What causes a SPN 68 code?

SPN 68 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 68 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 68 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 68

J1939 SPN 68 — Engine parameter

What it means

Engine Parameter - Data erratic, intermittent, or incorrect. Typically refers to a secondary engine pressure or load parameter that is out of spec.