What causes a SPN 7987 code?

SPN 7987 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 7987 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 7987 active.

How do I fix SPN 7987?

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 7987

Cummins fault code 7987

What it means

ECM Calibration Memory - Out of Calibration. This code indicates that the Engine Control Module has detected an internal memory error related to the calibration checksum.