What causes a SPN 988 code?

SPN 988 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 988 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 988 active.

How do I fix SPN 988?

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 988

J1939 SPN 988 — Engine Management parameter

What it means

SPN 988 typically refers to the Engine Management Parameter. It indicates a data mismatch, timeout, or invalid signal received by the vehicle controller regarding specific engine operating parameters via the J1939 data link.