What causes a P2238 code?

P2238 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 P2238 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2238 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

P2238

P2238 O2 Sensor Positive Current Control Circuit Low (Bank 1 Sensor 1)

What it means

The Engine Control Module detects that the pumping current circuit for the upstream oxygen (or wideband NOx/O2) sensor is below the expected voltage range, indicating a potential short to ground or open circuit.