P0573 on 2012-2018 Chrysler 300: Brake Switch Faults and Fixes

What's Unique About the 2012-2018 Chrysler 300

On many cars, P0573 is a straightforward brake switch failure. However, on the 2012-2018 Chrysler 300 and its platform mates (Dodge Charger, Dodge Challenger), Chrysler has issued multiple Technical Service Bulletins (TSBs) indicating that this code can be erroneously triggered by a software glitch in the Powertrain Control Module (PCM). Before replacing any parts, it's critical to determine if the vehicle's PCM software is up-to-date, as a simple reflash could be the correct and only necessary fix. [Bulletin #18-020-13, 16]

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Cruise control is inoperative or will not engage.
• Adaptive Cruise Control (if equipped) is inoperative. [Bulletin #1811822, 3]
• Brake lights may not work when the pedal is pressed.
• Brake lights may stay on continuously.
• ABS or traction control warning lights may illuminate.
• Difficulty shifting out of Park.

Most Likely Causes

1. Outdated Powertrain Control Module (PCM) Software 🔴 High Probability Chrysler released a specific TSB (#18-020-13) to address an 'Erroneous P0573' code, indicating a known software issue that falsely triggers this fault on 2012-2013 models. This is the most critical first check.
   How to confirm: A Chrysler dealership or a qualified repair shop with access to OEM software (like wiTECH) can check the current PCM calibration against available updates.
   Typical fix: Selectively erasing and reprogramming the PCM with the latest software version. This is often referred to as a 'flash'. The process requires a stable power supply to the vehicle and the wiTECH software level must be at release 13.03 or higher.
   Est. part cost: $0
2. Faulty Brake Light Switch 🔴 High Probability The brake light switch is a high-use component that can fail electrically or mechanically over time. It can also be damaged by being kicked or dislodged from its mounting bracket on the brake pedal assembly.
   How to confirm: Use a scan tool to monitor the brake switch status in live data while pressing and releasing the pedal. If the status doesn't change, or if a multimeter test shows the switch is not opening/closing its internal circuits correctly, it has failed. A proper switch should pull the circuit to ground (0V) when the pedal is depressed.
   Typical fix: Replace the brake light switch located on the brake pedal support bracket. The new switch must be properly adjusted upon installation; it is rotated about 30 degrees to lock into place and is not reusable once removed.
   Est. part cost: $25-$50
3. Wiring or Connector Issue 🟡 Medium Probability The wiring near the brake pedal can be kicked or stressed, leading to damage. Corrosion can also affect the connector pins, causing a high resistance or short-to-voltage condition.
   How to confirm: Visually inspect the wiring harness and connector at the brake light switch for any signs of damage, chafing, or corrosion. Perform a voltage and ground check at the connector with a multimeter, referencing the vehicle's wiring diagram.
   Typical fix: Repair the damaged section of wiring or clean/replace the connector.
   Est. part cost: $5-$20

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): While a software glitch is common, a hardware failure within the PCM itself is rare but possible if all other causes have been ruled out. This would be an expensive repair, often exceeding $900.
• Blown Fuse: A blown fuse related to the brake light or cruise control circuits can sometimes trigger this code. Check the fuse box as an early diagnostic step.

Diagnosis Steps

1. Scan for Codes: Use an OBD-II scanner to confirm P0573 and check for any other codes, especially U0140.
2. Check for TSBs: Specifically check if TSB #18-020-13 (or its revisions) applies to your vehicle's VIN and build date. This should be the first step to avoid unnecessary parts replacement.
3. Verify PCM Software: Have a dealer or qualified shop check if your PCM software is current. If an update related to P0573 is available, this is the most likely fix. A dealer flash typically costs $150-$300.
4. Inspect Brake Light Operation: Check if the brake lights function correctly. If they are stuck on or do not illuminate, it points more strongly toward the switch or wiring.
5. Test the Brake Switch: Use a scan tool's live data to observe the 'Brake Switch' status as you press and release the pedal. The status should change instantly. Alternatively, remove the switch and test its circuits with a multimeter for continuity.
6. Inspect Wiring: Visually inspect the brake switch connector and nearby wiring for any damage, looseness, or corrosion. Ensure the switch is securely mounted in its bracket.
7. Test the Circuit: If the switch seems to work but the code persists, use a multimeter to test for correct voltage and ground at the switch connector according to the vehicle's wiring diagram. Check for resistance below 10.0 Ohms on the signal circuit to the PCM.
8. Replace the Brake Switch: If the switch is confirmed to be faulty, replace it. Ensure the new switch is installed and adjusted correctly.
9. Final PCM Check: If all other steps fail, the issue may be a rare hardware fault in the PCM, which requires professional diagnosis.

Parts You'll Likely Need

• Brake Light Switch (OEM #4671336AD) — This switch is the most common hardware failure for this code. It is a high-wear item that signals brake pedal position to the PCM. The part number 4671336AD supersedes previous versions 4671336, 4671336AB, and 4671336AC.
  Trusted brands: Mopar, Duralast, SMP (Standard Motor Products)
  OEM price range: $40-$60
  Aftermarket price range: $25-$45

Related Codes That Often Appear With This One

• U0140 — Multiple TSBs for the Chrysler 300 list P0573 and U0140 (Lost Communication With Body Control Module) appearing together, suggesting a related electrical or module communication issue that is often resolved by the same PCM software update. [Bulletin #18-070-16, #18-102-15, #18-011-15 REV. A]
• P0300 — Some TSBs also note that P0573 can appear alongside P0300 (Multiple Cylinder Misfire), though the direct link is likely a complex software interaction within the PCM that a reflash is designed to correct. [Bulletin #18-070-16, #18-011-15 REV. A]

Technical Service Bulletins (TSBs) & Recalls

• 18-020-13: Flash: Erroneous P0573- Brake Switch 1 Stuck Off
• 1811822: Adaptive Cruise Control inoperative... DTC... P0573 - Brake Switch 1 Stuck Off
• 18-070-16: Lists P0573 - Brake Switch 1 Stuck Off along with U0140 and P0300.
• 18-102-15: Lists P0573 - Brake Switch 1 Stuck Off along with U0140.
• 18-011-15 REV. A: Lists P0573 - Brake Switch 1 Stuck Off along with U0140 and P0300.

Platform-Specific Known Issues

• A known software glitch can cause an 'Erroneous P0573' code, which is fixed by reprogramming the PCM, as documented in TSB #18-020-13. This is the most important vehicle-specific consideration.
• This code is frequently associated with the Adaptive Cruise Control becoming inoperative, as noted in TSB #1811822.
• It often appears with communication code U0140, pointing to a broader network or module issue rather than just a simple switch failure. A PCM flash often resolves both codes simultaneously. [Bulletin #18-070-16, #18-102-15]
• Owners on forums like 300cforums.com frequently report that a trip to the dealer for a software update resolved the code after they had already replaced the brake switch with no success.

Mechanic-Grade Diagnostic Values

• Brake Switch Signal Circuit Resistance — expected: Below 10.0 Ohms. Failure: Resistance above 10.0 Ohms indicates an open or high-resistance in the circuit.
• Brake Switch Signal Circuit Voltage (Testing for short to voltage) — expected: Below 1.0 Volt. Failure: Voltage above 1.0 Volt indicates a short to a power source.
• Brake Switch Signal Voltage (Pedal Depressed) — expected: Approximately 0 Volts. Failure: Voltage significantly above 0V when the pedal is pressed indicates a faulty switch or bad ground.

Scan Tool Commands That Help

• wiTECH: Powertrain Control Module (PCM) Reprogramming/Flash — This is the primary repair for the 'Erroneous P0573' code specified in TSB #18-020-13, especially on 2012-2013 models.
• wiTECH or equivalent professional scanner: Module Self-Test / Communication Verification — To check the health of the Body Control Module (BCM) if wiring and the switch test good, as a faulty BCM can be a rare cause.
• wiTECH or AlfaOBD: Brake Pedal Position Sensor Calibration — After replacing the brake light switch, a calibration may be needed to ensure the new sensor's output is correctly interpreted by the vehicle's modules.

Wiring & Ground Locations

• Brake Light Switch — Mounted to the brake pedal support bracket, located above the brake pedal arm under the driver's side dashboard.. This is the primary sensor for this code. Its physical location makes it susceptible to being kicked or dislodged.
• Body Control Module (BCM) — Located behind the passenger's side kick panel for the 2012 model year.. The brake switch signal is processed through the BCM. A fault in the BCM or its connector can trigger P0573, often along with code U0140.
• G911 — A ground point located on the left side of the dash.. A poor ground connection at this location can cause various electrical issues, including incorrect voltage readings from sensor circuits like the brake switch.
• G305 — A ground point located at the base of the right 'C' pillar on RWD 300 models.. This is a major body ground. While less direct, ensuring all major grounds are clean and secure is a key step in resolving persistent electrical faults.

Real Owner Repair Stories

• YouTube channel 'JJ Central' (Dodge vehicle (platform mate, model years 1998-2017 cited as similar)) — Check Engine Light, stability control light on, cruise control not working.
  ❌ Tried (didn't work) The owner went straight to replacement after scanning the codes.
  ✅ What actually fixed it Replacing the brake pedal position switch fixed all symptoms. The owner noted the car seemed to self-recalibrate for a few seconds after the new switch was installed.

"I Checked Everything" — The Actual Cause

• This is an electrical code not typically diagnosed with a smoke test. The equivalent scenario is when the brake switch and wiring test perfectly fine with a multimeter, yet the code persists. On the 2012-2018 Chrysler 300, this situation almost always points back to the need for a Powertrain Control Module (PCM) software update as detailed in Chrysler's Technical Service Bulletins.

OEM Part Supersession History

• 4671336, 4671336AB, 4671336AC → 4671336AD — Standard part revision and improvement by the manufacturer.
  Heads up: No known incompatibilities; the latest version (4671336AD) is the correct service replacement.

Model Year Variations Within This Range

• 2012: TSB #18-020-13 specifically addresses an 'Erroneous P0573' code on 2012 models with the 6.4L engine built before April 29, 2012, requiring a PCM reflash. This makes a software check the absolute first step for this specific subset of vehicles.