P0573: Brake Switch A Circuit High — what it means, the affected system and what to check before replacing parts.
Meaning, symptoms, causes and checks
Brake Switch A Circuit High. Basic catalogue definition; diagnostic details have not yet been reviewed.
Affected system: Powertrain
Symptoms
- Brake lights may remain on with the pedal released or fail to respond normally; either condition requires prompt attention.
- Cruise control may stop working; on some vehicles the Park interlock may also behave unexpectedly.
Possible causes
- Brake-switch A may be misadjusted, worn or internally defective.
- Wiring shorted to supply, damaged insulation or loose and corroded contacts can keep the input voltage too high.
What to check
- Confirm P0573, observing the brake lamps with the pedal pressed and released; do not drive if their operation is unreliable.
- Check the brake-pedal switch mounting, adjustment and plug; inspect nearby wiring for wear and corrosion.
- Compare the scan-tool pedal-switch state with voltage measurements for both pedal positions, then test the switch before considering a controller fault.
Also written as: P0573-00, P057300, PO573 (some scan tools add the fault-type byte, e.g. -00).