P0573 — Brake Switch “A” Circuit High #

Note: The description for code P0573 may vary depending on the vehicle manufacturer. Always consult OEM documentation for your specific vehicle.

• Brake Switch “A” Circuit High (Generic/OEM Standard)
• Brake Pedal Switch Circuit High (Ford, GM)
• Stop Lamp Switch Circuit High (Honda, Toyota)

Summary of the P0573 Code #

When a vehicle’s OBD-II system triggers code P0573, it means the Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a high voltage in the brake switch “A” circuit. This circuit monitors the brake pedal’s electrical switch, which signals when the pedal is pressed. If the voltage reading is higher than the expected range, the ECM logs this code. The brake switch is essential for functions like brake lights, cruise control disengagement, and transmission shifting. A fault here can have both safety and drivability implications.

Common Symptoms for Code P0573 #

When P0573 is present, symptoms can range from subtle to obvious. The vehicle’s safety features may be compromised, and some driving conveniences may not function correctly. Here are the most frequent signs:

• Brake lights remain on even when the pedal is not pressed
• Cruise control fails to engage or disengage unexpectedly
• ABS or traction control warning lights illuminated
• Hard or delayed shifting (in automatic transmissions)
• Check Engine Light (CEL) is on
• Battery drain if brake lights stay on for extended periods

Probable Causes for Code P0573 #

Several issues can trigger a high voltage reading in the brake switch circuit. The following causes are listed in order of frequency:

1. Faulty brake pedal position switch (often called the brake light switch)
2. Wiring harness short to voltage in the brake switch circuit
3. Poor electrical ground connection at the switch or related connectors
4. Damaged or corroded connector pins at the brake switch or ECM/PCM
5. Aftermarket electrical accessories improperly tapped into the brake circuit
6. ECM/PCM internal fault (rare)

Step-by-Step Diagnostic Procedure for P0573 #

Diagnosing code P0573 requires careful inspection and methodical testing of the brake switch circuit. Follow these steps:

1. Verify the code using a scan tool; clear and see if it returns.
2. Check brake light operation — do they stay on or not work at all?
3. Inspect the brake pedal switch for signs of damage, sticking, or misalignment.
4. Test voltage at the brake switch terminals (should match OEM specs, usually 12V supply and varying output).
5. Check for shorts to voltage in the switch wiring using a digital multimeter.
6. Examine wiring harness and connectors for pinched wires, corrosion, or loose connections.
7. Test ground connections for continuity and cleanliness.
8. If all else checks out, consider PCM/ECM testing or reprogramming (rare).

Possible Repairs for P0573 #

The appropriate repair depends on the root cause. Here are the most common fixes linked to the probable causes above:

• Replace faulty brake pedal switch with an OEM or high-quality aftermarket part
• Repair or replace damaged wiring in the brake switch circuit
• Clean or repair corroded connectors at the switch or ECM/PCM
• Restore proper ground connections (clean, tighten, or reattach as needed)
• Remove or reroute aftermarket accessories interfering with the brake circuit
• Reflash or replace ECM/PCM only if all other avenues are exhausted and verified

Can You Drive with Code P0573? #

Limited/Not recommended. While the vehicle may still be drivable, code P0573 should not be ignored. Since it can affect brake light operation, cruise control, and even transmission shifting, there are both safety and legal risks. If brake lights are stuck on or non-functional, other drivers may misinterpret your actions, increasing accident risk. Always address brake system codes promptly.

Vehicles Most Commonly Affected by P0573 #

While this code can appear in any OBD-II equipped vehicle, some makes and models see it more frequently due to design or age-related issues:

• Ford F-Series, Fusion, Focus
• Chevrolet Silverado, Malibu, Cruze
• Honda Civic, Accord, CR-V
• Toyota Camry, Corolla, RAV4
• Dodge Ram, Charger
• Hyundai Sonata, Elantra

Common Mistakes & Best Practices for P0573 #

It’s easy to overlook certain factors with brake switch issues. Avoid these pitfalls and follow good diagnostic habits:

• Replacing the brake switch without testing — always verify the switch is at fault before replacing.
• Ignoring wiring and connector checks — many issues arise from damaged wiring, not the switch itself.
• Overlooking aftermarket device interference — alarm systems or remote starters often splice into brake circuits.
• Neglecting ground connections — a poor ground can mimic a circuit high voltage fault.
• Failing to clear codes and recheck — always clear DTCs and confirm the repair resolved the issue.

Quick FAQ for P0573 #

Still have questions? Here are some fast answers to common concerns:

Q: Will my car fail inspection with P0573 present?
A: Yes, in most regions, an active Check Engine Light or brake light fault will result in a failed inspection.

Q: Can a bad brake switch cause other codes?
A: Yes. A faulty brake switch can trigger codes related to cruise control, ABS, and even transmission shifting issues, depending on the vehicle.

Q: Is it safe to bypass the brake switch?
A: No. Bypassing the brake switch can disable critical safety features, including brake lights and cruise control disengagement, creating a hazardous situation.

Q: How much does it cost to fix P0573?
A: Most brake switch replacements are inexpensive, typically ranging from $20 to $100 for parts, plus labor if you’re not doing it yourself. Wiring repairs may cost more if extensive troubleshooting is required.