What causes a SPN 7343 code?

SPN 7343 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 7343 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 7343 active.

How do I fix SPN 7343?

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 7343

Cummins fault code 7343

What it means

Aftertreatment 1 Diesel Exhaust Fluid Doser 1 Heater - Voltage Below Normal or Shorted to Low Source. This indicates the electrical circuit for the heater inside the DEF injector/doser is not operating correctly, preventing the system from thawing frozen DEF or maintaining temperature.