AutoCodes – Toyota – P0504 2005 Toyota Highlander

P0504 2005 Toyota Highlander Code - Brake Switch Circuit 'A' / 'B' Correlation

Quick Answer

In addition to turning on the stop lamp, the stop lamp switch signals are used for a variety of engine, transmission, and suspension functions as well as being an input for diagnostic checks. Common causes include Faulty stop lamp switch, Blown stop lamp bulb, Brake switch harness open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0504 2005 Toyota Highlander indicates Brake Switch Circuit 'A' / 'B' Correlation.
Common causes: Common causes include Faulty stop lamp switch, Blown stop lamp bulb, Brake switch harness open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 6,184

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Basic DIY (1 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0504 2005 Toyota Highlander Description

In addition to turning on the stop lamp, the stop lamp switch signals are used for a variety of engine, transmission, and suspension functions as well as being an input for diagnostic checks. It is important that the switch operates properly, therefore this switch is designed with two complementary signal outputs: STP and ST1.
The Engine Control Module (ECM) analyzes these signal outputs to detect malfunctions in the stop lamp switch.

OBDII Code P0504 2005 Toyota Highlander - Brake Switch Circuit 'A' / 'B' Correlation - AutoCodes.com — P0504 2005 Toyota Highlander Code - Brake Switch Circuit 'A' / 'B' Correlation

What does this mean?

What are the Possible Causes of the DTC P0504 2005 Toyota Highlander?

Faulty stop lamp switch
Blown stop lamp bulb
Brake switch harness open or shorted
Brake switch circuit poor electrical connection
ECM

How to Fix the DTC P0504 2005 Toyota Highlander?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Check the bulb and fuse first, if they are good replace stop lamp switch.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0504 2005 Toyota Highlander code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0504 2005 Toyota Highlander code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0504 2005 Toyota Highlander Code

1. What does the OBDII code P0504 mean for a 2005 Toyota Highlander?

P0504 indicates a fault in the correlation between the Brake Switch Circuit 'A' and 'B', meaning the signals from the two brake switch circuits are not aligning as expected.

2. What are the common symptoms of code P0504 in a 2005 Toyota Highlander?

Symptoms may include the brake lights not functioning properly, the cruise control being disabled, and potentially illuminated ABS or check engine lights.

3. What causes the P0504 code to appear in a 2005 Toyota Highlander?

Common causes include a faulty or misaligned brake light switch, damaged or corroded wiring or connectors, or an issue with the brake pedal assembly.

4. Can I drive my 2005 Toyota Highlander with the P0504 code?

While the vehicle may still be drivable, it's not recommended as faulty brake lights can pose a safety hazard, and cruise control may not function properly.

5. How do I diagnose the P0504 code on my 2005 Toyota Highlander?

Start by inspecting the brake light switch and pedal assembly for physical damage or misalignment, then check the wiring and connectors for corrosion or damage. Use a multimeter to test circuit continuity if needed.

6. How do I fix the P0504 code on a 2005 Toyota Highlander?

The most common fix is replacing the faulty brake light switch. If the wiring or connectors are damaged, they should be repaired or replaced. Calibration of the brake switch may also be necessary.

7. How much does it cost to repair the P0504 code on a 2005 Toyota Highlander?

Repair costs can range from $50 to $150 for a brake light switch replacement, while wiring repairs may cost more depending on the extent of the damage.

8. Will replacing the brake light bulb fix the P0504 code?

No, the P0504 code is related to the brake switch circuit, not the brake light bulb. However, ensuring the brake lights work can help confirm the issue lies in the switch or wiring.

9. Can a P0504 code trigger the ABS light in a 2005 Toyota Highlander?

Yes, the ABS system may illuminate the warning light because it relies on signals from the brake switch to function properly.

10. Do I need special tools to fix the P0504 code in a 2005 Toyota Highlander?

Basic tools like a multimeter and a screwdriver are typically sufficient for diagnosing and replacing the brake light switch. In some cases, a scan tool may be needed to clear the code.