What causes a SPN 676 code?

SPN 676 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 676 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 676 active.

How do I fix SPN 676?

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 676

SPN 676 — Engine Glow Plug Relay

What it means

The ECM has detected a circuit fault (open, shorted high, or shorted low) in the glow plug relay or intake air heater relay control circuit.