What causes a SPN 101 code?

SPN 101 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 101 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 101 active.

How do I fix SPN 101?

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 101

SPN 101 Engine Crankcase Pressure High

What it means

Indicates that the pressure within the engine crankcase has exceeded the maximum allowable threshold, typically caused by excessive blow-by or a restricted ventilation system.