What causes a P2438 code?

P2438 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 P2438 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2438 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.

OBD-II

P2438

Secondary Air Injection System Air Flow/Pressure Sensor Circuit High Bank 2

What it means

Indicates the ECU has detected a voltage signal from the Secondary Air Injection (SAI) pressure sensor that exceeds the calibrated limit on engine bank 2. In heavy-duty applications, this often relates to specialized emissions air pumps or auxiliary air systems used for aftertreatment thermal management.