What causes a SPN 4172 code?

SPN 4172 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 4172 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4172 active.

How do I fix SPN 4172?

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 4172

Cummins fault code 4172

What it means

Aftertreatment Intake NOx Sensor - Data Erratic, Intermittent or Incorrect. The ECM has detected that the Intake NOx sensor signal is not changing or is not plausible compared to other engine parameters.