What causes a SPN 4284 code?

SPN 4284 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 4284 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4284 active.

How do I fix SPN 4284?

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 4284

Cummins fault code 4284

What it means

Aftertreatment Intake Temperature - Data Valid But Below Normal Operating Range - Moderately Severe Level. This code indicates the SCR intake temperature sensor is reading lower than expected for the current engine operating conditions.