Code Definition

B0038 — Auxiliary switch circuit open or shorted to power

System: Body  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About B0038

B0038 is a generic (obd-ii standard) body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B0038 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; and a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

Because B0038 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

This is a restraint system related body code. The SRS (Supplemental Restraint System) control module monitors an auxiliary switch input circuit and sets DTC B0038 when it detects an abnormal voltage on that circuit, consistent with either an open circuit or a short to battery voltage. The auxiliary switch provides a status input to the restraint system, and the module continuously checks the circuit for a valid voltage within the expected range. The code is stored when the reading stays high, indicating a short to power, or drops out entirely, indicating an open circuit, for longer than the ca...

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