What causes a P2255 code?

P2255 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 P2255 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2255 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

P2255

NOx Sensor Heater Control Circuit Low

What it means

The engine control module (ECM) monitors the heater circuit within the NOx sensor. This fault triggers when the detected voltage is below expected parameters, indicating an open circuit or high resistance in the heater power supply.