What causes a SPN 4732 code?

SPN 4732 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 4732 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4732 active.

How do I fix SPN 4732?

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 4732

Cummins fault code 4732

What it means

Aftertreatment 1 SCR Catalyst System Out of Calibration. This code triggers when the engine ECM detects that the SCR system's NOx conversion efficiency is not responding correctly to the amount of DEF being injected.