P0573 indicates the powertrain control module has detected a voltage signal from the brake switch circuit that is higher than the expected calibrated range. This typically means the brake pedal position switch or its wiring is failing to pull the signal low, or the circuit is shorted to voltage, which can affect cruise control operation and brake-light logic.
Internal contact failure or electrical degradation inside the stop-lamp switch prevents the circuit from toggling states correctly, causing a sustained high-voltage reading.
If the switch is not properly seated against the pedal bracket, the plunger may remain partially actuated or released, keeping the circuit in a high-voltage state.
Chafed, melted, or pinched wires can feed unwanted voltage into the signal line, while an open ground return can allow the PCM input to float high.
Terminal corrosion, bent pins, or poor pin fit at the brake switch or harness connector can create excessive resistance or an open circuit that mimics a failed switch.
Rare; a genuine module failure or corrupted calibration can cause the PCM to misinterpret a normal brake-switch signal as abnormally high.
Yes, the vehicle is generally safe to drive, but cruise control may be disabled and brake lights may behave abnormally, so prompt diagnosis is recommended.
Genuine PCM failures causing P0573 are exceedingly rare; the fault almost always lies in the brake switch, its adjustment, or the wiring. Replacing the module is usually unnecessary.
Yes, a failed or misadjusted brake switch can keep the brake lights illuminated continuously, or conversely prevent them from turning on at all, depending on which internal contact fails.
Yes, poorly integrated aftermarket devices that tap into the brake switch wiring can introduce voltage irregularities or ground disturbances that set this code.