What causes a P1860 code?

P1860 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 P1860 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1860 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

P1860

Upstream NOx sensor O2 signal-related data not available fault

What it means

The engine control module is not receiving the expected Oxygen (O2) concentration data from the Upstream (Inlet) NOx sensor, which is required for calculating SCR efficiency and DEF dosing.