What causes a SPN 525 code?

SPN 525 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 525 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 525 active.

How do I fix SPN 525?

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 525

J1939 SPN 525 — Engine Management parameter

What it means

SPN 525 refers to the Transmission Requested Gear or Engine Configuration Map. It indicates the ECM is receiving invalid or missing data from the transmission regarding which gear is requested or which torque map should be active.