Experiencing issues with your Jeep’s traction control system and encountering the P0571 error code? You’re not alone. Many Jeep owners have faced similar frustrations. This guide will walk you through identifying a common culprit behind the P0571 code – a faulty brake switch – and how you can easily fix it yourself. If you’re seeing the P0571 code along with traction control system warnings, this straightforward repair might just be the solution you need.
It started subtly. Towards the end of 2020, my Jeep Wrangler occasionally flashed the traction control system (TCS) failure light. This warning light, sometimes humorously called “Car Snakes” due to its serpentine car-chasing icon, would appear sporadically.
The “Car Snakes” light is a key indicator of a potential issue with your Jeep’s Traction Control System. It’s important to differentiate this from the “TCS OFF” light, which simply means the system is intentionally disabled. The “Car Snakes” light, however, signals that the computer has detected a problem and has disabled TCS for safety.
Jeep’s TCS, like most modern vehicles, relies on selectively applying brakes to individual wheels to regain control when slippage is detected. This intricate system requires two crucial components to function correctly:
- Wheel Speed Sensors: These sensors, located at each wheel, constantly monitor wheel rotation speed. This data is vital for the computer to detect discrepancies that indicate wheel slip.
- Electronic Braking (ABS): The Anti-lock Braking System (ABS) allows the computer to apply brakes automatically to individual wheels as needed for traction control.
Therefore, any disruption or confusion within these systems can lead to the computer disabling TCS as a precautionary measure. Initially, the intermittent TCS light suggested a possible issue with the wheel speed sensors. However, the situation escalated when my Jeep illuminated the check engine light and displayed the P0571 diagnostic trouble code (DTC).
The P0571 code, clearly displayed on my OBD-II reader, pointed to a “Cruise Control/Brake Switch A Circuit Malfunction”. This code strongly suggested that the root of the problem was related to the braking system, specifically the brake switch circuit. This revelation shifted the focus from wheel speed sensors to the brake system itself.
Armed with this new information, I cleared the code and began carefully observing when the error recurred. It soon became apparent that the P0571 error was often triggered when braking – approaching traffic lights, reversing, or during similar braking maneuvers.
Further research revealed a crucial detail about Jeep’s braking system: it utilizes two independent brake sensors.
- Computer-Monitored Brake Sensor: This sensor sends a signal through the Totally Integrated Power Module (TIPM) to the main computer when the brakes are applied.
- Physical Pedal Position Switch: A separate switch located directly behind the brake pedal detects the pedal’s physical position.
Interestingly, I discovered that in JK Wranglers and similar models, the third brake light is connected to the physical pedal switch, while the main brake lights are routed through the TIPM. This wiring configuration provided a valuable diagnostic opportunity.
I decided to test if I could activate one set of brake lights independently of the other. By applying very gentle pressure to the brake pedal, I was able to illuminate the third brake light without activating the main brake lights.
This wasn’t consistent with every brake application, but with a light, “coasting” brake pedal press, it became reliably repeatable. This observation led me to suspect that the physical pedal brake switch was failing. It appeared worn or misaligned, causing inconsistent signal transmission depending on the pedal pressure.
The brake switch itself is a small, unassuming plastic component with a spring-loaded plunger extending from one end.
This plunger is designed to make contact with the brake pedal arm. However, if the switch is worn or misaligned, this contact can become unreliable. While some online resources suggested realignment as a potential fix, the low cost of a genuine Mopar replacement switch – around $20 – made replacement the more appealing and reliable option. I promptly ordered a new brake switch.
Replacing the brake switch is a surprisingly simple and quick task. The first step is to remove the lower dash panel located beneath the steering wheel.
With the outer panel removed, you’ll gain access to a metal access plate, which should also be removed.
Removing this inner panel reveals the brake switch, easily accessible for most arms to reach through the opening.
To replace the brake switch:
- Unlock: Turn the module counter-clockwise to disengage it from the mounting plate.
- Disconnect: Detach the wire harness from the old switch.
- Connect: Attach the wire harness to the new replacement switch.
- Lock: Press the new switch into the mounting plate and turn it clockwise until it securely locks into position.
While this repair successfully resolved my P0571 and TCS issues, it’s important to remember that automotive problems can have various causes. However, given the ease and low cost of this fifteen-minute brake switch replacement, it’s certainly worth considering if you are experiencing similar symptoms with your Jeep. This simple DIY fix might just save you a trip to the mechanic and get your Jeep back to optimal performance.
