What causes a P0438 code?

P0438 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 P0438 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0438 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

P0438

Catalyst Temperature Sensor High Voltage Bank 2

What it means

The Engine Control Module (ECM) has detected a high voltage signal from the Bank 2 catalyst temperature sensor circuit, typically indicating an open circuit or internal sensor failure.