What causes a SPN 985 code?

SPN 985 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 985 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 985 active.

How do I fix SPN 985?

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 985

J1939 SPN 985 — Engine Management parameter

What it means

Engine Control Module Parameter Memory Error. This code indicates that the ECM has detected a checksum error or corruption within its internal configuration or calibration parameters.