P0504 code

Code P0504: Fix “Brake Switch A/B Correlation” Issue

P0504 codeIf you own a car then you know about the error code of OBD. This device is mainly attached to every car for self-diagnosing the car system purposes. And this error code P0504 is one kind of that. This code is related to an issue with the brake system of the car. When you press the brake of the car, it alerts the powertrain control module or PCM alert. so when PCM finds any depressing situation in the brake system it gives an alert in the PCM.

Vehicle brake switch mechanism:

The brake switches are also known as brake sensors, brake switches, and brake light switches. And all these things are the same and it works when the user presses the brake while driving the car. That means when a car driver presses the pedal of the brake, the switch is closed and then the electronic control unit signs the brake is applied there. This switch is also applied in multi-purpose work like the input switch of cruise control, anti-lock brakes, and the brake shift interlock. 

So when the brake system is not connected with the system, it uses separate filaments to stop or turn on the engine check or brake light. But if there is one filament in there for both lights, then the current of the brake takes another way to turn on the switch.

What is the meaning of this error code P0504?

When the car PCM finds any issue with the car brake system it detects it and sends error code P0504. And that’s when the engine check light starts to illuminate. By any chance, if any accident occurs in the system of the brake light, it creates many other issues. And OBD finds the issue from the system and records those issues. The brake is a very important part of every car. If any issue happens there, it also increases the risk of accidents. And that’s why when any vehicle finds this error code in the car, the MIL light starts blinking. Another reason for this error code is if the user’s car damaged the brake light. And it remains on until the user receives this code from the PCM. and repairing this code as soon as possible is recommended. 

What is the reason for this error code P0504?

One issue is not the villain of this code, there are a bunch of problems that are behind this error code P0504. If you want to solve this issue by yourself or get confused then you must need to know what are the main reasons behind this trouble code. Here we listed some main causes of this P0504 code below:error code P0504

  • Defect in brake light switch,
  • Adjustment issue of the brake pedal,
  • Loose or damaged wiring,
  • PCM failure,
  • Defective ECM,
  • Malfunction in brake light fuse,
  • Faulty brake light bulb,
  • Open or short harness of brake switch.

What are the common symptoms?

Just like cause, there are many symptoms you can find in your car that are related to error code P0504. And if you are an expert you can easily find the solution from it. That’s why knowing the symptoms of this error code is important. The basic symptoms you face with this issue are given below:

  • Turn on the engine check light,
  • The issue in shifting,
  • Engine stalling in braking time,
  • Cruise control issue,
  • Sometimes brake light won’t turn on at all,
  • Disengage the brake pedal.

How to diagnose the error code P0504?

From mechanic to car repair DIY user, both use a digital scanner to find the issue in the car at first. Then they switch on the ignition and read all previous and present code from the scanner. After that visual inspection is the second stage to find the issue from the car hardware. They look at all possible areas of the brake light and its whole system. 

If they don’t find any issue in there, they move to the switch of the brake system. Because sometimes loose or damaged wiring is the villain behind this P0504 code. For that, they also use the car manual and match everything according to their design. 

But if they also failed to find any issue there, eliminating all wiring harnesses and connectors is the next stage. And then they run the scanner again, whether the code is still there or not. If the code still shows up on the screen, the DIY users are recommended to contact any professional to get rid of this error code from the device and professional ones are again to judge all this thing. 

Alert! Common Mistakes

There are some common mistakes many DIY and professionals made to find this issue from the car. The top mistake is if the driver depresses the brake pedal, it won’t turn on the brake light. From that, they just assume that the issue is the brake light, either it burnt or got loose from its place. So without thinking further they just change the light and instead go to the deeper examination.  

How to solve the error code P0504?

If you fulfill every step in the upper portion and find the main culprit of this error code P0504, then it’s time to repair the car with some simple method. and those easy steps are given below:

  • If the brake light gets burned, then replace the old one with a new light
  •  Look at the fuses system of the brake. If there is any damage in there, restore the fuse with a new one.
  • If there is any wiring issue in there, point out the area. Then try to repair this as soon as possible. But if the problem is not repairable, then replace the whole wiring on the brake system and do it again with new wiring and connectors.
  • If the issue is related to a broken brake switch, replace it.

After doing every step properly, clear the code from the memory of the car scanner and test the car with a small drive. Then again run the scanner to find any issue still remaining in there. If the code again pops up on the screen, then the problem is still not solved. You can get help from technical bulletins, it has every detail of every car with a solution. But my suggestion is to contact a professional car mechanic. They can easily find the issue and the reason with their updated digital premium scanner. It’ll cost you some money but save some time and also assure you the problem is gone from the system.

How serious is the error code P0504?

If you read the whole article you must know this code related to the issue with the brake system, when cars are unable to turn on the brake light after releasing the brake pedal. And this is a critical issue for every car owner. Because without this brake, you can’t take control of your car, like you can’t slow down your car at the same speed. And it’s worse in the nighttime. So if you ignore the code, it may lead you to a big accident that is not expected by anyone. And that’s why you need to contact your mechanic right that time and fix the issue instantly.

How much does it cost to solve the trouble code P0504?

There are a few changes we are discussing in there. So now it’s time to talk about the cost of repairing the  P0504 code from the car. The car repair labor and replacement cost mainly are not fixed, it differs with the location and also the part that needs to be replaced. That’s why it is really mandatory to find the main culprit of this issue and then change it. like the price of brake light switch around $50-$160, but this price also differs for car model and version. But don’t think about the price, fix the issue as fast as you can.

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