What causes a SPN 3237 code?

SPN 3237 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 3237 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3237 active.

How do I fix SPN 3237?

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 3237

SPN 3237 FMI 3/4/5 Aftertreatment 1 SCR Intake Gas Sensor Power DTC

What it means

This fault indicates an electrical circuit problem with the power supply to the Selective Catalytic Reduction (SCR) intake NOx sensor.