Code Definition

B0037 — Auxiliary switch circuit shorted to Earth

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

About B0037

B0037 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 B0037 is stored, the module has detected 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 B0037 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

The control module, typically the Body Control Module (BCM), monitors the auxiliary switch input to know when that switch is operated, usually by watching the signal voltage rise and fall as the switch opens and closes. DTC B0037 sets when the module sees the auxiliary switch circuit held at a continuous low voltage consistent with a short to ground or earth, so the input appears permanently active even when the switch is released. Depending on the function assigned to that switch, the affected accessory or feature may operate constantly, fail to respond, or behave erratically. The module stor...

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