What is P0504 fault code? What is the explanation for Brake Switch “A”/”B” Correlation failure? How do I fix the fault code P0504? What are the causes and symptoms for the P0504 fault code
What is the P0504 Fault code? What does it mean
If the powertrain control module, PCM detects faults in the brake light switch, a code P0504 will be triggered. The word “correlation” In the description of this code, it is indicated that the system does NOT respond when the PCM sends electricity to brake switch circuit.
Brake switch. It’s an essential component that lets drivers behind you know that you are braking or slowing down your vehicle by pressing the brake pedal. The switch creates a circuit by pressing the brake pedal and causes the brake lights turn on.
However, the brake circuit is connected to other circuits/systems such as the shift lock safety and cruise control. The cruise control system can be disengaged by pressing the brake. This will temporarily turn on the brake lights as well as disable the cruise system. On some vehicles, the cruise control system cannot be started or the automatic transmission moved out of the “P”, “N” positions without pressing the brake pedal. This activates the circuit.
When the vehicle is started, the PCM checks all electrical circuits. If the PCM detects an issue with the brake light circuit, the code P0504 will be set.
Vehicles susceptible to the P0504 fault code include but are not limited: Toyota, Ford Honda, Hyundai Jaguar, Mitsubishi Citroen Jeep, Volvo, Alfa Romeo Duramax Fiat, Renault, Kia, Toyota, Ford, Honda and Hyundai.
What causes the P0504 Fault code?
Although there are many problems that can lead to a P0504 code being registered, most of these problems can be easily diagnosed and fixed.
Here are some reasons why P0504 should be set.
- – A faulty or damaged brake switch
- – The brake switch wiring harness wiring harness wiring has been damaged, burnedt, disconnected, or corroded.
- – Broken or defective brake light fuse
- – Broken brake bulbs
- – An issue with the circuit or electrical connection of the brake switch
- – Defective PCM (rarely)
What are the Symptoms of P0504’s Fault Code?
These symptoms may be present in vehicles with code P0504.
- – Illumination at the check engine lights
- – Lighting of any other relevant malfunction lights (e.g., electronic engine light malfunction)
- – When the brake pedal is pressed, cruise control system doesn’t activate or deactivate.
- – The brake lights don’t come on when either one or both are depressed.
- – Even if you don’t press the brake pedal, the brake lights will still turn on.
- – Engine stops when you press the brake pedal while driving
- – Sometimes the fault recurs and the engine doesn’t stop. In these cases the vehicle will continue to idle while the accelerator pedal is unresponsive.
- – Sometimes it may be difficult to move the gear lever from the “P” or the “N” position.
How do I fix the P0504 fault code?
This is the most common mistake when trying to solve this problem. The problem may be caused by a fault in the circuit or brake switch, or the fuse blowing. Replacing the bulbs might not solve the problem. The fault may be caused by blown brake light fuse fuses. Otherwise, the fuses could blow again.
Here are some of the possible repairs that could resolve the P0504 fault code:
- – Replace or repair damaged, corroded or shorted cables and connectors to the brake switch circuit.
- How to replace a broken brake switch
- – Replacing the blown brake light fuse
- – Replacing blown brake lights bulbs
Note: This code can activate the electronic fault lamp, particularly in Renault Clio II vehicles. The light will turn the accelerator pedal off and on. Most times, when you turn off the ignition switch and turn it on, the light will go out. It will then be normal again, but the fault could reappear very soon. When the vehicle is stationary, gently tap the socket and the brake pedal switch. Replace the connector or brake switch if the electronic fault light comes on and the accelerator pedal does not respond.
How serious is the P0504 Fault code?
Driving safety is at risk if the brake pedal lights fail to turn on and off. It is possible for other drivers or drivers to be surprised if you are not cruising at the right speed, especially at night. This could result in potentially dangerous situations. Accidents can also occur if the cruise controller system doesn’t deactivate when the brake pedal is pressed. Additionally, vehicles with malfunctioning brake lamps cannot be passed inspection. Fault code P0504 should therefore be taken seriously and rectified as soon as possible.
