What causes a SPN 5320 code?

SPN 5320 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 5320 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 5320 active.

How do I fix SPN 5320?

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 5320

Cummins fault code 5320

What it means

Aftertreatment 1 Diesel Exhaust Fluid Dosing Unit - Abnormal Rate of Change. This indicates the ECM detected that the DEF dosing valve is not responding correctly to commands or is unable to maintain the commanded flow rate.