What causes a P1862 code?

P1862 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 P1862 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1862 active.

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

OBD-II

P1862

Upstream NOx sensor power status low monitor fault

What it means

The Engine Control Module (ECM) or Aftertreatment Control Module (ACM) has detected that the battery supply voltage to the Upstream (Pre-SCR) NOx sensor is below the minimum threshold.