What causes a SPN 371 code?

SPN 371 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 371 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 371 active.

How do I fix SPN 371?

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 371

J1939 SPN 371 — Fuel/Air parameter

What it means

SPN 371 indicates a generic or specific deviation in the expected fuel-to-air ratio parameters as communicated via the J1939 data link. It often points to a mismatch between commanded fuel delivery and actual air intake signals.