Chevrolet Dtc P0573 – Diagnose And Fix Your Brake Switch High Voltage

ByRobert Lozano

Encountering a chevrolet dtc p0573 code can be puzzling, often indicating an issue with your brake switch circuit. This diagnostic trouble code points to a high voltage signal from the brake pedal position sensor, which can affect crucial systems like cruise control and brake lights. Understanding this code is the first step to a safe and effective DIY repair, saving you time and money.

Picture this: You’re cruising down the highway in your Chevy, enjoying the ride, when suddenly the check engine light illuminates. You pull out your OBD-II scanner, and there it is: chevrolet dtc p0573. Don’t panic! This code, while important, is a common issue many Chevrolet owners face, and it’s often something you can tackle yourself with the right guidance and a few basic tools.

This comprehensive guide from EngineNeeds will walk you through everything you need to know about this specific diagnostic trouble code. We’ll demystify what it means, explore its potential causes, outline the symptoms you might experience, and provide a clear, step-by-step troubleshooting and repair process. Our goal is to empower you to confidently diagnose and fix this problem, ensuring your vehicle’s safety systems are functioning correctly.

Understanding Chevrolet DTC P0573: The Brake Switch Circuit Explained

The chevrolet dtc p0573 indicates a problem within the brake switch “A” circuit, specifically a “High” signal. In plain terms, your vehicle’s Powertrain Control Module (PCM) or Engine Control Module (ECM) is receiving an unexpected high voltage reading from the brake pedal position sensor, also known as the stop lamp switch.

This switch is vital for several functions beyond just illuminating your brake lights. It communicates to various vehicle systems whether the brake pedal is pressed or released. When this signal is incorrect, it can lead to a cascade of other issues.

What Does the Brake Switch Do?

The brake switch is a small but critical component mounted near your brake pedal. Its primary jobs include:

  • Activating your rear brake lights when you press the pedal.
  • Disengaging your cruise control system.
  • Allowing you to shift out of “Park” (shift interlock).
  • Providing input to your anti-lock braking system (ABS) and traction control.
  • In some vehicles, it can even affect engine management or transmission shift points.

When the PCM detects a constant high voltage signal, it means the switch might be stuck “on” or there’s an electrical issue making it appear to be stuck on, even when you’re not pressing the pedal. This is why the P0573 code is triggered.

Common Symptoms of a P0573 Code in Your Chevrolet

While the check engine light is the most obvious indicator, a faulty brake switch or circuit associated with chevrolet dtc p0573 can manifest in several noticeable ways. Paying attention to these symptoms can help confirm your diagnosis.

Visible and Functional Issues

  • Brake Lights Stuck On: This is a very common symptom. Your brake lights may remain illuminated even when your foot is off the pedal. This is a significant safety hazard, confusing other drivers.
  • Cruise Control Malfunction: If your cruise control won’t engage, or disengages unexpectedly, the faulty brake switch is a prime suspect. The system relies on the brake switch signal to know when to turn off.
  • Difficulty Shifting Out of Park: Many automatic transmission vehicles have a shift interlock that requires the brake pedal to be pressed before shifting from Park. A P0573 can prevent this.
  • ABS or Traction Control Light: While less common directly from P0573, an incorrect brake signal can sometimes confuse these advanced safety systems, leading to their warning lights illuminating.
  • No Brake Lights: Conversely, in some rare cases, the high voltage signal might prevent the brake lights from working at all, although “stuck on” is more typical for P0573.

Always address brake light issues promptly. Proper brake light function is crucial for preventing rear-end collisions, especially in heavy traffic or adverse weather conditions.

Diagnosing Chevrolet DTC P0573: Step-by-Step Troubleshooting

Before you start replacing parts, a thorough diagnostic process is essential. This will help you pinpoint the exact cause of your chevrolet dtc p0573 and avoid unnecessary repairs. You’ll need a few basic tools: an OBD-II scanner, a digital multimeter, and possibly some wire strippers/crimpers.

1. Confirm the Code and Clear It

First, use your OBD-II scanner to confirm that P0573 is the only code present. Sometimes, other codes might be related. Clear the code and take your Chevrolet for a short test drive to see if it returns immediately.

  • If the code reappears quickly, the problem is likely persistent.
  • If it doesn’t, it might have been an intermittent glitch.

2. Inspect the Brake Pedal and Switch Assembly

Visually inspect the brake pedal area. Look for anything that might be physically interfering with the brake switch operation.

  • Check the brake pedal return spring. Is it intact and pulling the pedal all the way up?
  • Look for any obstructions, like floor mats, that might be holding the pedal down slightly.
  • Ensure the brake pedal position sensor itself is securely mounted and not loose or damaged.

3. Test the Brake Switch

This is where your digital multimeter comes in handy for a circuit continuity test. The brake switch typically has multiple wires – some for the brake lights, others for cruise control or PCM input.

  • Locate the brake switch, usually above the brake pedal arm.
  • Disconnect the electrical connector.
  • Consult your vehicle’s service manual or a Chevrolet Silverado wiring diagram (if applicable to your model) to identify the correct pins for the brake light circuit.
  • With the ignition off, use the multimeter to check for continuity across the switch terminals. When the pedal is pressed, you should see continuity (or a change in resistance/voltage depending on switch type). When released, there should be no continuity (or a different reading).
  • A common issue for P0573 is a switch that shows continuity even when the pedal is released, indicating it’s stuck “on.”
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4. Check the Wiring Harness and Connectors

The brake switch wiring harness inspection is crucial. A damaged wire or corroded connector can cause a high resistance or short, leading to the P0573 code.

  • Carefully inspect the entire length of the wiring leading to and from the brake switch. Look for chafed, cut, or pinched wires.
  • Check the connectors for corrosion, bent pins, or loose connections. Clean any corrosion with electrical contact cleaner.
  • Ensure the connector is fully seated on the brake switch.

5. Monitor Data Stream with an OBD-II Scanner

Many advanced OBD-II scanners allow you to view live data. This is invaluable for diagnosing a chevrolet dtc p0573.

  • Connect your scanner and look for “brake switch status,” “brake pedal position,” or “stop lamp switch” parameters.
  • Observe the readings as you press and release the brake pedal. It should clearly toggle between “on/off” or varying voltage levels.
  • If the scanner consistently shows “on” or a high voltage when the pedal is released, you’ve likely found your culprit.

If you’re unsure about interpreting live data or performing electrical tests, it’s always best to consult a certified mechanic. Safety is paramount when dealing with vehicle electrical systems.

Common Causes for Chevrolet DTC P0573

Understanding the common culprits behind the brake pedal position sensor high voltage fault can help narrow down your diagnostic efforts. Most often, the problem lies directly with the switch itself or its immediate electrical connections.

Primary Reasons for P0573

  1. Faulty Brake Light Switch / Brake Pedal Position Sensor: This is by far the most common cause. The internal contacts of the switch can wear out, stick, or fail, causing it to send a constant high voltage signal to the PCM, even when the pedal is not pressed.
  2. Misadjusted Brake Switch: The switch needs to be precisely positioned to register pedal movement correctly. If it’s loose or has been knocked out of adjustment, it might not fully disengage when the pedal is released.
  3. Wiring Harness Issues:
    • Chafed or Damaged Wiring: A wire in the brake switch circuit could be shorting to power, causing the high voltage reading.
    • Corroded or Loose Connectors: Poor electrical contact at the switch connector can lead to intermittent or incorrect signals.
  4. PCM (Powertrain Control Module) Failure: While rare, a faulty PCM could misinterpret the brake switch signal or have an internal issue. However, always rule out the switch and wiring first, as PCM replacement is expensive and complex.
  5. Aftermarket Accessories: Improperly installed aftermarket brake lights or trailer wiring can sometimes backfeed power into the brake switch circuit, causing a high voltage condition.

Always start with the simplest and most common causes before moving to more complex and expensive possibilities. The brake switch itself is typically an affordable and relatively easy component to replace.

Repairing Chevrolet DTC P0573: Replacing the Brake Light Switch

If your diagnostics point to a faulty brake switch, replacing it is often a straightforward DIY task. This procedure typically applies to many Chevrolet models, from a Chevrolet Trailblazer EXT to a Silverado.

Tools and Materials You’ll Need:

  • New brake light switch (OEM or reputable aftermarket)
  • Basic wrench or socket set (often 10mm or 13mm)
  • Flathead screwdriver (for prying clips, if applicable)
  • Work light
  • Safety glasses
  • Floor mat or creeper for comfort

Brake Light Switch Replacement Procedure:

  1. Safety First: Park your vehicle on a level surface, engage the parking brake, and turn off the ignition. For extra safety, disconnect the negative terminal of your battery.
  2. Locate the Switch: Get into the footwell area under the dashboard. Look up above the brake pedal arm. The brake switch is usually secured to a bracket near the top of the pedal.
  3. Disconnect Electrical Connector: Carefully press the tab or pull the locking mechanism on the electrical connector and gently pull it off the switch. Avoid yanking on the wires.
  4. Remove the Old Switch: Depending on your Chevrolet model, the switch might twist out, unclip, or be held by a retaining nut.
    • For twist-lock switches: Rotate the switch counter-clockwise a quarter turn and pull it out.
    • For clip-on switches: Use a flathead screwdriver to carefully pry open the retaining clip.
    • For nut-secured switches: Use a wrench or socket to loosen and remove the nut, then pull the switch out.
  5. Install the New Switch: Reverse the removal process. Ensure the new brake light switch replacement procedure aligns correctly with the brake pedal arm. Many switches are self-adjusting, but some may require manual adjustment of the plunger depth. Consult your new part’s instructions or your vehicle’s service manual.
  6. Reconnect Electrical Connector: Push the electrical connector firmly onto the new switch until it clicks into place.
  7. Reconnect Battery and Test: Reconnect the negative battery terminal. Start your vehicle and test the brake lights. Press and release the pedal multiple times. Check that the cruise control engages and disengages properly, and that you can shift out of Park.
  8. Clear DTCs: Use your OBD-II scanner to clear the chevrolet dtc p0573 code from the PCM. Drive the vehicle to ensure the code does not return.

If the code returns, or symptoms persist, revisit your wiring inspection and consider professional help. While rare, a deeper electrical issue or even a PCM problem could be at play.

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Preventive Maintenance and Expert Tips for Your Brake System

Proactive maintenance can help prevent future issues like the chevrolet dtc p0573. A well-maintained brake system ensures not only optimal performance but also your safety on the road.

Tips for Longevity and Performance

  • Regular Visual Inspections: Periodically check your brake lights to ensure they’re functioning correctly. Ask a friend to confirm when you press the pedal.
  • Check Pedal Travel: Be aware of any changes in your brake pedal’s feel or travel. A spongy pedal, or one that sits too high or too low, could indicate issues beyond the switch.
  • Inspect Wiring: During other under-dash maintenance or when changing cabin air filters, take a moment to visually inspect the brake switch wiring harness for any signs of wear or damage.
  • Use Quality Parts: When replacing a brake switch, opt for an OEM (Original Equipment Manufacturer) part or a high-quality aftermarket equivalent. Cheap switches can fail prematurely.
  • Address Other DTCs Promptly: Don’t ignore other diagnostic trouble codes. A problem in one system can sometimes indirectly affect others. For example, issues with your Chevrolet Equinox oil type might not seem related, but keeping your engine healthy is always a good practice.

For off-road enthusiasts, consider the extra stress your vehicle components endure. Mud, water, and vibrations can accelerate wear on electrical connectors and switches. After a particularly rough outing, a quick check of critical connections like the brake switch can save you trouble down the line.

Troubleshooting Matrix: Chevrolet DTC P0573

Use this matrix to quickly identify potential causes and actions based on observed symptoms for your chevrolet dtc p0573.

Common Symptoms, Potential Causes, and Initial Actions

Observed Symptom Most Likely Cause(s) Initial Action(s)
Check Engine Light (P0573) ONLY, Brake Lights Work Normally Intermittent switch fault, PCM glitch Clear code, test drive. If it returns, check switch adjustment and connections carefully.
Brake Lights Stuck ON (with P0573) Faulty brake switch (stuck closed), misadjusted switch Inspect pedal for obstructions. Test brake switch continuity. Replace switch if faulty.
Cruise Control Won’t Engage/Disengages (with P0573) Faulty brake switch (sending “brake applied” signal), wiring issue Test brake switch operation. Check wiring for shorts or open circuits.
Difficulty Shifting from Park (with P0573) Faulty brake switch (not sending “brake applied” signal to shift interlock) Verify brake lights illuminate. Test brake switch function. Check shift interlock wiring.
Intermittent P0573, sometimes with other electrical glitches Loose wiring, corroded connector, intermittent switch failure Thoroughly inspect wiring harness and connectors for damage or corrosion. Perform wiggle test on wiring.
P0573 with other unrelated codes (e.g., engine misfire) Less likely related to brake switch, but potential PCM issue or multiple independent faults Address other codes first, then re-evaluate P0573. Consider professional diagnosis if complex.

This matrix provides a quick reference, but always perform comprehensive diagnostics before replacing parts. A multimeter and an OBD-II scanner are your best friends here.

Frequently Asked Questions About Chevrolet DTC P0573

What is the “A” circuit in Chevrolet DTC P0573?

The “A” circuit typically refers to the primary circuit of the brake switch that sends a signal to the Powertrain Control Module (PCM) and often controls the brake lights. A P0573 code indicates a high voltage condition in this specific circuit, meaning the PCM is seeing a signal as if the brake pedal is pressed, even when it might not be.

Can I drive my Chevrolet with a P0573 code?

While your car might still drive, it’s not recommended to drive for long with a P0573 code, especially if your brake lights are stuck on or not working, or if your cruise control is malfunctioning. This poses a significant safety risk to you and other drivers. Address the issue as soon as possible.

How much does it cost to fix a Chevrolet P0573 code?

The cost to fix a chevrolet dtc p0573 can vary. If it’s just a faulty brake switch, the part itself is usually inexpensive, ranging from $15-$50. Labor at a shop might add another $50-$150. If the issue is more complex, such as a wiring harness repair or, rarely, a PCM replacement, costs could be significantly higher. DIY repair can save you the labor costs.

Does a P0573 code affect my vehicle’s emissions?

Generally, a P0573 code specifically related to the brake switch circuit does not directly affect emissions. However, if the check engine light is on due to this code, your vehicle may fail an emissions test because the “Malfunction Indicator Lamp” (MIL) is illuminated. Fixing the code will allow you to clear the light and pass the test.

Is the brake switch the same as the brake pedal position sensor?

Yes, often these terms are used interchangeably. The brake switch is technically the component, and it acts as a sensor to detect the position (pressed or released) of the brake pedal, sending that signal to the vehicle’s computer systems. For the purpose of diagnosing chevrolet dtc p0573, they refer to the same part.

Conclusion: Drive Safely with a Properly Functioning Brake System

Addressing a chevrolet dtc p0573 promptly is not just about turning off a pesky check engine light; it’s about ensuring the safety and proper function of critical systems in your Chevrolet. Whether you’re a seasoned DIY mechanic or just starting, understanding this code and following a methodical diagnostic approach can save you time, money, and potential hazards on the road.

Remember, always prioritize safety. If you’re uncomfortable at any point during the diagnosis or repair, don’t hesitate to seek assistance from a trusted professional. A correctly functioning brake system is non-negotiable for every driver. Take pride in mastering this common issue, and keep your Chevrolet running safely and efficiently. Happy wrenching!

Robert Lozano
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