What causes a SPN 520231 code?

SPN 520231 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 520231 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 520231 active.

How do I fix SPN 520231?

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 520231

Fuel Mass

What it means

Fuel Mass Flow Rate Out of Range. This indicates the engine control module (MCM) cannot maintain the commanded fuel delivery to achieve the requested rail pressure or torque output.