What causes a SPN 6104 code?

SPN 6104 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 6104 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 6104 active.

How do I fix SPN 6104?

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 6104

Cummins fault code 6104

What it means

Crankcase Heater Control Circuit - Voltage Below Normal OR Shorted to Ground. The ECM detects a low voltage condition on the heater control circuit which indicates a short or an open circuit.