Code Definition

C0040 — Brake Pedal Switch ‘A’ Circuit

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

About C0040

C0040 is a generic (obd-ii standard) chassis diagnostic trouble code. It belongs to the C-prefix family of codes, which covers chassis, braking, steering, suspension, or stability-control faults.

When C0040 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: Chassis (C) codes are stored in the ABS, traction control, or stability-control modules. An enhanced or OEM-level scan tool is usually required to read and clear them.

Because C0040 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 Antilock Brake System (ABS) or Body Control Module (BCM) monitors the brake pedal switch A input to confirm brake pedal application and release. DTC C0040 is set when the module detects an electrical fault in the brake pedal switch A circuit, such as an open circuit, short to ground, short to battery, or a signal state that does not correspond with expected brake pedal operation. The brake pedal switch reports pedal position to several systems, so the module uses this input to coordinate braking and related functions. This fault indicates the module cannot reliably determine brake pedal st...

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