What causes a SPN 823 code?

SPN 823 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 823 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 823 active.

How do I fix SPN 823?

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 823

J1939 SPN 823 — Engine Management parameter

What it means

Engine Fan Clutch Output Device Driver. This code indicates an electrical failure (short to ground, short to battery, or open circuit) in the circuit that controls the engine cooling fan.