What causes a SPN 595 code?

SPN 595 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 595 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 595 active.

How do I fix SPN 595?

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 595

J1939 SPN 595 — Engine Management parameter

What it means

Cruise Control Set Speed Limit Error. The engine controller has detected that the cruise control is attempting to set a speed that exceeds the programmed safety or legal limits in the ECM.