What causes a P2231 code?

P2231 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 P2231 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2231 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

P2231

O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 1 Sensor 1

What it means

This fault indicates an internal electrical short within the wideband oxygen sensor, where the heater circuit voltage is leaking into the signal wire. This common failure on newer diesel units prevents the ECM from accurately monitoring exhaust chemistry.