What causes a P2239 code?

P2239 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 P2239 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2239 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

P2239

O2 Sensor Positive Current Control Circuit High (Bank 1 Sensor 1)

What it means

The Engine Control Module (ECM) detects a high voltage condition on the O2 sensor's pumping current circuit, indicating a potential short to power or sensor failure.