What causes a SPN 33 code?

SPN 33 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 33 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 33 active.

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 33

J1939 SPN 33 — Engine parameter

What it means

J1939 SPN 33 is a generic engine parameter fault indicating that the controller has received invalid data or is unable to process a specific engine-related message transmitted over the J1939 network.