What causes a SPN 5145 code?

SPN 5145 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 5145 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 5145 active.

How do I fix SPN 5145?

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 5145

Cummins fault code 5145

What it means

Aftertreatment 1 Outlet NOx Sensor - High Corrected Value. This indicates the downstream NOx sensor is detecting emissions levels that exceed the expected range for current engine operating conditions.