plug/pre-heater circuit failure.