P0573
Generic (SAE) Basic entry
Brake Switch 'A' Circuit High
Severity
Medium
Typical repair cost
40 – 350 EUR
System
Powertrain
What it means
P0573 is stored when the engine control module measures a voltage in the Brake Switch 'A' circuit above the expected maximum, typically because the signal wire is shorted to battery voltage or the circuit is open and pulled up internally.
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Symptoms
- Check engine light on
- Idle too high, too low or hunting
- Stalling when coming to a stop
- Speedometer or cruise control not working in some cases
Common causes
- Damaged, chafed or corroded wiring in the Brake Switch 'A' circuit
- Corroded, loose or water-damaged connector terminals
- Failed Brake Switch 'A' component (sensor, solenoid or actuator)
- Poor ground connection for the module or component
- Faulty control module driver (rare, confirm all else first)
How to diagnose
- Read freeze frame data and note when the code set (cold start, under load, after rain)
- Inspect the Brake Switch 'A' connector for bent pins, corrosion and water; wiggle the harness with the engine running and watch live data
- Measure supply voltage and ground at the connector with the key on
- Check the signal wire for shorts to ground or battery and for continuity to the control module
- Test or substitute the Brake Switch 'A' only after wiring and connectors are confirmed good
- Clear the code and complete a drive cycle to confirm the repair
Frequently asked questions
Can I keep driving with P0573?
Usually yes for a short time, but expect reduced performance or higher fuel use. Have it diagnosed within a few days.
Will clearing P0573 fix it?
No. Clearing only erases the stored code; it returns as soon as the monitor runs again unless the cause is repaired.