What causes a SPN 958 code?

SPN 958 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 958 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 958 active.

How do I fix SPN 958?

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 958

J1939 SPN 958 — Engine Management parameter

What it means

Aftertreatment 1 Particulate Trap Differential Pressure. This code indicates the ECM detects an implausible pressure drop across the Diesel Particulate Filter.