P0504 - OBD Trouble Code

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When a defect takes place in the circuit of the brake light, multiple issues can happen. To stay safe and out of danger, this code will come into play, and the Check Engine Light will stay on until resolving the reason for the problem, and the code is erased out of the PCM.

The Brake Switch explains to the engine control module (PCM) that the brake pedal is impaired. This particular switch also has a job of managing the brake lights. If the PCM checks for an improper signal from the Brake Switch, the PCM will set code P0504.

What causes this problem with the Brake Switch "A"/"B" Correlation?

Multiple problems can cause the recording of P0504 code, but luckily a majority of them are equally simple and easy to diagnose. These include:

• A blown up or malfunctioned brake light fuse
• A damaged or faltered brake light switch
• A blown-up brake light bulb
• A shorted or open brake switch harness
• An issue with the electrical connection or circuit for the brake switch

1. Brake Connectors - The same as using a brake pedal, but in this case, you are using the parking brake cable instead of brake fluids to apply for pressure. The cable can rust and break over the time of usage. If having a broken parking brake cable, this will roll the car, even when you have engaged the parking brake. Make sure to always apply the parking brake when the car is being parked. This will keep the parking brake correctly adjusted. Your mechanic should examine the parking brake cable throughout each brake service.
2. Brake Light Fuse - An important symptom that is commonly related with a negative brake light switch are brake lights that remain on all the time. If the brake light switch shorts centrally it might make the brake lights to keep illuminating, even if the pedal is not being pushed. This makes the brake lights burn out even sooner than they’re supposed to be, and cause for an infested drainage on the battery. If you surmise that your vehicle’s brake light switch could be negative or failing, have the brake lights monitored by a professional mechanic.
3. Brake Fuse - The brake fuse is capable of blowing up when the brake light bulbs on the circuit are destroyed and its contacts meltdown to an extent that they touch and produce a short. Another associated bulb defect occurs if the threads in a double threaded bulb go shorted together. If the issue is not discovered in the bulbs or contacts, generally any wire, ground, or component in the fused circuit is a probably reason for the cause. Check the bulbs and terminals methodically to find out about any cause for these failures. If there is no success, find a professional mechanic that can fix this for you at an auto shop, over a touch screen mobile, and at reasonable expenses. 

We at Parts Avatar Canada care about our customers, and that’s why we will help you to diagnose P0504 code by listing out some major symptoms. They are described below as follows

Common Symptoms

The cruise control system might go defective to connect or disconnect when the brake pedal is impaired, the brake lamps, which are on the backing of the vehicle, might even stay illuminated or fail at being illuminated, in which the shift interlock system may fail in operating correctly, or the engine may begin stalling when the brakes are impaired at certain highway speeds.

• Pushing the brake pedal does not connect or disconnect the vehicle’s cruise control system.
• One or both brake lights will not turn on when pushing the brake pedal.
• One or both brake lights stay on, even after lifting your foot off of the brake pedal.
• Pushing the brake pedal at highway speeds causes the engine to stall.
• The shift interlock system fails to work correctly.

Learn the ways with which you can correct this trouble code:

In a majority of cases, repairing the cause of a P0504 code is very simple and straightforward. It all depends on what the root issue is, and some of the most frequent repairs include:

• Replacing a scorched-out brake light bulb.
• Repairing or replacing wires or connectors for the brake switch harness or circuit.
• Replacing the brake switch.
• Replacing a blown-up brake light fuse.

Don’t tense up if you are still dealing with all these issues as we care about our customers and that’s why we provide a essential range of Connectors, Brake Light Fuse, Brake Fuse and a lot more. We are confident that all your problems will be resolved.

It is high priority to diagnose this defected code. Here are a few steps to how a mechanic should follow up for diagnosing the issue that sources a P0504 code to be stored:

After identifying the P0504 code with an OBD-II scanner, the mechanic will clear the code and then perform an inspection of all possible causes for the code. They will start by testing the brake light fuse, and then they will test and/or replace the brake light bulb. If these measures do not fix the problem, they will move on to test the brake switch itself, as well as its wiring and connectors.

Common Mistakes When Diagnosing the P0504 Code

Often, when a brake light does not turn on when the driver impairs the brake pedal, they will assume the issue is a bulb that has been burnt out. They may have to replace the bulb and find out if this does nothing to solve the issue. If there is an undisclosed issue with the brake switch or circuit, replacing a blown-up brake fuse may also be a mistake, as the sourced problem will likely cause the fuse to blow up again.